文章
Dummer. ゛☀
2017年09月14日
Sometimes called jumping plant lice, psyllids feed on a variety of plants including most fruit trees and small fruits as well as tomato and potato. Both adults and nymphs feed by piercing the leaf surface and extracting cell sap. This causes foliage (especially the upper leaves) to turn yellow, curl and eventually die. Honeydew secreted by the psyllids encourages the growth of dark sooty molds. Many species transmit disease-carrying viruses.
Adults (1/10 inch long) are reddish brown in color with transparent wings and strong jumping legs. They are very active and will hop or fly away when disturbed. Nymphs are flat and elliptical in shape, almost scale-like. They are less active than adults and are most numerous on the undersides of leaves. Newly hatched nymphs are yellowish in color but turn green as they mature.
Note: Psyllids are monophagous which means that they are host specific (each species feeds on only one plant type).
Life Cycle
Adults overwinter in crevices on tree trunks. In early spring they mate and females begin depositing orange-yellow eggs in the crevices about the buds, and after the foliage is out, on the leaves. Hatching occurs in 4-15 days. Yellow to green nymphs pass through five in instars in 2-3 weeks before reaching the adult stage. There are one to five generations per year depending on species.
Psyllid Control
To get rid of psyllids spray horticultural oil in early spring to destroy overwintering adults and eggs.
Beneficial insects, such as ladybugs and lacewing, are important natural predators of this pest. For best results, make releases when pest levels are low to medium.
If populations are high, use a least-toxic, short-lived natural pesticide to establish control, then release predatory insects to maintain control.
Diatomaceous earth contains no toxic poisons and works quickly on contact. Dust lightly and evenly over vegetable crops wherever adults are found.
Safer® Insecticidal Soap will work fast on heavy infestations. A short-lived natural pesticide, it works by damaging the outer layer of soft-bodied insect pests, causing dehydration and death within hours. Apply 2.5 oz/ gallon of water when insects are present, repeat every 7-10 day as needed.
Surround WP (kaolin clay) forms a protective barrier film, which acts as a broad spectrum crop protectant for preventing damage from insect pests.
70% Neem Oil is approved for organic use and can be sprayed on vegetables, fruit trees and flowers to kill eggs, larvae and adult insects. Mix 1 oz/ gallon of water and spray all leaf surfaces (including the undersides of leaves) until completely wet.
If pest levels become intolerable, spot treat with insecticides approved for organic use every 5-7 days. Thorough coverage of both upper and lower infested leaves is necessary for effective control.
Adults (1/10 inch long) are reddish brown in color with transparent wings and strong jumping legs. They are very active and will hop or fly away when disturbed. Nymphs are flat and elliptical in shape, almost scale-like. They are less active than adults and are most numerous on the undersides of leaves. Newly hatched nymphs are yellowish in color but turn green as they mature.
Note: Psyllids are monophagous which means that they are host specific (each species feeds on only one plant type).
Life Cycle
Adults overwinter in crevices on tree trunks. In early spring they mate and females begin depositing orange-yellow eggs in the crevices about the buds, and after the foliage is out, on the leaves. Hatching occurs in 4-15 days. Yellow to green nymphs pass through five in instars in 2-3 weeks before reaching the adult stage. There are one to five generations per year depending on species.
Psyllid Control
To get rid of psyllids spray horticultural oil in early spring to destroy overwintering adults and eggs.
Beneficial insects, such as ladybugs and lacewing, are important natural predators of this pest. For best results, make releases when pest levels are low to medium.
If populations are high, use a least-toxic, short-lived natural pesticide to establish control, then release predatory insects to maintain control.
Diatomaceous earth contains no toxic poisons and works quickly on contact. Dust lightly and evenly over vegetable crops wherever adults are found.
Safer® Insecticidal Soap will work fast on heavy infestations. A short-lived natural pesticide, it works by damaging the outer layer of soft-bodied insect pests, causing dehydration and death within hours. Apply 2.5 oz/ gallon of water when insects are present, repeat every 7-10 day as needed.
Surround WP (kaolin clay) forms a protective barrier film, which acts as a broad spectrum crop protectant for preventing damage from insect pests.
70% Neem Oil is approved for organic use and can be sprayed on vegetables, fruit trees and flowers to kill eggs, larvae and adult insects. Mix 1 oz/ gallon of water and spray all leaf surfaces (including the undersides of leaves) until completely wet.
If pest levels become intolerable, spot treat with insecticides approved for organic use every 5-7 days. Thorough coverage of both upper and lower infested leaves is necessary for effective control.
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文章
Dummer. ゛☀
2017年09月14日
Many species of leafhoppers exist in home gardens throughout North America. Both adults and nymphs feed by puncturing the undersides of leaves and sucking out plant juices. Their toxic saliva causes spotting (white specks), yellowing, leaf curling, stunting and distortion of plants. They are also responsible for transmitting the organisms causing virus diseases in plants. Common host plants include beans, lettuce, beets, potato, grapes, roses and many others.
Leafhopper adults (1/4 inch long) are slender, wedge-shaped insects that fly or disperse rapidly when disturbed. Depending on species they may be green, brown or yellow in color and often have colorful markings. Nymphs do not have wings and are generally lighter in color than adults. Both adults and nymphs run sideways and are good jumpers.
Note: There are more leafhopper species worldwide than all species of birds, mammals, reptiles and amphibians combined.
Life Cycle
Adults overwinter in crop debris or non-cultivated areas adjacent to gardens. In late spring females deposit 1-6 eggs daily within the stems and larger veins of the leaves. Hatching occurs in 6-9 days, and the young nymphs molt 5 times before they become fully grown adults. White cast skins shed by the molting nymphs can often be found attached to the underside of damaged leaves. The period from egg to adult is about three weeks. Several overlapping generations may be completed during the growing season.
Leafhopper Control
Remove garden trash and other debris shortly after harvest to reduce over-wintering sites.
Floating row covers can be used as a physical barrier to keep leafhoppers from damaging plants.
Commercially available beneficial insects, such as ladybugs, lacewing and minute pirate bugs, are all voracious predators of both the egg and young larval stage.
Apply diatomaceous earth to plants and/or spot treat with insecticidal soap to keep pest populations under control. Thorough coverage of both upper and lower infested leaves is necessary for effective control.
If pest levels become intolerable, spot treat with potent, fast-acting organic insecticides as a last resort.
Leafhopper adults (1/4 inch long) are slender, wedge-shaped insects that fly or disperse rapidly when disturbed. Depending on species they may be green, brown or yellow in color and often have colorful markings. Nymphs do not have wings and are generally lighter in color than adults. Both adults and nymphs run sideways and are good jumpers.
Note: There are more leafhopper species worldwide than all species of birds, mammals, reptiles and amphibians combined.
Life Cycle
Adults overwinter in crop debris or non-cultivated areas adjacent to gardens. In late spring females deposit 1-6 eggs daily within the stems and larger veins of the leaves. Hatching occurs in 6-9 days, and the young nymphs molt 5 times before they become fully grown adults. White cast skins shed by the molting nymphs can often be found attached to the underside of damaged leaves. The period from egg to adult is about three weeks. Several overlapping generations may be completed during the growing season.
Leafhopper Control
Remove garden trash and other debris shortly after harvest to reduce over-wintering sites.
Floating row covers can be used as a physical barrier to keep leafhoppers from damaging plants.
Commercially available beneficial insects, such as ladybugs, lacewing and minute pirate bugs, are all voracious predators of both the egg and young larval stage.
Apply diatomaceous earth to plants and/or spot treat with insecticidal soap to keep pest populations under control. Thorough coverage of both upper and lower infested leaves is necessary for effective control.
If pest levels become intolerable, spot treat with potent, fast-acting organic insecticides as a last resort.
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文章
Dummer. ゛☀
2017年09月14日
The imported Viburnum Leaf Beetle (VLB), a native of both Europe and Asia, was first spotted in North America in 1978, in the Ottawa-Hull region of Canada. Since then, it has been making its way south from Canada into the U.S. Viburnums have always been considered exceptionally pest free landscape plants, but this new pest is challenging that assumption. The VLB is a close relative of the more common elm leaf beetle and can very quickly strip the leaves from viburnums plants.
Both the larva and the adult beetle feed on viburnum leaves, skeletonizing them in a relatively short time. Initial infestations will not kill the plants, but defoliation for 2 - 3 consecutive years can be fatal.
What Does the Viburnum Leaf Beetle Look Like?
Viburnum leaf beetles are rather bland looking for an exotic pest and can be easily missed. The adults are about a 1/4 inch long (4.5 to 6.5 mm) and a dull brown, as are the tiny eggs. The larvae are a greenish-yellow, somewhat blending in with the foliage. They grow to about ½ inch long. Invasive.org has some great pictures of the various stages of the viburnum leaf beetle, which will help with identification.
Does the Viburnum Leaf Beetle Feed On All types of Viburnum?
Currently, the VLB has three favorite varieties of viburnum plants:
European highbush cranberry (Viburnum opulus)
Wayfaringtree viburnum (Viburnum lantana)
Rafinesque viburnum (Viburnum rafinesquianum)
Viburnum Leaf Beetle Lifecycle
The beetles overwinter as eggs deposited in the branches. They hatch in May and the larvae then feeds on the new leaves. Since the newly emerged larvae are so small, the first signs of injury may be missed, as the damage can appear as holes no larger than pin holes. Within a month, skeletonizing will be hard to miss.
It takes about 8-10 weeks for the VLB to go from egg to adult.
Sometime in June, the larvae will make their way to the ground, where they will pupate in the soil. The adult VLB emerges in the latter part of July and continues feeding on viburnums. The female VLB can lay eggs from late summer to the first frost, sometimes as many as 500 eggs per season. She chews holes in the new growth of viburnum and lays eggs in each hole. The holes are then covered with a mix of chewed twig and excrement, making them harder to notice. However, the holes will be made in a straight line on the underside of the twig.
How to Control Viburnum Leaf Beetle Damage
The best protection against VLB is to plant resistant varieties. These include some of the most popular landscape viburnums, including:
Doublefile viburnum (Viburnum plicatum)
Korean Spice viburnum (Viburnum carlesii)
Leatherleaf viburnum (Viburnum rhytidophyllum)
Cornell’s VLB Citizen Science lists those most resistant and varieties to avoid or monitor closely.
If you already have viburnums in your landscape, keep a close watch. In the early spring, before the eggs hatch in May, closely examine the small twigs from the previous year’s growth for egg laying holes and scars.
Warmer temperatures will cause the holes to swell and the caps may fall off. You will need to prune out and destroy all infested wood before the eggs hatch.
A the new leaves begin to open, check both sides of the leaves for larvae and again prune and destroy infested plant parts. Chemical pesticides are most effective when applied while the larvae are young. Adults tend to fly away or drop to the ground when disturbed. Check with your local Extension Service for recommended pesticides.
Both the larva and the adult beetle feed on viburnum leaves, skeletonizing them in a relatively short time. Initial infestations will not kill the plants, but defoliation for 2 - 3 consecutive years can be fatal.
What Does the Viburnum Leaf Beetle Look Like?
Viburnum leaf beetles are rather bland looking for an exotic pest and can be easily missed. The adults are about a 1/4 inch long (4.5 to 6.5 mm) and a dull brown, as are the tiny eggs. The larvae are a greenish-yellow, somewhat blending in with the foliage. They grow to about ½ inch long. Invasive.org has some great pictures of the various stages of the viburnum leaf beetle, which will help with identification.
Does the Viburnum Leaf Beetle Feed On All types of Viburnum?
Currently, the VLB has three favorite varieties of viburnum plants:
European highbush cranberry (Viburnum opulus)
Wayfaringtree viburnum (Viburnum lantana)
Rafinesque viburnum (Viburnum rafinesquianum)
Viburnum Leaf Beetle Lifecycle
The beetles overwinter as eggs deposited in the branches. They hatch in May and the larvae then feeds on the new leaves. Since the newly emerged larvae are so small, the first signs of injury may be missed, as the damage can appear as holes no larger than pin holes. Within a month, skeletonizing will be hard to miss.
It takes about 8-10 weeks for the VLB to go from egg to adult.
Sometime in June, the larvae will make their way to the ground, where they will pupate in the soil. The adult VLB emerges in the latter part of July and continues feeding on viburnums. The female VLB can lay eggs from late summer to the first frost, sometimes as many as 500 eggs per season. She chews holes in the new growth of viburnum and lays eggs in each hole. The holes are then covered with a mix of chewed twig and excrement, making them harder to notice. However, the holes will be made in a straight line on the underside of the twig.
How to Control Viburnum Leaf Beetle Damage
The best protection against VLB is to plant resistant varieties. These include some of the most popular landscape viburnums, including:
Doublefile viburnum (Viburnum plicatum)
Korean Spice viburnum (Viburnum carlesii)
Leatherleaf viburnum (Viburnum rhytidophyllum)
Cornell’s VLB Citizen Science lists those most resistant and varieties to avoid or monitor closely.
If you already have viburnums in your landscape, keep a close watch. In the early spring, before the eggs hatch in May, closely examine the small twigs from the previous year’s growth for egg laying holes and scars.
Warmer temperatures will cause the holes to swell and the caps may fall off. You will need to prune out and destroy all infested wood before the eggs hatch.
A the new leaves begin to open, check both sides of the leaves for larvae and again prune and destroy infested plant parts. Chemical pesticides are most effective when applied while the larvae are young. Adults tend to fly away or drop to the ground when disturbed. Check with your local Extension Service for recommended pesticides.
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文章
Dummer. ゛☀
2017年09月14日
Leaf tip browning is an annoying condition that commonly affects certain types of houseplants. Spider plants, tropical plants, and those with long, strappy leaves are especially susceptible. The main difficulty when confronting leaf tip burn is to remember that it's a symptom of a larger problem (usually a cultural issue), as opposed to a condition in itself. So once your plant has burned leaf tips or margins, there's no way to reverse the damage at that wounded location.
The only thing to do is correct the underlying problem and hope the plant continues its healthy growth.
The other problem with a leaf-tip burn is figuring out which of the possible factors may be causing it. Is it the water? Your fertilizer habits? The humidity? You might not know right away, so the best idea is, to begin with, the most likely condition, change it to the extent possible, and wait to see what happens. If new growth is unaffected or the scorching stops, you've figured it out. If it continues, then move on to the next condition and work on that.
Ideally, you'll catch leaf-tip burn early enough that the plant's appearance won't be completely ruined.
These are the factors that can potentially cause leaf-tip burn:
Watering issues. Leaf scorching can be a sign of erratic or insufficient watering or low humidity. It is especially true for tropical plants, which dislike the parched conditions in most centrally heated homes in the winter. These plants are evolved to luxuriate in humidity levels that range between 60 and 100 percent in their rainforest homes. A winter-time home can easily go to 20% humidity, which can cause leaf scorching. The solution is to raise the humidity—mist the plants, use a pebble tray, or relocate the plant to an area with higher humidity such as the kitchen or bathroom. Also, remember that plants with strappy leaves have a greater challenge to move water from the roots to the ends of the leaves, so these plants are likely to show leaf-tip scorching faster than plants with shorter leaves. Finally, if you suspect your water is highly alkaline (a pH above 7), consider finding a more neutral water source. Plants prefer a slightly acidic environment.
Fertilizer issues. Fertilizer salts can cause leaf scorching, especially if large doses are fertilizer are applied. If you notice scorching on your plants shortly after feeding a heavy dose of fertilizer, it might be a problem with your fertilizer. Flush the soil with clean water several times to remove accumulated fertilizer salts and be more careful in the future.
Fluoride. The idea that fluoride can damage houseplants has taken off recently, but the truth is that fluoride damage is usually limited to plants in the Dracaena family. These plants are susceptible to fluoride damage over the long-term, so if you're experiencing leaf burn in a Dracaena species, switch to un-fluoridated water. If the plant isn't dracaena, it's unlikely that fluoride is the issue.
Cold damage. Closely related to water stress, many houseplants aren't acclimated to cold, drafty conditions (by a winter window, for instance). Cold damage often shows up in the extremities first, meaning the leaf margins and leaf tips. If your tropical plants suffer from leaf scorching during the winter months, try to raise the temperature (and humidity, most likely) around them.
Sun damage. Sun damage usually shows up as yellowing of the whole leaf, or even scorched spots on the leaves. Nevertheless, if your plant has recently been subjected to a change of direct light it's receiving, this could be the culprit.
Chemical damage. It is less likely to result in leaf-scorching, but it's possible. Household pesticides and cleaning chemicals can burn plants in some cases, so be aware of what you're using on your plants.
Ultimately, a leaf-tip burn is almost always a cultural problem—fungal and bacterial diseases are typically more widespread across the leaf surface and usually involve the stem as well. So the best way to correct leaf-tip burn and margin scorching is to ask what cultural conditions might be causing the condition, then making an effort to fix them.
The only thing to do is correct the underlying problem and hope the plant continues its healthy growth.
The other problem with a leaf-tip burn is figuring out which of the possible factors may be causing it. Is it the water? Your fertilizer habits? The humidity? You might not know right away, so the best idea is, to begin with, the most likely condition, change it to the extent possible, and wait to see what happens. If new growth is unaffected or the scorching stops, you've figured it out. If it continues, then move on to the next condition and work on that.
Ideally, you'll catch leaf-tip burn early enough that the plant's appearance won't be completely ruined.
These are the factors that can potentially cause leaf-tip burn:
Watering issues. Leaf scorching can be a sign of erratic or insufficient watering or low humidity. It is especially true for tropical plants, which dislike the parched conditions in most centrally heated homes in the winter. These plants are evolved to luxuriate in humidity levels that range between 60 and 100 percent in their rainforest homes. A winter-time home can easily go to 20% humidity, which can cause leaf scorching. The solution is to raise the humidity—mist the plants, use a pebble tray, or relocate the plant to an area with higher humidity such as the kitchen or bathroom. Also, remember that plants with strappy leaves have a greater challenge to move water from the roots to the ends of the leaves, so these plants are likely to show leaf-tip scorching faster than plants with shorter leaves. Finally, if you suspect your water is highly alkaline (a pH above 7), consider finding a more neutral water source. Plants prefer a slightly acidic environment.
Fertilizer issues. Fertilizer salts can cause leaf scorching, especially if large doses are fertilizer are applied. If you notice scorching on your plants shortly after feeding a heavy dose of fertilizer, it might be a problem with your fertilizer. Flush the soil with clean water several times to remove accumulated fertilizer salts and be more careful in the future.
Fluoride. The idea that fluoride can damage houseplants has taken off recently, but the truth is that fluoride damage is usually limited to plants in the Dracaena family. These plants are susceptible to fluoride damage over the long-term, so if you're experiencing leaf burn in a Dracaena species, switch to un-fluoridated water. If the plant isn't dracaena, it's unlikely that fluoride is the issue.
Cold damage. Closely related to water stress, many houseplants aren't acclimated to cold, drafty conditions (by a winter window, for instance). Cold damage often shows up in the extremities first, meaning the leaf margins and leaf tips. If your tropical plants suffer from leaf scorching during the winter months, try to raise the temperature (and humidity, most likely) around them.
Sun damage. Sun damage usually shows up as yellowing of the whole leaf, or even scorched spots on the leaves. Nevertheless, if your plant has recently been subjected to a change of direct light it's receiving, this could be the culprit.
Chemical damage. It is less likely to result in leaf-scorching, but it's possible. Household pesticides and cleaning chemicals can burn plants in some cases, so be aware of what you're using on your plants.
Ultimately, a leaf-tip burn is almost always a cultural problem—fungal and bacterial diseases are typically more widespread across the leaf surface and usually involve the stem as well. So the best way to correct leaf-tip burn and margin scorching is to ask what cultural conditions might be causing the condition, then making an effort to fix them.
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文章
Dummer. ゛☀
2017年09月14日
What Is Azalea Leaf Gall?
First of all, let's consider what a "gall" is, in general, in the context of horticulture. A gall is a tumor-like eruption in plant tissue. A number of different plants are susceptible. The two types of plants upon which I most commonly find galls are:
Oak trees
Goldenrod
A gall represents the plant's reaction to damage caused by an invading agent. In the case of azalea galls, that agent is a fungus (see below).
But there are other agents that cause galls to develop on other plants. For example, one master gardener has written about the leaf galls caused by insects on various trees.
Regarding azalea leaf galls, specifically, you will notice two different phases (which may be present at the same time on the same plant, as in my picture):
In phase one, the swollen leaf tissue is waxy and most often pale green.
In phase two, it is a gray blob (and more recognizable to the beginner as some sort of fungus).
Even the flowers on azalea bushes can be infested with galls.
What to Do About Azalea Leaf Galls
First of all, take solace in the fact that their bark is worse than their bite. As alien-looking and repulsive as azalea leaf galls are, they are not considered overly serious. They are caused by the fungus, Exobasidium vaccinii. Pick off the leaves where the azalea leaf galls occur and dispose of them properly.
Do not put them in the compost bin, and do not leave them lying around on the ground, lest the fungus spread to other branches.
For preventive care, avoid letting the soil become compacted around your azaleas. You can accomplish this in a number of ways, including by:
Working ample amounts of humus into the soil
Applying landscape mulch around the plants
Furthermore, as is usually the case when dealing with fungus prevention, make it a point to apply water to your azalea shrubs down at ground level, rather than spraying from above. The latter practice gets the foliage all wet, which is an open invitation to fungi.
Having said all that, overall, I have found the amount of time I need to put into azalea care to be relatively minimal here in the Northeastern U.S. Care has consisted mainly of occasionally spraying neem oil on my Gibraltar azalea to kill aphids.
First of all, let's consider what a "gall" is, in general, in the context of horticulture. A gall is a tumor-like eruption in plant tissue. A number of different plants are susceptible. The two types of plants upon which I most commonly find galls are:
Oak trees
Goldenrod
A gall represents the plant's reaction to damage caused by an invading agent. In the case of azalea galls, that agent is a fungus (see below).
But there are other agents that cause galls to develop on other plants. For example, one master gardener has written about the leaf galls caused by insects on various trees.
Regarding azalea leaf galls, specifically, you will notice two different phases (which may be present at the same time on the same plant, as in my picture):
In phase one, the swollen leaf tissue is waxy and most often pale green.
In phase two, it is a gray blob (and more recognizable to the beginner as some sort of fungus).
Even the flowers on azalea bushes can be infested with galls.
What to Do About Azalea Leaf Galls
First of all, take solace in the fact that their bark is worse than their bite. As alien-looking and repulsive as azalea leaf galls are, they are not considered overly serious. They are caused by the fungus, Exobasidium vaccinii. Pick off the leaves where the azalea leaf galls occur and dispose of them properly.
Do not put them in the compost bin, and do not leave them lying around on the ground, lest the fungus spread to other branches.
For preventive care, avoid letting the soil become compacted around your azaleas. You can accomplish this in a number of ways, including by:
Working ample amounts of humus into the soil
Applying landscape mulch around the plants
Furthermore, as is usually the case when dealing with fungus prevention, make it a point to apply water to your azalea shrubs down at ground level, rather than spraying from above. The latter practice gets the foliage all wet, which is an open invitation to fungi.
Having said all that, overall, I have found the amount of time I need to put into azalea care to be relatively minimal here in the Northeastern U.S. Care has consisted mainly of occasionally spraying neem oil on my Gibraltar azalea to kill aphids.
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文章
Dummer. ゛☀
2017年09月14日
Many homeowners who landscape their properties with trees are taken aback when they spot infestations of leaf gall on their favorite specimens. Appearing as little bumps on the foliage of a tree (as if your plant were breaking out with some weird type of acne), these disfiguring eruptions look terrible. But how bad are they for the long-term health of your plant? And what is the cause behind them?
What Causes Leaf Gall? How Big a Problem Is It?
"We have a river birch tree which is about three years old," writes one reader. "Suddenly this summer, small bumps are appearing on some of the leaves. Is this a disease and can it be stopped?"
What this reader is reporting is a case of leaf gall. Those small bumps are caused by an insect that eats or lays eggs on the plant's foliage. One Master Gardener explains that the gall "is the plant's response to the resulting irritation," drawing an analogy to what happens to the human body after a bug such as a mosquito bites us: a bump is left behind. She notes that, while galls are rarely fatal, "they may cause early leaf drop," but she adds that a healthy, mature tree will be able to cope with such leaf drop by producing new foliage and that a serious problem should only result if the galls keep coming back for several years in a row.
What's the Solution?
The bad news is that, once you spot these bumps, the damage has already been done.
You can't spray to get rid of the bumps that are currently infesting your tree's foliage: you are stuck with them for the present year. As the same source notes, however, if leaf gall is a recurring problem for you, you can spray in early spring to get a jump on the insects. However, do note that you can't just spray willy-nilly: the spray that you use must target the particular insect that is causing the leaf galls to form.
One problem with spraying, however, as pointed out by the Missouri Botanical Garden (MBOT), is that you will be killing beneficial insects, too -- insects that may actually be able to help you control your leaf-gall problem over the long haul (by killing the insects who cause the galls). They emphasize that spraying is a preventive measure, and that a certified arborist should be employed for the job (because it takes great skill "to identify the gall-producing organism").
The good news, again, is that leaf gall is typically not considered very dangerous (either in general or to river birch trees, specifically). In fact, MBOT asserts that a leaf studded with these ugly growths is still "usually able to carry out photosynthesis at near normal levels."
In addition to birches, trees known to be susceptible to developing leaf galls include:
Elms
Maples
Oaks
What Causes Leaf Gall? How Big a Problem Is It?
"We have a river birch tree which is about three years old," writes one reader. "Suddenly this summer, small bumps are appearing on some of the leaves. Is this a disease and can it be stopped?"
What this reader is reporting is a case of leaf gall. Those small bumps are caused by an insect that eats or lays eggs on the plant's foliage. One Master Gardener explains that the gall "is the plant's response to the resulting irritation," drawing an analogy to what happens to the human body after a bug such as a mosquito bites us: a bump is left behind. She notes that, while galls are rarely fatal, "they may cause early leaf drop," but she adds that a healthy, mature tree will be able to cope with such leaf drop by producing new foliage and that a serious problem should only result if the galls keep coming back for several years in a row.
What's the Solution?
The bad news is that, once you spot these bumps, the damage has already been done.
You can't spray to get rid of the bumps that are currently infesting your tree's foliage: you are stuck with them for the present year. As the same source notes, however, if leaf gall is a recurring problem for you, you can spray in early spring to get a jump on the insects. However, do note that you can't just spray willy-nilly: the spray that you use must target the particular insect that is causing the leaf galls to form.
One problem with spraying, however, as pointed out by the Missouri Botanical Garden (MBOT), is that you will be killing beneficial insects, too -- insects that may actually be able to help you control your leaf-gall problem over the long haul (by killing the insects who cause the galls). They emphasize that spraying is a preventive measure, and that a certified arborist should be employed for the job (because it takes great skill "to identify the gall-producing organism").
The good news, again, is that leaf gall is typically not considered very dangerous (either in general or to river birch trees, specifically). In fact, MBOT asserts that a leaf studded with these ugly growths is still "usually able to carry out photosynthesis at near normal levels."
In addition to birches, trees known to be susceptible to developing leaf galls include:
Elms
Maples
Oaks
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文章
Dummer. ゛☀
2017年09月14日
Have you ever picked up a leave that was dotted with bumps or had long protrusions dangling from it? Chances are these are leaf galls.
What are Leaf Galls
Leaf galls are a frightening sight, but are not usually as serious as they appear. These bumps and deformities are usually the result of feeding by insects or some other foreign organism such as bacteria, fungi, mites, nematodes, and even viruses.
These organisms are usually not still on the plant leaf. The gall itself is actually the plant’s response to the irritation. It’s not unlike the bump you get when an insect feeds on you, expect the leaf gall is not going to go away.
Despite appearances, the insect is not living in the gall. In fact, it is very likely that once you notice the galls the insects have moved on. Before they do, they can do a lot of cosmetic damage to many plants and in particular trees. Galls can also form on stems and flowers, however leaf galls seem to be the ost prominent and get the most notice.
It is the fresh new growth that are attacked by the insects and other organisms and then produce the galls. Mature leaves are rarely affected. However many common trees are susceptible to leaf galls, especially when first leafing out in the spring. Maple, oak, elm, hackberry and others each are favored by a different insect that causes unsightly and intimidating galls.
Damage will be greater following a mild winter, since more insects have survived and are hungry. Galls won’t usually kill a tree, but they may cause early leaf drop. A healthy tree will send out new growth and recover.
What Can You Do About Leaf Galls?
Since the damage occurred before the gall formed, treatment is rarely recommended.
If you have a serous reoccurring insect problems, you can spray your tree in early spring, to lessen the severity of the damage. Contact your local extension office for specific guidelines and recommendations in your area. But if you're patient, nature may take care of the problem for you. Gall making insects tend to attract their own predators.
One way leaf galls can cause a serious problem for trees is that their formation requires energy and nutrients from the tree, which can stress and weaken the tree itself, as it is coming out of dormancy in the spring. This can happen when there is an unusually high concentration of galls on the plant or when the plant is attacked and galls are produced several years in a row. For this reason, you should not ignore the presence of galls entirely. If this is the case, you should consider finding out what organism is causing the galls and treat for it the following spring, to prevent further stress and damage.
What are Leaf Galls
Leaf galls are a frightening sight, but are not usually as serious as they appear. These bumps and deformities are usually the result of feeding by insects or some other foreign organism such as bacteria, fungi, mites, nematodes, and even viruses.
These organisms are usually not still on the plant leaf. The gall itself is actually the plant’s response to the irritation. It’s not unlike the bump you get when an insect feeds on you, expect the leaf gall is not going to go away.
Despite appearances, the insect is not living in the gall. In fact, it is very likely that once you notice the galls the insects have moved on. Before they do, they can do a lot of cosmetic damage to many plants and in particular trees. Galls can also form on stems and flowers, however leaf galls seem to be the ost prominent and get the most notice.
It is the fresh new growth that are attacked by the insects and other organisms and then produce the galls. Mature leaves are rarely affected. However many common trees are susceptible to leaf galls, especially when first leafing out in the spring. Maple, oak, elm, hackberry and others each are favored by a different insect that causes unsightly and intimidating galls.
Damage will be greater following a mild winter, since more insects have survived and are hungry. Galls won’t usually kill a tree, but they may cause early leaf drop. A healthy tree will send out new growth and recover.
What Can You Do About Leaf Galls?
Since the damage occurred before the gall formed, treatment is rarely recommended.
If you have a serous reoccurring insect problems, you can spray your tree in early spring, to lessen the severity of the damage. Contact your local extension office for specific guidelines and recommendations in your area. But if you're patient, nature may take care of the problem for you. Gall making insects tend to attract their own predators.
One way leaf galls can cause a serious problem for trees is that their formation requires energy and nutrients from the tree, which can stress and weaken the tree itself, as it is coming out of dormancy in the spring. This can happen when there is an unusually high concentration of galls on the plant or when the plant is attacked and galls are produced several years in a row. For this reason, you should not ignore the presence of galls entirely. If this is the case, you should consider finding out what organism is causing the galls and treat for it the following spring, to prevent further stress and damage.
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Dummer. ゛☀
2017年09月14日
A reader wrote in about newly planted Bradford pear trees, saying that they had borne the brunt of high winds for a couple of days. The Bradford pears on the property developed brown leaves; they suffered from leaf wilt and looked dead, despite the homeowner's keeping the ground damp. So what, if anything, can be done in cases like this? 
Windy Weather Only Partly Responsible for Leaf Wilt and Related Diseases
Bradford pears and other trees that have just been transplanted experience transplant shock in a great many cases.
Their roots have been disrupted, and they can be quick to show their displeasure. If someone picked you up, carried you out of your home and plopped you down on a strange property, you probably would be none too happy, either.
In its state of shock, the damaged Bradford pear tree's roots can't send water up to the leaves as they normally would. Pounding winds make matters worse. One result can be leaf wilt. Other plant problems can be caused by these conditions, as well, on deciduous trees. The Purdue University Cooperative Extension Service lists some of them:
Leaf scorch.
Yellowing of the leaves.
Leaf rolling.
Curling of the leaves.
Purdue observes that, at its onset, leaf scorch is indicated by the coloration of the "tissue between the veins or along the margins of leaves" becoming yellow, and that, as the problem progresses, this tissue becomes dry, resulting in a brown color.
What Is the Treatment for Leaf Wilt on Bradford Pear Trees?
What can you do to revive Bradford pear trees that have fallen prey to leaf wilt?
Sadly, there is not much at this stage of the game that you can do. This is a case where prevention before the fact is more effective than treatment after the fact. For future reference, windbreaks could have minimized wilt damage, but it is rather late for that once the wilting has taken place.
One should, however, emphasize what not to do: Do not fertilize.
By feeding the plants, you would be encouraging additional leaf growth. That is not something that you want at this point. The root system can't support the canopy as it is, as said above; so there is no sense in adding to its burden.
Provide the Bradford pear trees with irrigation regularly. Other than that, all you can do is exercise patience and see if they revive from their transplant shock and subsequent leaf wilt.
Transplant Shock and "Bare-Root" Plants
As the same Purdue source points out, "Bare root trees and shrubs are most susceptible to transplant shock. Such 'stressed' plants are very fragile and are more susceptible to other stress factors." If you are used to buying plants at garden centers growing in flats or pots (or balled-and-burlapped, in the case of trees), then that terminology, "bare-root" might leave you scratching your head. But the definition of this term is surprisingly straightforward:
Bare-root plants are shipped with no soil "clothing" their roots. When you buy shrubs at the garden center, they may well come in containers, but when you order them from garden catalogs, they will often arrive as bare-root plants.
You may wonder if shipping a plant with no soil on its roots is harmful to the plant.
The fact is, not just any plant can be shipped bare-root. But certain plants -- for example, rose bushes -- can survive this method of transport in a sort of dormancy. But do not push your luck! Planting bare-root plants as soon as possible after they have arrived by mail is recommended. And if you cannot plant immediately, at least place the roots in water.
As faithful as you might be in following these instructions, though, there is simply a lot that can go wrong when installing new plants -- whether it be bare-root or not. One of the "stress factors" cited by Purdue is drainage problems. To improve the chances that your new Bradford pear tree (or other plant) will survive and thrive, ensure that the soil under and around your plant's roots drains well, so that water won't collect and rot the roots.
Windy Weather Only Partly Responsible for Leaf Wilt and Related Diseases
Bradford pears and other trees that have just been transplanted experience transplant shock in a great many cases.
Their roots have been disrupted, and they can be quick to show their displeasure. If someone picked you up, carried you out of your home and plopped you down on a strange property, you probably would be none too happy, either.
In its state of shock, the damaged Bradford pear tree's roots can't send water up to the leaves as they normally would. Pounding winds make matters worse. One result can be leaf wilt. Other plant problems can be caused by these conditions, as well, on deciduous trees. The Purdue University Cooperative Extension Service lists some of them:
Leaf scorch.
Yellowing of the leaves.
Leaf rolling.
Curling of the leaves.
Purdue observes that, at its onset, leaf scorch is indicated by the coloration of the "tissue between the veins or along the margins of leaves" becoming yellow, and that, as the problem progresses, this tissue becomes dry, resulting in a brown color.
What Is the Treatment for Leaf Wilt on Bradford Pear Trees?
What can you do to revive Bradford pear trees that have fallen prey to leaf wilt?
Sadly, there is not much at this stage of the game that you can do. This is a case where prevention before the fact is more effective than treatment after the fact. For future reference, windbreaks could have minimized wilt damage, but it is rather late for that once the wilting has taken place.
One should, however, emphasize what not to do: Do not fertilize.
By feeding the plants, you would be encouraging additional leaf growth. That is not something that you want at this point. The root system can't support the canopy as it is, as said above; so there is no sense in adding to its burden.
Provide the Bradford pear trees with irrigation regularly. Other than that, all you can do is exercise patience and see if they revive from their transplant shock and subsequent leaf wilt.
Transplant Shock and "Bare-Root" Plants
As the same Purdue source points out, "Bare root trees and shrubs are most susceptible to transplant shock. Such 'stressed' plants are very fragile and are more susceptible to other stress factors." If you are used to buying plants at garden centers growing in flats or pots (or balled-and-burlapped, in the case of trees), then that terminology, "bare-root" might leave you scratching your head. But the definition of this term is surprisingly straightforward:
Bare-root plants are shipped with no soil "clothing" their roots. When you buy shrubs at the garden center, they may well come in containers, but when you order them from garden catalogs, they will often arrive as bare-root plants.
You may wonder if shipping a plant with no soil on its roots is harmful to the plant.
The fact is, not just any plant can be shipped bare-root. But certain plants -- for example, rose bushes -- can survive this method of transport in a sort of dormancy. But do not push your luck! Planting bare-root plants as soon as possible after they have arrived by mail is recommended. And if you cannot plant immediately, at least place the roots in water.
As faithful as you might be in following these instructions, though, there is simply a lot that can go wrong when installing new plants -- whether it be bare-root or not. One of the "stress factors" cited by Purdue is drainage problems. To improve the chances that your new Bradford pear tree (or other plant) will survive and thrive, ensure that the soil under and around your plant's roots drains well, so that water won't collect and rot the roots.
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Dummer. ゛☀
2017年09月14日
A reader wrote in about newly transplanted weigela shrubs suffering from leaf-wilt, noting that it had been very windy in his area of late. The weigela leaves wilted in spite of his keeping the ground damp. So are the plants dead? What, if anything, can be done for plants with wilted leaves?
See my answer below:
Why Do Leaves Wilt?
It is important to realize that not all leaf-wilt is created equal. Rather, there are a number of different reasons why leaves wilt.
Before taking any action, you must determine which of these reasons applies to your wilting plant:
Damaged roots
Lack of water
Fungal infection
Plant roots draw water out of the ground and send it up through the above-ground parts of the plant. If the roots are damaged, the flow of water to the leaves is reduced. Wilting leaves can result.
Roots can sustain damage from a number of sources, including from:
Transplant shock
Physical injury from digging (while cultivating around the plant, etc.)
Overwatering
It is common when transplanting shrubs, including weigela shrubs, to cause transplant shock. The disturbed roots find it difficult to nourish the leaves with sufficient water in their damaged state, as the roots of a healthy, established shrub would. High winds simply exacerbate the problem: they have a drying effect that further robs the leaves of moisture. The result is leaf-wilt.
Direct Answer to the Reader's Question
Assuming that transplant shock is the reason behind the wilting leaves in your case, the positive actions you can take to help the weigela shrubs, at this point, are limited.
Unfortunately, only forethought can prevent (or, at least, minimize) the effects of transplant shock. Windbreaks would have been effective (to shelter your weigela from drying winds). Likewise, you can prevent or minimize leaf-wilt by picking the best times to transplant. By avoiding transplanting at the hottest times of the year, you put less stress on the plants' root systems, thereby keeping them healthier.
But the good news is that your weigela bushes are not dead: they just need time to recover.
Here is what not to do: do not fertilize. Fertilizing would foster extra leaf growth -- which you do not want, since the weigela shrubs' disturbed roots are already struggling to support the current amount of foliage.
Do water your weigela shrubs when the soil is dry, but do not overwater. When a plant's roots have been damaged (from transplant shock or any other source), they have to be given time to heal. Flooding a root system with water when that system is incapable of absorbing the water is, at best, useless and, at worst, counterproductive.
Root damage can also be caused by digging too close to your plant while cultivating. For example, some gardeners will dig around a plant to remove weeds and accidentally sever roots in the process. You can largely avoid this problem by mulching. Others make the mistake of cutting into root systems when working compost or manure into the soil. Here the solution is to apply, instead, a compost tea or manure tea, which involves no digging. Again, once the damage has occurred, resist the temptation to combat the resulting leaf-wilt by overwatering (which will do no good).
Finally, overwatering, itself can damage plant roots. The roots essentially rot and lose their ability to take up water. Adding more water in such a case can be like adding fuel to a fire.
What if the Reason for Leaf-Wilt Is Not Root Damage?
I have already mentioned a couple of alternate reasons for leaf-wilt, above. One is a soil fungus. Weigela shrubs are, in fact, one of the plants susceptible to the fungus, Verticillium wilt. According the University of Minnesota Extension (UVM), one way to identify this fungus is to look for "a scorched appearance" on leaf margins. To combat Verticillium wilt, UVM recommends selecting resistant plants and providing basic care (proper watering, fertilizing, etc.).
That leaves one last cause of leaf-wilt, the one that most gardeners think of immediately: namely, lack of water.
Yes, sometimes the reason is no more complicated than that the soil has dried out around your plant. If you do not see scorched leaf margins on your plant and have no reason to believe that root damage has occurred, you're lucky. Solving the problem is as easy as giving the plant a drink of water.
See my answer below:
Why Do Leaves Wilt?
It is important to realize that not all leaf-wilt is created equal. Rather, there are a number of different reasons why leaves wilt.
Before taking any action, you must determine which of these reasons applies to your wilting plant:
Damaged roots
Lack of water
Fungal infection
Plant roots draw water out of the ground and send it up through the above-ground parts of the plant. If the roots are damaged, the flow of water to the leaves is reduced. Wilting leaves can result.
Roots can sustain damage from a number of sources, including from:
Transplant shock
Physical injury from digging (while cultivating around the plant, etc.)
Overwatering
It is common when transplanting shrubs, including weigela shrubs, to cause transplant shock. The disturbed roots find it difficult to nourish the leaves with sufficient water in their damaged state, as the roots of a healthy, established shrub would. High winds simply exacerbate the problem: they have a drying effect that further robs the leaves of moisture. The result is leaf-wilt.
Direct Answer to the Reader's Question
Assuming that transplant shock is the reason behind the wilting leaves in your case, the positive actions you can take to help the weigela shrubs, at this point, are limited.
Unfortunately, only forethought can prevent (or, at least, minimize) the effects of transplant shock. Windbreaks would have been effective (to shelter your weigela from drying winds). Likewise, you can prevent or minimize leaf-wilt by picking the best times to transplant. By avoiding transplanting at the hottest times of the year, you put less stress on the plants' root systems, thereby keeping them healthier.
But the good news is that your weigela bushes are not dead: they just need time to recover.
Here is what not to do: do not fertilize. Fertilizing would foster extra leaf growth -- which you do not want, since the weigela shrubs' disturbed roots are already struggling to support the current amount of foliage.
Do water your weigela shrubs when the soil is dry, but do not overwater. When a plant's roots have been damaged (from transplant shock or any other source), they have to be given time to heal. Flooding a root system with water when that system is incapable of absorbing the water is, at best, useless and, at worst, counterproductive.
Root damage can also be caused by digging too close to your plant while cultivating. For example, some gardeners will dig around a plant to remove weeds and accidentally sever roots in the process. You can largely avoid this problem by mulching. Others make the mistake of cutting into root systems when working compost or manure into the soil. Here the solution is to apply, instead, a compost tea or manure tea, which involves no digging. Again, once the damage has occurred, resist the temptation to combat the resulting leaf-wilt by overwatering (which will do no good).
Finally, overwatering, itself can damage plant roots. The roots essentially rot and lose their ability to take up water. Adding more water in such a case can be like adding fuel to a fire.
What if the Reason for Leaf-Wilt Is Not Root Damage?
I have already mentioned a couple of alternate reasons for leaf-wilt, above. One is a soil fungus. Weigela shrubs are, in fact, one of the plants susceptible to the fungus, Verticillium wilt. According the University of Minnesota Extension (UVM), one way to identify this fungus is to look for "a scorched appearance" on leaf margins. To combat Verticillium wilt, UVM recommends selecting resistant plants and providing basic care (proper watering, fertilizing, etc.).
That leaves one last cause of leaf-wilt, the one that most gardeners think of immediately: namely, lack of water.
Yes, sometimes the reason is no more complicated than that the soil has dried out around your plant. If you do not see scorched leaf margins on your plant and have no reason to believe that root damage has occurred, you're lucky. Solving the problem is as easy as giving the plant a drink of water.
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0
文章
Dummer. ゛☀
2017年09月13日
Description
Black spot is basically what it sounds like: roundish black spots on leaf surfaces. The spots grow over time, and the foliage around the spot yellows. Eventually, the entire leaf falls off.
Damage to Plants
The issue with black spot is that the defoliation that occurs when the fungus is allowed to get out of control weakens the plant. And not just for the current growing season, but for the next season as well.
The main function of plant foliage is to absorb energy from the sun and perform photosynthesis. If your plant loses all or most of its leaves to black spot, it will be unable to collect and store energy for the winter, as well as for the burst of growth that occurs in spring. You'll see weaker growth and reduced bloom in the season following severe black spot damage.
Disease Life Cycle
Black spot spores overwinter on infected foliage and canes, including infected foliage that has fallen and been left on the ground. In spring, spores are splashed up onto newly emerging foliage during rains or irrigation. Once the weather begins to stay consistently warm and humid, the spores germinate and infect the plant within one day. Visible symptoms (black spot and some yellowing) will be evident within five days, and it will produce and spread new spores within ten days. The new spores will infect other parts of the plant, or be carried on the wind to any other nearby rose bushes.
Treatment and Prevention
There are several organic ways to control black spot. Most of them rely on regular monitoring and upkeep. None of them are difficult and can be accomplished while you're admiring your roses.
Plant roses in full sun. If you give your roses a spot where they receive a full six to eight hours of sun per day, you'll not only have plants that grow more robustly, but also plants that are more able to resist black spot. Black spot loves moisture, and, in shade, water evaporates much more slowly. In full sun, evaporation happens more quickly, which not only helps prevent black spot, but other fungal diseases as well.
Plant roses in an area with good air circulation. This accomplishes the same thing as planting in an area with direct sunlight: moisture evaporates more quickly. In addition, with plenty of air circulation, hopefully breezes will blow any newly-germinated black spot spores away from your roses. In an area with poor air circulation, the spores have nowhere to go but back onto your plant and the surrounding soil.: moisture evaporates more quickly. In addition, with plenty of air circulation, hopefully breezes will blow any newly-germinated black spot spores away from your roses. In an area with poor air circulation, the spores have nowhere to go but back onto your plant and the surrounding soil.
Water correctly. Try to avoid overhead irrigation, which wets the foliage. It's more efficient to water at ground level anyway; you lose less water to evaporation. Also, avoid watering late in the day. Water evaporates much slower in cooler evening and nighttime temperatures.
Remove leaves that show signs of infection. As soon as you see black spot on your rose foliage, remove any infected leaves. Throw these leaves away. Don't put them in your compost pile. If you check your roses regularly and remove infected foliage immediately, you'll have a good chance of keeping black spot under control and keep it from infecting other parts of the plant.
Keep a clean garden. Pick up and throw away any fallen rose foliage regularly. Especially in late winter, rake up the area around your roses, dispose of any debris, and give the entire area a good three-inch deep layer of mulch. If you do this before new foliage begins to emerge, it's fairly unlikely that you'll have any major issues with black spot.
Choose resistant cultivars. If you've had persistent problems with black spot, be sure to make sure that any new roses you add to your garden are resistant. Your local cooperative extension service will be able to provide you with suggestions.
The old remedy of treating black spot with a baking soda spray has been shown to be ineffective. The only way to control black spot organically is to practice the prevention and maintenance tasks above.
Black spot is basically what it sounds like: roundish black spots on leaf surfaces. The spots grow over time, and the foliage around the spot yellows. Eventually, the entire leaf falls off.
Damage to Plants
The issue with black spot is that the defoliation that occurs when the fungus is allowed to get out of control weakens the plant. And not just for the current growing season, but for the next season as well.
The main function of plant foliage is to absorb energy from the sun and perform photosynthesis. If your plant loses all or most of its leaves to black spot, it will be unable to collect and store energy for the winter, as well as for the burst of growth that occurs in spring. You'll see weaker growth and reduced bloom in the season following severe black spot damage.
Disease Life Cycle
Black spot spores overwinter on infected foliage and canes, including infected foliage that has fallen and been left on the ground. In spring, spores are splashed up onto newly emerging foliage during rains or irrigation. Once the weather begins to stay consistently warm and humid, the spores germinate and infect the plant within one day. Visible symptoms (black spot and some yellowing) will be evident within five days, and it will produce and spread new spores within ten days. The new spores will infect other parts of the plant, or be carried on the wind to any other nearby rose bushes.
Treatment and Prevention
There are several organic ways to control black spot. Most of them rely on regular monitoring and upkeep. None of them are difficult and can be accomplished while you're admiring your roses.
Plant roses in full sun. If you give your roses a spot where they receive a full six to eight hours of sun per day, you'll not only have plants that grow more robustly, but also plants that are more able to resist black spot. Black spot loves moisture, and, in shade, water evaporates much more slowly. In full sun, evaporation happens more quickly, which not only helps prevent black spot, but other fungal diseases as well.
Plant roses in an area with good air circulation. This accomplishes the same thing as planting in an area with direct sunlight: moisture evaporates more quickly. In addition, with plenty of air circulation, hopefully breezes will blow any newly-germinated black spot spores away from your roses. In an area with poor air circulation, the spores have nowhere to go but back onto your plant and the surrounding soil.: moisture evaporates more quickly. In addition, with plenty of air circulation, hopefully breezes will blow any newly-germinated black spot spores away from your roses. In an area with poor air circulation, the spores have nowhere to go but back onto your plant and the surrounding soil.
Water correctly. Try to avoid overhead irrigation, which wets the foliage. It's more efficient to water at ground level anyway; you lose less water to evaporation. Also, avoid watering late in the day. Water evaporates much slower in cooler evening and nighttime temperatures.
Remove leaves that show signs of infection. As soon as you see black spot on your rose foliage, remove any infected leaves. Throw these leaves away. Don't put them in your compost pile. If you check your roses regularly and remove infected foliage immediately, you'll have a good chance of keeping black spot under control and keep it from infecting other parts of the plant.
Keep a clean garden. Pick up and throw away any fallen rose foliage regularly. Especially in late winter, rake up the area around your roses, dispose of any debris, and give the entire area a good three-inch deep layer of mulch. If you do this before new foliage begins to emerge, it's fairly unlikely that you'll have any major issues with black spot.
Choose resistant cultivars. If you've had persistent problems with black spot, be sure to make sure that any new roses you add to your garden are resistant. Your local cooperative extension service will be able to provide you with suggestions.
The old remedy of treating black spot with a baking soda spray has been shown to be ineffective. The only way to control black spot organically is to practice the prevention and maintenance tasks above.
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文章
Dummer. ゛☀
2017年09月13日
Symptoms of this fungal disease vary with the crop. Beans develop round, black, sunken spots on the pods and stems; on leaf undersides, veins turn black. When the fungus infects cucumbers and melons, the leaves develop yellow spots that dry up and flake away; spots on watermelon leaves are black. Infected fruits develop sunken areas with dark borders. On tomato plants, ripe fruit develops sunken spots with dark centers.
Anthracnose can also develop in other vegetable crops and in strawberries. Wind and wet weather fosters the spread of infection. Anthracnose overwinters in plant residues in the soil. It is an especially troublesome disease in hot, humid regions.
Prevention and Control
Plant resistant varieties such as Calypso cucumber and Charleston Gray watermelon.
Different species of fungi cause anthracnose in different crops. Thus, if you had anthracnose on your tomatoes last year, there’s no harm in planting beans in that bed this year. It can be helpful to wait two years before replanting tomatoes in that bed, though.
Use drip irrigation or soaker hoses rather than overhead watering. Avoid disturbing plant foliage when it’s wet.
Harvest tomato and pepper fruits promptly and wash and dry them immediately to remove any fungal spores on the fruit surface.
Clean up crop debris in fall.
Anthracnose can also develop in other vegetable crops and in strawberries. Wind and wet weather fosters the spread of infection. Anthracnose overwinters in plant residues in the soil. It is an especially troublesome disease in hot, humid regions.
Prevention and Control
Plant resistant varieties such as Calypso cucumber and Charleston Gray watermelon.
Different species of fungi cause anthracnose in different crops. Thus, if you had anthracnose on your tomatoes last year, there’s no harm in planting beans in that bed this year. It can be helpful to wait two years before replanting tomatoes in that bed, though.
Use drip irrigation or soaker hoses rather than overhead watering. Avoid disturbing plant foliage when it’s wet.
Harvest tomato and pepper fruits promptly and wash and dry them immediately to remove any fungal spores on the fruit surface.
Clean up crop debris in fall.
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Dummer. ゛☀
2017年09月13日
Northern corn leaf blight appears on corn leaves as distinct, grayish green to tan blotches or streaks up to 6″ long. Southern corn leaf blight causes smaller tan spots with reddish brown borders. Young corn plants are most susceptible to these fungal diseases, and if the infection is severe the plants may die.
Corn leaf blight is usually associated with commercial corn plantings. Wet, humid weather favors the spread of the disease and under these conditions corn leaf blight may also infect backyard corn plantings. The fungus overwinters on infected plant debris in the soil.
Prevention and Control
Plant blight-resistant varieties, such as Sugar Buns. Purchase only certified disease-free seed.
Rotate corn to avoid planting it in the same location more than once every three years.
Clean up the garden at the end of the growing season
Compost infected cornstalks in a hot compost pile (material must reach the disease-killing temperature of 150 degrees F for several days) or destroy them.
Corn leaf blight is usually associated with commercial corn plantings. Wet, humid weather favors the spread of the disease and under these conditions corn leaf blight may also infect backyard corn plantings. The fungus overwinters on infected plant debris in the soil.
Prevention and Control
Plant blight-resistant varieties, such as Sugar Buns. Purchase only certified disease-free seed.
Rotate corn to avoid planting it in the same location more than once every three years.
Clean up the garden at the end of the growing season
Compost infected cornstalks in a hot compost pile (material must reach the disease-killing temperature of 150 degrees F for several days) or destroy them.
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文章
Dummer. ゛☀
2017年09月13日
Water-soaked lesions between the veins of leaves are a telltale symptom of this bacterial disease, which infects cucumbers, summer squash, and melons. Symptoms often first appear on the underside of leaves. As infected areas in the leaf die, the tissue becomes brittle and those leaf parts fall away, giving afflicted leaves a ragged appearance. Angular leaf spot lesions may exude a milky fluid that dries on leaf surfaces. In severe outbreaks, lesions may also develop on stems and fruit.
The bacterium overwinters in the soil on seeds and plant residues, and is spread by rain splash and wind. Angular leaf spot is especially prevalent in warm, humid climates.
Prevention and Control
Plant vegetable varieties that are well-suited to your particular climate, and when possible, choose varieties such as Olympian cucumber that are resistant to angular leaf spot.
Practice a two- or three-year crop rotation of cucumbers and other squash-family crops to break the disease cycle.
Prevent the spread of disease by destroying infected plants and any that are in close proximity to them.
Splashing water spreads bacteria. Avoid overhead watering and use drip irrigation or soaker hoses to keep foliage as dry as possible. Avoid working in garden when plants are wet.
Avoid overfertilizing; excess nitrogen produces tender growth that is more vulnerable to infection
The bacterium overwinters in the soil on seeds and plant residues, and is spread by rain splash and wind. Angular leaf spot is especially prevalent in warm, humid climates.
Prevention and Control
Plant vegetable varieties that are well-suited to your particular climate, and when possible, choose varieties such as Olympian cucumber that are resistant to angular leaf spot.
Practice a two- or three-year crop rotation of cucumbers and other squash-family crops to break the disease cycle.
Prevent the spread of disease by destroying infected plants and any that are in close proximity to them.
Splashing water spreads bacteria. Avoid overhead watering and use drip irrigation or soaker hoses to keep foliage as dry as possible. Avoid working in garden when plants are wet.
Avoid overfertilizing; excess nitrogen produces tender growth that is more vulnerable to infection
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文章
Dummer. ゛☀
2017年09月03日
Trees growing in the wild rely on the soil to provide the nutrients they need to grow. In a backyard environment, trees and shrubs compete for available nutrients and may require fertilizer to keep them healthy. Arborvitae are narrow-leaf evergreen trees with leaves that look like scales. Different arborvitae species grow into different shapes and sizes, making the tree an excellent choice for hedges of any height or specimen plants. Beloved for their fast growth, arborvitae – especially those planted near other trees or in hedges – often require fertilizer to thrive. It isn’t difficult to begin fertilizing arborvitae. Read on to learn how to fertilize an arborvitae and the type of fertilizer for arborvitae.
Fertilizing Arborvitae
Many mature trees do not require fertilizing. If your arborvitae is planted alone as a specimen tree and appears happy and thriving, consider skipping the fertilizer for the present time. If your trees are fighting for nutrients with other plants, they may need fertilizer. Check to see if they are growing slowly or otherwise look unhealthy. Before you fertilize, learn about the optimal type of fertilizer for these tough evergreens.
What Type of Fertilizer for Arborvitae?
If you want to start providing fertilizer for arborvitae trees, you need to select a fertilizer. You can select a single-nutrient fertilizer like nitrogen, but unless you are completely certain that your soil is rich in all other nutrients, it may be better to opt for a complete fertilizer for trees. Experts recommend slow release granular fertilizer for arborvitae trees. The nitrogen in this fertilizer is released over a long period of time. This enables you to fertilize less often and also ensures that the tree’s roots will not burn. Select a slow-release fertilizer that includes at least 50 percent nitrogen.
How to Fertilize an Arborvitae?
Applying fertilizer for arborvitae trees correctly is a matter of following easy directions. The fertilizer container will tell you how much of the product to use per tree. To fertilize your trees, broadcast the recommended amount of fertilizer evenly over the root zone. Keep the granules well away from the plant’s trunk area. Water the soil beneath the tree well when you are done fertilizing arborvitae. This helps the fertilizer dissolve so that it is accessible to the roots.
When to Feed Arborvitae?
It is also important to know when to feed arborvitae. Fertilizing arborvitae at the wrong time can lead to problems with the tree. You should fertilize your arborvitae during the growing season. Offer the first feeding just before new growth begins. Fertilize at the intervals recommended on the container. Stop fertilizing arborvitae one month before the first frost in your region.
Fertilizing Arborvitae
Many mature trees do not require fertilizing. If your arborvitae is planted alone as a specimen tree and appears happy and thriving, consider skipping the fertilizer for the present time. If your trees are fighting for nutrients with other plants, they may need fertilizer. Check to see if they are growing slowly or otherwise look unhealthy. Before you fertilize, learn about the optimal type of fertilizer for these tough evergreens.
What Type of Fertilizer for Arborvitae?
If you want to start providing fertilizer for arborvitae trees, you need to select a fertilizer. You can select a single-nutrient fertilizer like nitrogen, but unless you are completely certain that your soil is rich in all other nutrients, it may be better to opt for a complete fertilizer for trees. Experts recommend slow release granular fertilizer for arborvitae trees. The nitrogen in this fertilizer is released over a long period of time. This enables you to fertilize less often and also ensures that the tree’s roots will not burn. Select a slow-release fertilizer that includes at least 50 percent nitrogen.
How to Fertilize an Arborvitae?
Applying fertilizer for arborvitae trees correctly is a matter of following easy directions. The fertilizer container will tell you how much of the product to use per tree. To fertilize your trees, broadcast the recommended amount of fertilizer evenly over the root zone. Keep the granules well away from the plant’s trunk area. Water the soil beneath the tree well when you are done fertilizing arborvitae. This helps the fertilizer dissolve so that it is accessible to the roots.
When to Feed Arborvitae?
It is also important to know when to feed arborvitae. Fertilizing arborvitae at the wrong time can lead to problems with the tree. You should fertilize your arborvitae during the growing season. Offer the first feeding just before new growth begins. Fertilize at the intervals recommended on the container. Stop fertilizing arborvitae one month before the first frost in your region.
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Dummer. ゛☀
2017年09月02日
Plum leaf sand cherry, also referred to as purple leaf sand cherry plants, is a medium sized ornamental shrub or small tree that when mature reaches a height of approximately 8 feet tall by 8 feet wide. This easy care plant makes a great addition to the landscape.
About Plum Leaf Sand Cherry
Purple leaf sand cherry (Prunus x cistena) is a member of the Rose family. Prunus is Latin for ‘plum’ while cistena is the Sioux word for ‘baby’ in reference to its smallish size. The “x” is indicative of the shrub’s hybridism.
This Prunus hybrid is useful as an ornamental specimen due to its beautiful red, maroon, or purple foliage. The shrub grows at a moderate rate and is suitable in USDA zones 2-8. The parent plants of sandcherry bush hail from Western Asia (Prunus cerasifera) and the Northeastern United States (Prunus pumila).
This purplish-red leafed plant has an oval growth habit gradually maturing into an arched form and opening out from the center of the shrub. The stunning 2-inch long, serrated foliage emerges crimson-purple and remains throughout the summer, gradually changing to a green-bronze hue in the fall. Around early spring, the plant’s pink buds open into whitish-pink flowers – the same time as the red foliage. The innocuous blooms become small black-purple fruit barely noticeable without contrast to the purple foliage in July. The multiple gray-brown trunks are prone to trunk fissuring and cankers, which ooze sap.
How to Grow a Purple Leaf Sand Cherry
This specimen is urban tolerant and establishes rapidly to lend a brilliant pop of color to the landscape. So how do you grow a purple leaf sand cherry? Sand cherry is readily available through the local nursery and/or propagated via rooted stem cuttings. Sand cherry is sensitive to being transplanted in the autumn, so extra care should be taken in amending the soil, fertilizing, mulching heavily and watering thoroughly. Ideally, you should plant the purple leaf sand cherry in full to partial sun exposure in moist, well-draining soil. However, the sand cherry bush is adaptable to lesser soils, drought, heat and over aggressive pruning.
Sand Cherry Plant Care
Because, the sand cherry is a member of the Rose family, it is susceptible to several diseases, such as trunk canker, and pests, like borers and Japanese beetle assaults in mid-summer. It also has a short lifespan at between 10 to 15 years primarily due to assault by pests or diseases. Other than these issues, the sand cherry plant care is relatively fuss free and is tolerant of a variety of conditions – hardy in cold winters and hot summers. Prune the sand cherry bush to remove heavy branching that will weigh the plant down. It can even be pruned into a formal hedge or used in borders, at entranceways or in group plantings.
About Plum Leaf Sand Cherry
Purple leaf sand cherry (Prunus x cistena) is a member of the Rose family. Prunus is Latin for ‘plum’ while cistena is the Sioux word for ‘baby’ in reference to its smallish size. The “x” is indicative of the shrub’s hybridism.
This Prunus hybrid is useful as an ornamental specimen due to its beautiful red, maroon, or purple foliage. The shrub grows at a moderate rate and is suitable in USDA zones 2-8. The parent plants of sandcherry bush hail from Western Asia (Prunus cerasifera) and the Northeastern United States (Prunus pumila).
This purplish-red leafed plant has an oval growth habit gradually maturing into an arched form and opening out from the center of the shrub. The stunning 2-inch long, serrated foliage emerges crimson-purple and remains throughout the summer, gradually changing to a green-bronze hue in the fall. Around early spring, the plant’s pink buds open into whitish-pink flowers – the same time as the red foliage. The innocuous blooms become small black-purple fruit barely noticeable without contrast to the purple foliage in July. The multiple gray-brown trunks are prone to trunk fissuring and cankers, which ooze sap.
How to Grow a Purple Leaf Sand Cherry
This specimen is urban tolerant and establishes rapidly to lend a brilliant pop of color to the landscape. So how do you grow a purple leaf sand cherry? Sand cherry is readily available through the local nursery and/or propagated via rooted stem cuttings. Sand cherry is sensitive to being transplanted in the autumn, so extra care should be taken in amending the soil, fertilizing, mulching heavily and watering thoroughly. Ideally, you should plant the purple leaf sand cherry in full to partial sun exposure in moist, well-draining soil. However, the sand cherry bush is adaptable to lesser soils, drought, heat and over aggressive pruning.
Sand Cherry Plant Care
Because, the sand cherry is a member of the Rose family, it is susceptible to several diseases, such as trunk canker, and pests, like borers and Japanese beetle assaults in mid-summer. It also has a short lifespan at between 10 to 15 years primarily due to assault by pests or diseases. Other than these issues, the sand cherry plant care is relatively fuss free and is tolerant of a variety of conditions – hardy in cold winters and hot summers. Prune the sand cherry bush to remove heavy branching that will weigh the plant down. It can even be pruned into a formal hedge or used in borders, at entranceways or in group plantings.
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