文章
Dummer. ゛☀
2017年09月14日
I've gotten a few questions over the past week or two from readers who have noticed white, fuzzy mold growing on their seedlings. This is a fairly common issue for those who start their own plants from seeds. Most of us plant our seeds and take care to keep the seedlings moist, but that can cause the white fuzzy mold to appear on them.
There is good news for your seedlings--and your garden, too. The fungus itself is not going to hurt your seedlings.
The bad news: that fungus is a sign that your soil is too wet. Soil that is too wet can result in having the delicate roots of your seedlings rot, which will eventually result in plant death.
How to Stop White Fuzzy Mold on Seedlings
Luckily, the mold is an easy thing to fix. Chances are, you are causing the mold by watering too much. Don't water your plants-to-be unless the seedlings really need it. It is easy to get into a routine of just giving them a quick water every day or so "just to be sure," but this can sometimes do more harm than good. Check the soil's moisture with your finger; only water if the soil is dry. That simple check can help you stop the white fuzzy mold from growing.
Rethink how much you water when you do water. You may simply need to cut down the amount of water you put on each seedling--another way to reduce white fuzzy mold for healthier seedlings.
Another thing that can help kill off the mold and prevent it from growing is to increase the air flow around your seedlings.
You can do this by having a fan running nearby for at least a few hours a day. Not only does this help prohibit fungal growth, but it also results in sturdier seedlings.
Additionally, you may want to look at how much light the seedlings are getting. They need at least twelve hours of good, strong light per day to grow well.
That also helps the water to dissipate and not sit stagnant. Try not to place them in direct sunlight, either, because covered trays can get too hot and damage the seedlings. Check the temperature, too. The best photosynthesis occurs when the temperature stays between 77°F and 82°F).
Finally, if at all possible, consider a system that lets you water from the bottom of the seedling container. This not only encourages the roots to grow deeper. It also helps alleviate mold and fungus because the surface of the soil is not constantly moist, so it cannot grow.
Once you do one or all of those things, you can actually remove the white mold from your seedlings. Gently scrape it away with a knife or spoon.
There is good news for your seedlings--and your garden, too. The fungus itself is not going to hurt your seedlings.
The bad news: that fungus is a sign that your soil is too wet. Soil that is too wet can result in having the delicate roots of your seedlings rot, which will eventually result in plant death.
How to Stop White Fuzzy Mold on Seedlings
Luckily, the mold is an easy thing to fix. Chances are, you are causing the mold by watering too much. Don't water your plants-to-be unless the seedlings really need it. It is easy to get into a routine of just giving them a quick water every day or so "just to be sure," but this can sometimes do more harm than good. Check the soil's moisture with your finger; only water if the soil is dry. That simple check can help you stop the white fuzzy mold from growing.
Rethink how much you water when you do water. You may simply need to cut down the amount of water you put on each seedling--another way to reduce white fuzzy mold for healthier seedlings.
Another thing that can help kill off the mold and prevent it from growing is to increase the air flow around your seedlings.
You can do this by having a fan running nearby for at least a few hours a day. Not only does this help prohibit fungal growth, but it also results in sturdier seedlings.
Additionally, you may want to look at how much light the seedlings are getting. They need at least twelve hours of good, strong light per day to grow well.
That also helps the water to dissipate and not sit stagnant. Try not to place them in direct sunlight, either, because covered trays can get too hot and damage the seedlings. Check the temperature, too. The best photosynthesis occurs when the temperature stays between 77°F and 82°F).
Finally, if at all possible, consider a system that lets you water from the bottom of the seedling container. This not only encourages the roots to grow deeper. It also helps alleviate mold and fungus because the surface of the soil is not constantly moist, so it cannot grow.
Once you do one or all of those things, you can actually remove the white mold from your seedlings. Gently scrape it away with a knife or spoon.
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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
Fusarium wilt (foo-zair-ee-um) is caused by the fungus Fusarium oxysporum f.sp. lycopersici. Fusarium wilt is found worldwide and even resistant tomato varieties may be affected. The fungus is soil borne and makes its way into the plant through the roots. Once inside, it clogs and blocks the xylem, the tissue that moves water and some nutrients through the plant, preventing water from traveling up the stem and out into the branches and leaves.
It may not kill your tomato plants, but they won't be very productive.
Species of Fusarium can infect many plants including: potatoes, peppers, eggplants, legumes and bananas.
Symptoms of Verticillium wilt can be very similar to Fusarium wilt.
What Causes Fusarium Wilt?
The Fusarium wilt pathogen is soil borne and can remain in infected soil for years. It can also be carried and transmitted in multiple ways, like:
infected seed
seedlings from infected soil
the bottom of shoes
shovels and equipment used in infected soil
infected soil blown into the garden
Ideal conditions for Fusarium wilt include warm, dry weather and acidic soil pH (5.0 - 5.6)
There are tomato varieties that are resistant to fusarium wilt, but if they are weakened by root-knot nematode, they become more susceptible to it.
Plants infected with Fusarium wilt will be stunted and the earlier they are infected, them more severe the stunting.
Keep reading for more photos and descriptions of Fusarium Wilt symptoms and how to control it.
Symptoms of Fusarium Wilt on Tomatoes
Fusarium wilt can sometimes be confused with other wilts, but here are some symptoms to help you identify it in tomatoes:
Wilting The plants will literally wilt. Often it starts with a single leaf or shoot, near the top of the plant. It will recover at night, when temperatures are cooler, but as it progresses, the entire plant will wilt and not recover. Watering does not make a difference.
Yellowing Lower leaves will turn yellow, often starting on only one side. As with the wilting, the yellowing will gradually move up the plant.
Dry Leaves The wilted leaves will dry out and fall off.
Discolored Stem If you cut open the stem length-wise you will see dark brown streaks.
Management and Control of Fusarium Wilt of Tomatoes
There is no cure for Fusarium and since it persists in the soil for years, it can be very hard to eradicate. Here are some measures to help you control it.
Resistant Varieties - If you've had problems with Fusarium wilt, you would be wise to stick with resistant varieties. Seed packets and many seedlings will be labeled with their resistance to various diseases. You could also consult a seed catalog for choices.
Sterile Potting Soil - If you are starting your own seedlings, begin with a sterile soilless potting mix.
Raise the Soil pH - Apply lime to the soil in your garden, to bring the pH up into the neutral range of about 6.5 - 7.0.
Control Nematodes - Since root-knot nematodes can lessen resistance to Fusarium wilt, don't let nematode populations build up in your soil.
Don't Cultivate - Avoid injuring plants' roots by not using a hoe or cultivator around your tomato plants. Damaged roots are entry points for the pathogen.
Disinfect Tools - Clean all tools that may have come in contact with infected soil and make it a habit to regularly clean and disinfect your garden tools.
Rotate Your Crops - Since the pathogen can persist in the soil for years, you will have to find another area to plant your tomatoes. A 5 to 7 year rotation is recommended, but that does not guarantee the pathogen will be entirely gone.
It may not kill your tomato plants, but they won't be very productive.
Species of Fusarium can infect many plants including: potatoes, peppers, eggplants, legumes and bananas.
Symptoms of Verticillium wilt can be very similar to Fusarium wilt.
What Causes Fusarium Wilt?
The Fusarium wilt pathogen is soil borne and can remain in infected soil for years. It can also be carried and transmitted in multiple ways, like:
infected seed
seedlings from infected soil
the bottom of shoes
shovels and equipment used in infected soil
infected soil blown into the garden
Ideal conditions for Fusarium wilt include warm, dry weather and acidic soil pH (5.0 - 5.6)
There are tomato varieties that are resistant to fusarium wilt, but if they are weakened by root-knot nematode, they become more susceptible to it.
Plants infected with Fusarium wilt will be stunted and the earlier they are infected, them more severe the stunting.
Keep reading for more photos and descriptions of Fusarium Wilt symptoms and how to control it.
Symptoms of Fusarium Wilt on Tomatoes
Fusarium wilt can sometimes be confused with other wilts, but here are some symptoms to help you identify it in tomatoes:
Wilting The plants will literally wilt. Often it starts with a single leaf or shoot, near the top of the plant. It will recover at night, when temperatures are cooler, but as it progresses, the entire plant will wilt and not recover. Watering does not make a difference.
Yellowing Lower leaves will turn yellow, often starting on only one side. As with the wilting, the yellowing will gradually move up the plant.
Dry Leaves The wilted leaves will dry out and fall off.
Discolored Stem If you cut open the stem length-wise you will see dark brown streaks.
Management and Control of Fusarium Wilt of Tomatoes
There is no cure for Fusarium and since it persists in the soil for years, it can be very hard to eradicate. Here are some measures to help you control it.
Resistant Varieties - If you've had problems with Fusarium wilt, you would be wise to stick with resistant varieties. Seed packets and many seedlings will be labeled with their resistance to various diseases. You could also consult a seed catalog for choices.
Sterile Potting Soil - If you are starting your own seedlings, begin with a sterile soilless potting mix.
Raise the Soil pH - Apply lime to the soil in your garden, to bring the pH up into the neutral range of about 6.5 - 7.0.
Control Nematodes - Since root-knot nematodes can lessen resistance to Fusarium wilt, don't let nematode populations build up in your soil.
Don't Cultivate - Avoid injuring plants' roots by not using a hoe or cultivator around your tomato plants. Damaged roots are entry points for the pathogen.
Disinfect Tools - Clean all tools that may have come in contact with infected soil and make it a habit to regularly clean and disinfect your garden tools.
Rotate Your Crops - Since the pathogen can persist in the soil for years, you will have to find another area to plant your tomatoes. A 5 to 7 year rotation is recommended, but that does not guarantee the pathogen will be entirely gone.
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文章
Dummer. ゛☀
2017年09月13日
Emerald cedar (more properly termed "arborvitae") is a highly useful tall shrub or small tree, but homeowners and businesses who plant it frequently experience the problem of having its leaves turn brown. Insects, diseases, or even dog urine can be the sources of the problem if the leaves are turning brown in summer, as well as a more obvious potential culprit: namely, drought.
Many people have asked me to address this issue.
Arborvitae is widely planted in highly visible hedges and foundation plantings, where brown leaves will stick out like a sore thumb and create an eyesore. I was finally inspired to write an article about the problem by a reader who emailed me the following question:
I planted over 40 Emerald Cedars along the border between my property and my neighbour as a privacy fence, as well as a sound barrier for my dogs barking. I planted the trees at least 5 years ago, and just last summer I noticed that they are all turning brown, instead of having that lovely fresh green colour they used to. Can you tell me what the problem is and what you might suggest as a remedy to save my Emerald cedar trees?
Location of Brown Foliage Determines Whether You Have a True Problem
When you see brown leaves on the inner part of Emerald cedars, that is generally not a problem: it is normal to see brown leaves in this area in fall or spring, as that foliage is just getting old and the Emerald cedars are shedding it.
But leaves turning brown at the outer tips of branches can be a serious problem. If you see such brown leaves in the summer, it could be due to any of the following (or some combination thereof):
Your Emerald cedars could be infested with aphids (in which case you would have to spray). Inspect foliage closely for masses of these tiny, soft-bodied insects.
They could be infested with spider mites (in which case you would have to spray). Look closely for tiny webs.
Your Emerald cedars could be succumbing to fungal diseases. Look for tiny black spots in summer. If you see them, remove infected branches to prevent further spread. If the problem persists, have your local garden center recommend an antifungal spray.
During a hot, dry summer, plants often fail to receive sufficient water.
To address reason #4 above, as a preventive measure, you can supply artificial irrigation and bark mulch. For established plants, a deep soaking every other week is sometimes recommended. Of course, this does not address the issue of vegetation that has already been damaged by drought. In severe cases, root damage can occur, resulting in dead plants. How do you check to see if your plant is dead or still alive? Slice off a bit of bark with a knife, so that you can "look under the hood," so to speak. If you see green, the plant is probably still alive (on a partially dead plant, it may take you a few tries before you find green somewhere). If all that you find is brown, the plant is most likely dead, and you should start making plans to remove it and replace it.
Is Your Yard Going to the Dogs?
Although this does not apply to the reader mentioned above (because it is unlikely to account for browning on 40 Emerald cedar trees all at once), it could apply to someone with a small number of Emerald cedars: if the foliage has been sprayed with dog urine, that can cause brown leaves. This is just one of many examples of the challenges we face in landscaping with dogs. If there is a stray dog problem in your area, you can deter dogs with dog repellents.
Note also that, in diagnosing and solving this problem of Emerald cedar leaves turning brown, it is important to specify the time of year. The above assumes the problem developed during the summer. I have a separate FAQ dealing with brown leaves on arborvitae (Emerald cedars) in winter.
Many people have asked me to address this issue.
Arborvitae is widely planted in highly visible hedges and foundation plantings, where brown leaves will stick out like a sore thumb and create an eyesore. I was finally inspired to write an article about the problem by a reader who emailed me the following question:
I planted over 40 Emerald Cedars along the border between my property and my neighbour as a privacy fence, as well as a sound barrier for my dogs barking. I planted the trees at least 5 years ago, and just last summer I noticed that they are all turning brown, instead of having that lovely fresh green colour they used to. Can you tell me what the problem is and what you might suggest as a remedy to save my Emerald cedar trees?
Location of Brown Foliage Determines Whether You Have a True Problem
When you see brown leaves on the inner part of Emerald cedars, that is generally not a problem: it is normal to see brown leaves in this area in fall or spring, as that foliage is just getting old and the Emerald cedars are shedding it.
But leaves turning brown at the outer tips of branches can be a serious problem. If you see such brown leaves in the summer, it could be due to any of the following (or some combination thereof):
Your Emerald cedars could be infested with aphids (in which case you would have to spray). Inspect foliage closely for masses of these tiny, soft-bodied insects.
They could be infested with spider mites (in which case you would have to spray). Look closely for tiny webs.
Your Emerald cedars could be succumbing to fungal diseases. Look for tiny black spots in summer. If you see them, remove infected branches to prevent further spread. If the problem persists, have your local garden center recommend an antifungal spray.
During a hot, dry summer, plants often fail to receive sufficient water.
To address reason #4 above, as a preventive measure, you can supply artificial irrigation and bark mulch. For established plants, a deep soaking every other week is sometimes recommended. Of course, this does not address the issue of vegetation that has already been damaged by drought. In severe cases, root damage can occur, resulting in dead plants. How do you check to see if your plant is dead or still alive? Slice off a bit of bark with a knife, so that you can "look under the hood," so to speak. If you see green, the plant is probably still alive (on a partially dead plant, it may take you a few tries before you find green somewhere). If all that you find is brown, the plant is most likely dead, and you should start making plans to remove it and replace it.
Is Your Yard Going to the Dogs?
Although this does not apply to the reader mentioned above (because it is unlikely to account for browning on 40 Emerald cedar trees all at once), it could apply to someone with a small number of Emerald cedars: if the foliage has been sprayed with dog urine, that can cause brown leaves. This is just one of many examples of the challenges we face in landscaping with dogs. If there is a stray dog problem in your area, you can deter dogs with dog repellents.
Note also that, in diagnosing and solving this problem of Emerald cedar leaves turning brown, it is important to specify the time of year. The above assumes the problem developed during the summer. I have a separate FAQ dealing with brown leaves on arborvitae (Emerald cedars) in winter.
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文章
Dummer. ゛☀
2017年09月13日
What is Powdery Mildew?
Powdery mildew is one of the most commonly occurring plants problems. It is a fungal disease that affects plant leaves and stems, coating them in what looks like a white or gray powder-like substance. Although any plant can get powdery mildew, some are very susceptible, crab apples, cucumbers and all types of squash, lilacs, phlox and roses. In severe cases, powdery mildew can even spread to the buds, flowers, and fruits of plants.
The white coating greatly diminishes the appearance of the plant, but it is not fatal unless left uncontrolled. However, as it spreads, it stresses and weakens the plant and makes it hard for photosynthesis to occur. It's wise to treat it as soon as you see symptoms, or maybe even before.
Controlling Powdery Mildew with Baking Soda
Baking soda has long been used as an inexpensive control for powdery mildew on plants. Unfortunately baking soda fungicide is mostly effective as a preventative, offering only minimal benefits after your plants have become infected. If you know which plants are susceptible, spraying them weekly with the baking soda recipes, during humid or damp weather, can greatly reduce the incidence of powdery mildew in your garden.
To control powdery mildew on plants, mix together:
1 tablespoon of baking soda
½ teaspoon of liquid soap
1 gallon of water
Do not store unused mixture.
While this recipe has been known to be effective, it can burn the leaves of some plants. It is recommended that you water your infected plants well a couple of days before applying this mixture, and don’t apply it in full sun. Try on a small area first, to test the plant’s response before spraying the entire plant.
Some recipes also recommend applying 1 tablespoon of ultralight horticultural oil to the mixture. The oil coats and smothers the fungi. The soap is added to help the mix spread and cling to the leaf surface. Be sure to apply to lower leaf surfaces as well.
Control versus Cure
Unfortunately, this baking soda mixture works best as a preventative, applied before powdery mildew has a chance to spread on your plant. It is less effective as a cure, once the fungus has taken hold. If you know a plant is affected by powdery mildew year after year, as is the case with many monarda, pholx, and lilacs, they spraying early in the season may prevent any occurrence of powdery mildew that year. It is still worth trying after signs of powdery mildew appear, but it might not get rid of all the fungus.
Another Homemade Powdery Mildew Option
Spraying plants with a milk mixture, after they have been infected with powdery mildew, is showing a lot of promise for actually killing the fungus. Read more about how to use milk to control powdery mildew.
There May be More Uses for This Baking Soda Recipe
Researchers are still studying the effects of using a baking soda mixture on other fungal diseases such as: black spot, rust and anthracnose.
Powdery mildew is one of the most commonly occurring plants problems. It is a fungal disease that affects plant leaves and stems, coating them in what looks like a white or gray powder-like substance. Although any plant can get powdery mildew, some are very susceptible, crab apples, cucumbers and all types of squash, lilacs, phlox and roses. In severe cases, powdery mildew can even spread to the buds, flowers, and fruits of plants.
The white coating greatly diminishes the appearance of the plant, but it is not fatal unless left uncontrolled. However, as it spreads, it stresses and weakens the plant and makes it hard for photosynthesis to occur. It's wise to treat it as soon as you see symptoms, or maybe even before.
Controlling Powdery Mildew with Baking Soda
Baking soda has long been used as an inexpensive control for powdery mildew on plants. Unfortunately baking soda fungicide is mostly effective as a preventative, offering only minimal benefits after your plants have become infected. If you know which plants are susceptible, spraying them weekly with the baking soda recipes, during humid or damp weather, can greatly reduce the incidence of powdery mildew in your garden.
To control powdery mildew on plants, mix together:
1 tablespoon of baking soda
½ teaspoon of liquid soap
1 gallon of water
Do not store unused mixture.
While this recipe has been known to be effective, it can burn the leaves of some plants. It is recommended that you water your infected plants well a couple of days before applying this mixture, and don’t apply it in full sun. Try on a small area first, to test the plant’s response before spraying the entire plant.
Some recipes also recommend applying 1 tablespoon of ultralight horticultural oil to the mixture. The oil coats and smothers the fungi. The soap is added to help the mix spread and cling to the leaf surface. Be sure to apply to lower leaf surfaces as well.
Control versus Cure
Unfortunately, this baking soda mixture works best as a preventative, applied before powdery mildew has a chance to spread on your plant. It is less effective as a cure, once the fungus has taken hold. If you know a plant is affected by powdery mildew year after year, as is the case with many monarda, pholx, and lilacs, they spraying early in the season may prevent any occurrence of powdery mildew that year. It is still worth trying after signs of powdery mildew appear, but it might not get rid of all the fungus.
Another Homemade Powdery Mildew Option
Spraying plants with a milk mixture, after they have been infected with powdery mildew, is showing a lot of promise for actually killing the fungus. Read more about how to use milk to control powdery mildew.
There May be More Uses for This Baking Soda Recipe
Researchers are still studying the effects of using a baking soda mixture on other fungal diseases such as: black spot, rust and anthracnose.
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文章
Dummer. ゛☀
2017年09月13日
What is Black Spot?
Black spot is a fungal disease (Diplocarpon rosae), that affects roses. It causes black spots on leaves, eventually causing the leaves to turn yellow and drop off. Besides looking unsightly, it can seriously weaken the rose plant. Ideal conditions include hot, humid or rainy summers and hot days with cool, damp nights.
Symptoms:
Somewhat circular black spots on leaves. They usually occur on the upper sides of leaves, but can also develop on the undersides.
The outer margins of the black circles are ragged or feathery and they are usually surrounded by a ring of yellow.
Spots begin on the lower foliage and move upward. They can appear as early as when the leaves first unfurl. These spots can enlarge and merge. Severally affected leaves often fall off the plants and left unchecked, the entire plant can defoliate.
The fungus can also infect young canes, causing dark purple or black blisters, and even the flowers may show some red spotting. Infected plants will set fewer flower buds and without leaves, the plant becomes stressed and is susceptible to even more problems.
Cultural Controls
Growing Conditions - Make the growing conditions less hospitable for black spot. Black spot is easier to prevent than to cure. The spores can remain in the soil and overwinter on leaves and stems, waiting for favorable conditions. They make contact with the rose by splashing up in drops of water.
Give the plant what it wants. This is true for avoiding any plant disease. A healthy, vigorous plant is less susceptible to problems. Roses prefer a sunny location with well-draining soil and regular weekly watering.
Air Flow - Provide good air circulation around and through your rose plants. Don't plant your roses too close to other plants. Prune to open the spaces between canes, if the plant gets too dense and air can not get through.
Proper Watering - Avoid getting the leaves wet, while watering. There's not much you can do about rain, but at least limit the time the leaves remain wet.
Plant resistant cultivars - Roses are often labeled for resistance, from highly resistant on down. While you are looking for black spot resistance, you might as well look for a rose that is also resistant to rust and powdery mildew. Rugosas, the newer shrub and ground cover roses and many of the Canadian Explorer Series, like John Cabot and William Baffin, show good resistance.
Sanitation - Remove any infected leaves and always do a thorough cleanup each fall. Remove and dispose of any remaining leaves, when you do your dormant pruning in late winter/early spring. Spores can remain on leaves and stems throughout and will reinfect whenever conditions are favorable. Within 10 days of the first symptoms, the disease has already started spreading. Spores can spread by water and wind.
Prune out any canes showing signs of infection. Prune 6 – 8 inches below the infection and only prune in dry weather. Disinfect your pruners with a 10% bleach solution or alcohol, between cuts.
Mulch - Apply a thick layer of mulch around the plants. Mulch will prevent water from splashing up on the plant and spreading spores.
Sprays for Treatment and Prevention
It is easier to prevent black spot than to cure it, but it is time-consuming.
If black spot is a reoccurring problem in your area, you may need to spray your plants weekly, starting in early spring.
Baking soda spray - Dissolve 1 teaspoon baking soda in 1-quart warm water. Add up to 1 teaspoon liquid soap. Spray leaves thoroughly. This mixture works better as a preventive than as a cure. Also offers some protection from powdery mildew.
Bordeaux Mix - This is a fungicide that contains copper sulfate and hydrated lime. It can be used as a powder or mixed with water and sprayed. Bordeaux mix also repels some insect pests, but it can burn plant leaves. It is generally used as a preventative in the spring, before plants leaf out.
Insecticidal soaps with added fungicide - These are basically some type of organic fungicide, often sulfur, added to regular insecticidal soap. The soap helps the fungicide adhere to the plant leaves and spread to coat them.
Neem Oil - Neem is an organic fungicide and pesticide, derived from the seeds of the neem tree. It gets inside the plant's system, so you don't need to worry about coating everything or reapplying after a rain. However, it can burn plant leaves in hot sun. You should not apply need oil within 2 weeks of using a product containing sulfur.
Sulfur - Sulfur both prevents and gets rid of fungus diseases. It is also used to control several insect pests. However it can be mildly toxic to humans and other animals. You should wear protective clothing when you spray it. It can also corrode metal, so use a plastic sprayer . And it can burn plants leaves in hot weather.
Sulfur comes as a finely ground powder. If you prefer to spray it on, look for one labeled as wettable, so that it will mix with water.
Black spot is a fungal disease (Diplocarpon rosae), that affects roses. It causes black spots on leaves, eventually causing the leaves to turn yellow and drop off. Besides looking unsightly, it can seriously weaken the rose plant. Ideal conditions include hot, humid or rainy summers and hot days with cool, damp nights.
Symptoms:
Somewhat circular black spots on leaves. They usually occur on the upper sides of leaves, but can also develop on the undersides.
The outer margins of the black circles are ragged or feathery and they are usually surrounded by a ring of yellow.
Spots begin on the lower foliage and move upward. They can appear as early as when the leaves first unfurl. These spots can enlarge and merge. Severally affected leaves often fall off the plants and left unchecked, the entire plant can defoliate.
The fungus can also infect young canes, causing dark purple or black blisters, and even the flowers may show some red spotting. Infected plants will set fewer flower buds and without leaves, the plant becomes stressed and is susceptible to even more problems.
Cultural Controls
Growing Conditions - Make the growing conditions less hospitable for black spot. Black spot is easier to prevent than to cure. The spores can remain in the soil and overwinter on leaves and stems, waiting for favorable conditions. They make contact with the rose by splashing up in drops of water.
Give the plant what it wants. This is true for avoiding any plant disease. A healthy, vigorous plant is less susceptible to problems. Roses prefer a sunny location with well-draining soil and regular weekly watering.
Air Flow - Provide good air circulation around and through your rose plants. Don't plant your roses too close to other plants. Prune to open the spaces between canes, if the plant gets too dense and air can not get through.
Proper Watering - Avoid getting the leaves wet, while watering. There's not much you can do about rain, but at least limit the time the leaves remain wet.
Plant resistant cultivars - Roses are often labeled for resistance, from highly resistant on down. While you are looking for black spot resistance, you might as well look for a rose that is also resistant to rust and powdery mildew. Rugosas, the newer shrub and ground cover roses and many of the Canadian Explorer Series, like John Cabot and William Baffin, show good resistance.
Sanitation - Remove any infected leaves and always do a thorough cleanup each fall. Remove and dispose of any remaining leaves, when you do your dormant pruning in late winter/early spring. Spores can remain on leaves and stems throughout and will reinfect whenever conditions are favorable. Within 10 days of the first symptoms, the disease has already started spreading. Spores can spread by water and wind.
Prune out any canes showing signs of infection. Prune 6 – 8 inches below the infection and only prune in dry weather. Disinfect your pruners with a 10% bleach solution or alcohol, between cuts.
Mulch - Apply a thick layer of mulch around the plants. Mulch will prevent water from splashing up on the plant and spreading spores.
Sprays for Treatment and Prevention
It is easier to prevent black spot than to cure it, but it is time-consuming.
If black spot is a reoccurring problem in your area, you may need to spray your plants weekly, starting in early spring.
Baking soda spray - Dissolve 1 teaspoon baking soda in 1-quart warm water. Add up to 1 teaspoon liquid soap. Spray leaves thoroughly. This mixture works better as a preventive than as a cure. Also offers some protection from powdery mildew.
Bordeaux Mix - This is a fungicide that contains copper sulfate and hydrated lime. It can be used as a powder or mixed with water and sprayed. Bordeaux mix also repels some insect pests, but it can burn plant leaves. It is generally used as a preventative in the spring, before plants leaf out.
Insecticidal soaps with added fungicide - These are basically some type of organic fungicide, often sulfur, added to regular insecticidal soap. The soap helps the fungicide adhere to the plant leaves and spread to coat them.
Neem Oil - Neem is an organic fungicide and pesticide, derived from the seeds of the neem tree. It gets inside the plant's system, so you don't need to worry about coating everything or reapplying after a rain. However, it can burn plant leaves in hot sun. You should not apply need oil within 2 weeks of using a product containing sulfur.
Sulfur - Sulfur both prevents and gets rid of fungus diseases. It is also used to control several insect pests. However it can be mildly toxic to humans and other animals. You should wear protective clothing when you spray it. It can also corrode metal, so use a plastic sprayer . And it can burn plants leaves in hot weather.
Sulfur comes as a finely ground powder. If you prefer to spray it on, look for one labeled as wettable, so that it will mix with water.
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成长记
Dunia Carrillo
2017年09月13日
Update the growth of this plant in just 2 days that it was in a dark room. Just incredibly exciting!
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文章
Dummer. ゛☀
2017年09月13日
Description
Garden aphids, also known as plant lice, include many different species in the Aphidoidea insect family. Aphids are very small--roughly 1/10th of an inch long. The most common colors are green and black, though brown, reddish-brown, and gray aphids inhabit some parts of the country. They have two long, tubular appendages on the tail end of their body.
Life Cycle
Aphid eggs overwinter attached to plants, then hatch as nymphs in the spring.
These nymphs then produce eggs asexually, producing more nymphs that grow to maturity in just one week. Then, in the fall the nymphs will lay eggs that contain some male aphids. These males then mate with the nymphs to produce the eggs that will overwinter and start the next generation of aphids. Mature aphids lay three to six eggs per day. The rapid asexual reproduction cycle during the growing season is what leads to the rapid and widespread infestation so familiar to many gardeners.
Signs of Aphid Infestation
Aphids suck the sap out of tender plant shoots and leaves using beak-like mouths, injecting the leaves with their saliva as they do so. The damage to plants is twofold: drinking the sap can weaken the plant, and injecting the saliva can spread diseases from plant to plant. In addition, aphids excrete a sticky, clear substance called "honey dew" which commonly fosters the development sooty mold.
Sooty mold is unsightly and interferes with the plant's ability to photosynthesize.
Because aphids are so tiny, sometimes the first sign that massive infestation is pending is the sign of many ants on your plants. The honeydew secretion is much prized as a food by ants, so when you see many ants on plants, there is a very good likelihood that aphids are also present.
Effect on Garden Plants
Aphids can weaken a plant, stunt its growth, cause leaves to curl or wilt, and delay fruit or flower production. In general, an overall anemic appearance to your plants when there is not water shortage or other obvious reason will strongly hint that aphids are to blame.
Organic Controls for Aphids
There are a number of non-chemical ways to combat or discourage aphid infestations.
Sometimes, a strong blast of water from the hose will knock the aphids off of a plant and solve the problem.
If you attract or purchase certain beneficial insects, such as lady bugs, lacewings, parasitic wasps or damsel bugs, they will attack the aphids. For this reason, fewer chemical pesticides used in the garden can paradoxically reduce the severity of aphid infestations. A more diverse insect population generally keeps aphid attacks at bay. Plantings mint, fennel, dill, yarrow and dandelions will attract these predators to your garden. Ants are natural enemies of predatory insects, so you may need to control ants in order to maximize the hunting ability of the beneficials.
Plants can also be sprayed with insecticidal soap, or a homemade tomato leaf or garlic spray to kill aphids, but must be reapplied when the infestations reappear.
Some biological insecticides based on fungi are known to work on aphids.
If You Use Chemical Solutions
Aphids are easily killed by standard chemical pesticides, but because they are so prolific and will reinfest so readily, gardeners who try to rely on chemicals often find that their problems are intensified over the long run, as the chemicals must be reapplied often and will also destroy populations of beneficial insects and discourage other aphid predators, such as insect-eating birds.
Many gardeners find that an adapted form of the integrated pest management (IPM) practice used by commercial agriculture is a good approach for home gardening. Under this philosophy, some degree of plant damage is deemed acceptable as the price paid for a diverse gardening culture in which the presence of many insect species tends to prevent any one pest from causing overwhelming damage.
Over the long run, minimal use of chemical pesticides tends to produce an overall healthier garden, albeit one in which small levels of insect damage may be present.
Garden aphids, also known as plant lice, include many different species in the Aphidoidea insect family. Aphids are very small--roughly 1/10th of an inch long. The most common colors are green and black, though brown, reddish-brown, and gray aphids inhabit some parts of the country. They have two long, tubular appendages on the tail end of their body.
Life Cycle
Aphid eggs overwinter attached to plants, then hatch as nymphs in the spring.
These nymphs then produce eggs asexually, producing more nymphs that grow to maturity in just one week. Then, in the fall the nymphs will lay eggs that contain some male aphids. These males then mate with the nymphs to produce the eggs that will overwinter and start the next generation of aphids. Mature aphids lay three to six eggs per day. The rapid asexual reproduction cycle during the growing season is what leads to the rapid and widespread infestation so familiar to many gardeners.
Signs of Aphid Infestation
Aphids suck the sap out of tender plant shoots and leaves using beak-like mouths, injecting the leaves with their saliva as they do so. The damage to plants is twofold: drinking the sap can weaken the plant, and injecting the saliva can spread diseases from plant to plant. In addition, aphids excrete a sticky, clear substance called "honey dew" which commonly fosters the development sooty mold.
Sooty mold is unsightly and interferes with the plant's ability to photosynthesize.
Because aphids are so tiny, sometimes the first sign that massive infestation is pending is the sign of many ants on your plants. The honeydew secretion is much prized as a food by ants, so when you see many ants on plants, there is a very good likelihood that aphids are also present.
Effect on Garden Plants
Aphids can weaken a plant, stunt its growth, cause leaves to curl or wilt, and delay fruit or flower production. In general, an overall anemic appearance to your plants when there is not water shortage or other obvious reason will strongly hint that aphids are to blame.
Organic Controls for Aphids
There are a number of non-chemical ways to combat or discourage aphid infestations.
Sometimes, a strong blast of water from the hose will knock the aphids off of a plant and solve the problem.
If you attract or purchase certain beneficial insects, such as lady bugs, lacewings, parasitic wasps or damsel bugs, they will attack the aphids. For this reason, fewer chemical pesticides used in the garden can paradoxically reduce the severity of aphid infestations. A more diverse insect population generally keeps aphid attacks at bay. Plantings mint, fennel, dill, yarrow and dandelions will attract these predators to your garden. Ants are natural enemies of predatory insects, so you may need to control ants in order to maximize the hunting ability of the beneficials.
Plants can also be sprayed with insecticidal soap, or a homemade tomato leaf or garlic spray to kill aphids, but must be reapplied when the infestations reappear.
Some biological insecticides based on fungi are known to work on aphids.
If You Use Chemical Solutions
Aphids are easily killed by standard chemical pesticides, but because they are so prolific and will reinfest so readily, gardeners who try to rely on chemicals often find that their problems are intensified over the long run, as the chemicals must be reapplied often and will also destroy populations of beneficial insects and discourage other aphid predators, such as insect-eating birds.
Many gardeners find that an adapted form of the integrated pest management (IPM) practice used by commercial agriculture is a good approach for home gardening. Under this philosophy, some degree of plant damage is deemed acceptable as the price paid for a diverse gardening culture in which the presence of many insect species tends to prevent any one pest from causing overwhelming damage.
Over the long run, minimal use of chemical pesticides tends to produce an overall healthier garden, albeit one in which small levels of insect damage may be present.
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文章
Dummer. ゛☀
2017年09月13日
Citrus mealybugs, first identified in the U.S. in 1879 can infest and destroy greenhouse and outdoor crops of plant hosts such as Tulips, Cannas, Begonias, Narcissus and Coleus.
Identification
Host plants may be dropping leaves, have distorted growth or areas of mold and waxy cottony secretions. Although they are tiny, less than 5 mm long (25.4 mm per inch), wingless female mealybugs with peripheral body filaments or winged males with tail filaments may be lurking and munching in plant crevices, looking as if they had been rolled in flour and ready to be tossed into a micro-sized frying pan.
Damage
The mealybugs suck out the host plants sap, injecting toxic saliva and secreting honeydew that grows mold and a cottony wax that can disfigure flowers and make them unsuitable for the market, dining room table or kitchen windowsill. Ants who feast on the tasty honeydew ferry the wingless females to neighboring plants.
Control
A first and final defense is to destroy the infested plants as mealybug infestations can be fatal to the host plant if left untreated. A second and less radical approach is to employ beneficial insects, such as Mealybug Destroyer beetles which feed voraciously on the pests and can be purchased from commercial suppliers.
Note: Like the pest insect, these beetles do not survive cold weather so they must either be released into greenhouses, outdoors in temperate climates or outdoors during warm seasons in colder climes. In addition, birds will prey on the beetles outdoors.
Also, spreading bone meal at the base of any plants or wrapping the trunk in cloth may discourage ants from visiting and spreading the tenacious pests.
Neighborhood Watch
Other botanical derivatives such as Rotenone and Pyrethrum have been effective in some applications and controls that work in one location may not work in another, so ask other local organic gardeners or the county extension service for suggestions.
Identification
Host plants may be dropping leaves, have distorted growth or areas of mold and waxy cottony secretions. Although they are tiny, less than 5 mm long (25.4 mm per inch), wingless female mealybugs with peripheral body filaments or winged males with tail filaments may be lurking and munching in plant crevices, looking as if they had been rolled in flour and ready to be tossed into a micro-sized frying pan.
Damage
The mealybugs suck out the host plants sap, injecting toxic saliva and secreting honeydew that grows mold and a cottony wax that can disfigure flowers and make them unsuitable for the market, dining room table or kitchen windowsill. Ants who feast on the tasty honeydew ferry the wingless females to neighboring plants.
Control
A first and final defense is to destroy the infested plants as mealybug infestations can be fatal to the host plant if left untreated. A second and less radical approach is to employ beneficial insects, such as Mealybug Destroyer beetles which feed voraciously on the pests and can be purchased from commercial suppliers.
Note: Like the pest insect, these beetles do not survive cold weather so they must either be released into greenhouses, outdoors in temperate climates or outdoors during warm seasons in colder climes. In addition, birds will prey on the beetles outdoors.
Also, spreading bone meal at the base of any plants or wrapping the trunk in cloth may discourage ants from visiting and spreading the tenacious pests.
Neighborhood Watch
Other botanical derivatives such as Rotenone and Pyrethrum have been effective in some applications and controls that work in one location may not work in another, so ask other local organic gardeners or the county extension service for suggestions.
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文章
Dummer. ゛☀
2017年09月13日
HESE small, soft-bodied, pear-shaped insects cluster densely on tender new growth and the undersides of leaves to suck plant juices. Plants often can withstand some aphid feeding with no adverse effect, but badly infested plants develop distorted growth and leaves may turn yellow or drop off.
Sometimes it takes close inspection to discover an aphid infestation. They blend in so well with foliage that you may not spot them at first glance, even though hundreds are present. Many species of aphids feed on home garden plants; these insects range in color from pale green, pink, or black to red or yellow. Size is typically 1/16″–1/4″. Adult aphids are generally wingless, but winged adults will appear when overcrowded. Immature aphids (nymphs) closely resemble adults.
Both adults and nymphs feed on a wide variety of plants, including most edibles and ornamentals. In small numbers aphids do little damage, but they are able to reproduce rapidly and can quickly become a more serious problem. Also, as they feed, aphids secrete a sweet fluid called honeydew that can attract ants; sooty black fungus may grow on coated leaves. Aphids are common throughout the U.S.
Prevention and control
When fertilizing your garden, avoid applying too much nitrogen, which can stimulate plants to grow too rapidly and produce a flush of exactly the kind of tender new growth that aphids love.
Attract and release beneficial insects, such as ladybugs and lacewings, which will be happy to devour a bountiful supply of aphids.
Use a spray with neem oil, which is derived from the seed of the neem tree. It controls a wide variety of common garden insect pests such as aphids as well as fungal diseases.
Use a strong spray of water from your hose to dislodge aphids from affected plants. This will reduce their numbers dramatically. Recheck the plants a few days later and repeat the treatment if needed. (Keep in mind that water sprays will also kill beneficial insects.)
Sometimes it takes close inspection to discover an aphid infestation. They blend in so well with foliage that you may not spot them at first glance, even though hundreds are present. Many species of aphids feed on home garden plants; these insects range in color from pale green, pink, or black to red or yellow. Size is typically 1/16″–1/4″. Adult aphids are generally wingless, but winged adults will appear when overcrowded. Immature aphids (nymphs) closely resemble adults.
Both adults and nymphs feed on a wide variety of plants, including most edibles and ornamentals. In small numbers aphids do little damage, but they are able to reproduce rapidly and can quickly become a more serious problem. Also, as they feed, aphids secrete a sweet fluid called honeydew that can attract ants; sooty black fungus may grow on coated leaves. Aphids are common throughout the U.S.
Prevention and control
When fertilizing your garden, avoid applying too much nitrogen, which can stimulate plants to grow too rapidly and produce a flush of exactly the kind of tender new growth that aphids love.
Attract and release beneficial insects, such as ladybugs and lacewings, which will be happy to devour a bountiful supply of aphids.
Use a spray with neem oil, which is derived from the seed of the neem tree. It controls a wide variety of common garden insect pests such as aphids as well as fungal diseases.
Use a strong spray of water from your hose to dislodge aphids from affected plants. This will reduce their numbers dramatically. Recheck the plants a few days later and repeat the treatment if needed. (Keep in mind that water sprays will also kill beneficial insects.)
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