文章
Dummer. ゛☀
2017年08月08日
Shot hole disease, which may also be known as Coryneum blight, is a serious issue in many fruit trees. It is most commonly seen in peach, nectarine, apricot, and plum trees but may also affect almond and prune trees. Some flowering ornamental trees can be affected as well. Since little can be done to control shot hole fungus once the trees have been infected, prevention is essential in treating shot hole disease.
Signs of Shot Hole Fungus
Shot hole disease thrives in wet conditions, especially during extended wet periods. The disease is most noticeable in spring, as new growth is most susceptible. Shot hole fungus commonly overwinters inside the infected buds, as well as twig lesions, where the spores may thrive for several months. Therefore, it is important to thoroughly inspect trees after leaf fall for any symptoms. Most signs of shot hole disease occur in spring, causing spots (or lesions) on new buds and young leaves and shoots. Buds will have a varnished appearance and spots will first look reddish or purplish-brown in color and about ¼ inch in diameter. Eventually, these spots become larger, turning brown and falling out—giving the appearance of gunshot holes in the foliage. As it progresses, the leaves will drop. The stress also affects the tree’s ability to produce, and any fruit that may develop will usually be affected as well with spotting on the upper surface that may even become rough.
Shot Hole Disease Treatment
Infections can occur anytime between fall and spring, but is usually most severe following wet winters. Prolonged spring rains can also encourage this disease, as spores are spread from the splashing rain. Overhead watering may also contribute to the disease. Good sanitation is key to treating shot hole disease naturally. This is the surest way to keep the disease from coming back. All infected buds, blossoms, fruit, and twigs need to be promptly removed and destroyed. Contaminated leaves around and beneath the tree should be removed as well.
Applying dormant spray — Bordeaux or fixed copper fungicide — in late fall is advisable, following the label instructions carefully. These sprays should not be applied in spring once new growth appears but additional applications may be necessary during wet weather.
Signs of Shot Hole Fungus
Shot hole disease thrives in wet conditions, especially during extended wet periods. The disease is most noticeable in spring, as new growth is most susceptible. Shot hole fungus commonly overwinters inside the infected buds, as well as twig lesions, where the spores may thrive for several months. Therefore, it is important to thoroughly inspect trees after leaf fall for any symptoms. Most signs of shot hole disease occur in spring, causing spots (or lesions) on new buds and young leaves and shoots. Buds will have a varnished appearance and spots will first look reddish or purplish-brown in color and about ¼ inch in diameter. Eventually, these spots become larger, turning brown and falling out—giving the appearance of gunshot holes in the foliage. As it progresses, the leaves will drop. The stress also affects the tree’s ability to produce, and any fruit that may develop will usually be affected as well with spotting on the upper surface that may even become rough.
Shot Hole Disease Treatment
Infections can occur anytime between fall and spring, but is usually most severe following wet winters. Prolonged spring rains can also encourage this disease, as spores are spread from the splashing rain. Overhead watering may also contribute to the disease. Good sanitation is key to treating shot hole disease naturally. This is the surest way to keep the disease from coming back. All infected buds, blossoms, fruit, and twigs need to be promptly removed and destroyed. Contaminated leaves around and beneath the tree should be removed as well.
Applying dormant spray — Bordeaux or fixed copper fungicide — in late fall is advisable, following the label instructions carefully. These sprays should not be applied in spring once new growth appears but additional applications may be necessary during wet weather.
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文章
Dummer. ゛☀
2017年08月08日
Bacterial soft rot disease is an infection that can devastate a crop of fleshy vegetables such as carrots, onions, tomatoes and cucumbers, though it is most widely known for its attacks on potatoes. Soft rot disease is most easily recognized in these vegetables by soft, wet, cream to tan colored flesh surrounded by a dark brown to black ring. When conditions are right, these necrotic spots begin on the outside or skin of the potato and works inward. Initially, there is no odor, but as the soft rot disease progresses, secondary infections invade and the blackened potato emits a foul smell. These symptoms are similar in most other affected plants as well with small, water-soaked, translucent spots on leaves, stems or underground parts.
What is Bacterial Soft Rot?
Soft rot bacteria, or Erwinia cartovorum is, unfortunately, found everywhere. It survives in soil and water sources, even oceans, and is found all over the globe. Almost all commercial crops are affected to some degree by soft rot. Bacteria in the home garden can be introduced by insects, wind blown rain, or leftovers from the previous year’s crop. One of the most common culprits on potatoes is the seed potato itself. The soft rot bacteria can be found on almost all tubers but most commonly affects potatoes. The infection occurs through skin damage due to growth cracks or injury and high soil temperatures combined with excess water provides the perfect growing conditions. Very often, signs of bacterial soft rot will not occur until after harvest. This is largely due to improper handling of the newly harvested potatoes. There is no completely effective soft rot treatment, but there are things you can do to minimize the damage.
Tips for Controlling Soft Rot Bacteria
Once soft rot bacteria have infected plants in the garden, there is no effective treatment. You will need to remove and dispose of infected plants as soon as possible to avoid further damage to other plants. Prevention is key in controlling soft rot bacteria. The following steps can be taken to help avoid this problem in the garden: Avoid wet conditions. Make sure plants are in well-draining soil and properly spaced. Keep track of watering to prevent too much moisture. Rotate crops with rot-resistant vegetables. Crop rotation goes a long way in managing or preventing problems in the garden. When rotating crops, select varieties that are less susceptible to soft rot like corn, snap beans and beets. If you have had previous issues with soft rot disease in the past, wait at least three years before growing susceptible crops in that area. Use caution during garden maintenance. As you go about normal weeding tasks, or even harvesting, take care not to damage plants or veggies. Harvest only when conditions are dry and closely examine vegetables for any signs of problems that may affect storage, which should be in a cool, dry and well ventilated location. Keep the garden and tools clean. Be sure to clean garden tools thoroughly before and after use to avoid spreading any potential disease and always remove any infected/damaged plant debris remaining in your garden once the season is over.
What is Bacterial Soft Rot?
Soft rot bacteria, or Erwinia cartovorum is, unfortunately, found everywhere. It survives in soil and water sources, even oceans, and is found all over the globe. Almost all commercial crops are affected to some degree by soft rot. Bacteria in the home garden can be introduced by insects, wind blown rain, or leftovers from the previous year’s crop. One of the most common culprits on potatoes is the seed potato itself. The soft rot bacteria can be found on almost all tubers but most commonly affects potatoes. The infection occurs through skin damage due to growth cracks or injury and high soil temperatures combined with excess water provides the perfect growing conditions. Very often, signs of bacterial soft rot will not occur until after harvest. This is largely due to improper handling of the newly harvested potatoes. There is no completely effective soft rot treatment, but there are things you can do to minimize the damage.
Tips for Controlling Soft Rot Bacteria
Once soft rot bacteria have infected plants in the garden, there is no effective treatment. You will need to remove and dispose of infected plants as soon as possible to avoid further damage to other plants. Prevention is key in controlling soft rot bacteria. The following steps can be taken to help avoid this problem in the garden: Avoid wet conditions. Make sure plants are in well-draining soil and properly spaced. Keep track of watering to prevent too much moisture. Rotate crops with rot-resistant vegetables. Crop rotation goes a long way in managing or preventing problems in the garden. When rotating crops, select varieties that are less susceptible to soft rot like corn, snap beans and beets. If you have had previous issues with soft rot disease in the past, wait at least three years before growing susceptible crops in that area. Use caution during garden maintenance. As you go about normal weeding tasks, or even harvesting, take care not to damage plants or veggies. Harvest only when conditions are dry and closely examine vegetables for any signs of problems that may affect storage, which should be in a cool, dry and well ventilated location. Keep the garden and tools clean. Be sure to clean garden tools thoroughly before and after use to avoid spreading any potential disease and always remove any infected/damaged plant debris remaining in your garden once the season is over.
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文章
Dummer. ゛☀
2017年08月08日
A common but under diagnosed problem in the spring garden is a disease called downy mildew. This disease can damage or stunt plants and is difficult to diagnose. But, if you are familiar with the different ways this disease presents itself and with the conditions it which is can grow in, you will be better able to take steps to control downy mildew in your garden.
What is Downy Mildew?
Often times, when gardeners hear the name downy mildew, they think this disease is related to another common garden disease called powdery mildew. While the two have very similar names, they are two very different diseases. Downy mildew is caused mostly by organisms that belong to either the Peronospora or Plasmopara genus. While powdery mildew is cause by a true fungus, downy mildew is cause by parasitic organisms that are more closely related to algae. Because it is closely related to algae, downy mildew needs water to survive and spread. It also needs cooler temperatures. You are most likely to see downy mildew in your plants in the spring, where rainfall is frequent and temperatures stay cool.
Symptoms of Downy Mildew
One of the tricky things about downy mildew is that it can appear different ways, depending on what kinds of plants it is infecting. Most often, an infection of downy mildew will also include a fuzzy, soft looking growth that can be white, grey, brown or purple. This growth is most commonly seen on the lower leaves of the plant. This growth is where this disease gets its name from, due to its downy appearance. Other common symptoms for downy mildew include mottling or spots on the leaves. The spotting will be yellow, light green, brown, black or purple. In some cases, the mottling may look like chlorosis. Plants that are affected by downy mildew, may be stunted or have leaf loss.
Controlling Downy Mildew
The best control of downy mildew is to make sure that your plants do not get it in the first place. Because downy mildew needs water to survive, the very best thing you can do to prevent downy mildew is to water your plants from below. Water that sits on the leaves of the plant gives the downy mildew a way to infect and spread on the plant. The spore of downy mildews spreads by literally swimming through water until they come across live plant material to infect. If there is no water on your plant leaves, the downy mildew cannot travel to or infect your plants. Good garden hygiene is also crucial to stopping downy mildew from developing in your garden. This disease overwinters on dead plant material, so removing dead plant material from your garden in the fall will help prevent the disease in the following spring. If your plants become infected with downy mildew, the organic control of downy mildew is your best bet. The reason is that once a plant is infected with downy mildew, there are no effective chemical controls, though if you have a reoccurring problem with downy mildew, there are some preventative chemicals you can use. Downy mildew is not a fungus, so fungicides will not work on it. Once your plants have downy mildew, the best thing you can do is to try to eliminate moisture and humidity around the plants. As mentioned, make sure your are watering from below. If possible, try to improve air circulation through selective pruning. In enclosed environments, like in the house or in a greenhouse, reducing the humidity will help as well. Regardless of what you do, downy mildew normally clears itself up in the outdoor garden once the weather warms up, as this disease does not survive well in warm temperatures. If your plants only have a mild case of downy mildew, your best option may be to simply wait for warmer weather.
What is Downy Mildew?
Often times, when gardeners hear the name downy mildew, they think this disease is related to another common garden disease called powdery mildew. While the two have very similar names, they are two very different diseases. Downy mildew is caused mostly by organisms that belong to either the Peronospora or Plasmopara genus. While powdery mildew is cause by a true fungus, downy mildew is cause by parasitic organisms that are more closely related to algae. Because it is closely related to algae, downy mildew needs water to survive and spread. It also needs cooler temperatures. You are most likely to see downy mildew in your plants in the spring, where rainfall is frequent and temperatures stay cool.
Symptoms of Downy Mildew
One of the tricky things about downy mildew is that it can appear different ways, depending on what kinds of plants it is infecting. Most often, an infection of downy mildew will also include a fuzzy, soft looking growth that can be white, grey, brown or purple. This growth is most commonly seen on the lower leaves of the plant. This growth is where this disease gets its name from, due to its downy appearance. Other common symptoms for downy mildew include mottling or spots on the leaves. The spotting will be yellow, light green, brown, black or purple. In some cases, the mottling may look like chlorosis. Plants that are affected by downy mildew, may be stunted or have leaf loss.
Controlling Downy Mildew
The best control of downy mildew is to make sure that your plants do not get it in the first place. Because downy mildew needs water to survive, the very best thing you can do to prevent downy mildew is to water your plants from below. Water that sits on the leaves of the plant gives the downy mildew a way to infect and spread on the plant. The spore of downy mildews spreads by literally swimming through water until they come across live plant material to infect. If there is no water on your plant leaves, the downy mildew cannot travel to or infect your plants. Good garden hygiene is also crucial to stopping downy mildew from developing in your garden. This disease overwinters on dead plant material, so removing dead plant material from your garden in the fall will help prevent the disease in the following spring. If your plants become infected with downy mildew, the organic control of downy mildew is your best bet. The reason is that once a plant is infected with downy mildew, there are no effective chemical controls, though if you have a reoccurring problem with downy mildew, there are some preventative chemicals you can use. Downy mildew is not a fungus, so fungicides will not work on it. Once your plants have downy mildew, the best thing you can do is to try to eliminate moisture and humidity around the plants. As mentioned, make sure your are watering from below. If possible, try to improve air circulation through selective pruning. In enclosed environments, like in the house or in a greenhouse, reducing the humidity will help as well. Regardless of what you do, downy mildew normally clears itself up in the outdoor garden once the weather warms up, as this disease does not survive well in warm temperatures. If your plants only have a mild case of downy mildew, your best option may be to simply wait for warmer weather.
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文章
Dummer. ゛☀
2017年08月08日
Also called Staghead or white blister, white rust disease affects cruciferous plants. These plants are all members of the cabbage family (Brassicaceae) and include such vegetables as broccoli, cauliflower, Brussels sprouts and kale and can ruin your crop.
White Rust Disease – What is White Rust?
What is white rust? It’s a disease that causes distinctive chalky white spore masses sometimes referred to as pustules that first show up on the underside of leaves. These blister-like masses, called sori, form under the leaf’s dermis (skin) and can’t be scraped off without damaging the leaf. The stem and leaves can become twisted and deformed. White rust disease can and will infect the floral parts as well. Broccoli and cauliflower, in particular, will produce grossly deformed heads and for those gardeners who collect seed for the following year’s planting, those seeds will be sterile. White rust is one of several species of the fungus Albugo. It commonly occurs when nights are cool and damp and days are warm. The perfect time for growing cruciferous vegetables also provides the perfect growing conditions for Albugo. Controlling white rust fungus would be easy if we could control those spring and fall temperatures since it flourishes between 57°F. and 68°F. (14° to 20°C.). Unfortunately, we can’t control temperature any more than we can control the spring rains or the dewy mornings this fungus adores.
White Rust Treatment
If your garden has been plagued by white rust disease in the past, you should look for resistant strains in the future. There are no fungicides specific to white rust treatment and once the disease becomes rampant, there is little to be done. That being said, fungicides used to treat downy mildew are sometimes effective against white rust, particularly the more leafy crops. Treatment must begin at the first signs of infection. The methods for controlling white rust fungus or how to prevent white rust are largely organic. The control of white rust fungus depends on the understanding of the life cycle of fungi in general. Fungi reproduce by producing spores, tiny microscopic cells, each of which is capable of becoming a fungi and thus establishing a new colony — what we see on the leaf or stem. Because of their minuscule size, these spores are carried easily from plant to plant, or garden to garden, by wind or water. Because of a protective coating, many of these spores can lay dormant for long periods of time, surviving in both cold and arid conditions. When conditions are right again, they ‘blossom.’ The secret to how to prevent white rust is two-fold. First is the removal of the places where the spores hide. Garden debris should never be left to overwinter. Even plant growth that looks healthy may be harboring spores waiting to spread the disease the following spring. Obviously infected debris should be disposed of away from the garden area. As it is almost impossible to collect and destroy every scrap of debris, consider tilling it under as another form of white rust treatment. While tilling won’t destroy the spores, it can prevent them from being exposed to the growing conditions they require.
he second step in controlling white rust fungus is crop rotation. Infected beds should not be replanted with cruciferous vegetables for at least three years. Remember, good garden housekeeping is essential in controlling white rust fungus as well as many other garden diseases; therefore, it should be a regular part of your gardening calendar. That old adage remains true: An ounce of prevention is worth a pound of cure.
White Rust Disease – What is White Rust?
What is white rust? It’s a disease that causes distinctive chalky white spore masses sometimes referred to as pustules that first show up on the underside of leaves. These blister-like masses, called sori, form under the leaf’s dermis (skin) and can’t be scraped off without damaging the leaf. The stem and leaves can become twisted and deformed. White rust disease can and will infect the floral parts as well. Broccoli and cauliflower, in particular, will produce grossly deformed heads and for those gardeners who collect seed for the following year’s planting, those seeds will be sterile. White rust is one of several species of the fungus Albugo. It commonly occurs when nights are cool and damp and days are warm. The perfect time for growing cruciferous vegetables also provides the perfect growing conditions for Albugo. Controlling white rust fungus would be easy if we could control those spring and fall temperatures since it flourishes between 57°F. and 68°F. (14° to 20°C.). Unfortunately, we can’t control temperature any more than we can control the spring rains or the dewy mornings this fungus adores.
White Rust Treatment
If your garden has been plagued by white rust disease in the past, you should look for resistant strains in the future. There are no fungicides specific to white rust treatment and once the disease becomes rampant, there is little to be done. That being said, fungicides used to treat downy mildew are sometimes effective against white rust, particularly the more leafy crops. Treatment must begin at the first signs of infection. The methods for controlling white rust fungus or how to prevent white rust are largely organic. The control of white rust fungus depends on the understanding of the life cycle of fungi in general. Fungi reproduce by producing spores, tiny microscopic cells, each of which is capable of becoming a fungi and thus establishing a new colony — what we see on the leaf or stem. Because of their minuscule size, these spores are carried easily from plant to plant, or garden to garden, by wind or water. Because of a protective coating, many of these spores can lay dormant for long periods of time, surviving in both cold and arid conditions. When conditions are right again, they ‘blossom.’ The secret to how to prevent white rust is two-fold. First is the removal of the places where the spores hide. Garden debris should never be left to overwinter. Even plant growth that looks healthy may be harboring spores waiting to spread the disease the following spring. Obviously infected debris should be disposed of away from the garden area. As it is almost impossible to collect and destroy every scrap of debris, consider tilling it under as another form of white rust treatment. While tilling won’t destroy the spores, it can prevent them from being exposed to the growing conditions they require.
he second step in controlling white rust fungus is crop rotation. Infected beds should not be replanted with cruciferous vegetables for at least three years. Remember, good garden housekeeping is essential in controlling white rust fungus as well as many other garden diseases; therefore, it should be a regular part of your gardening calendar. That old adage remains true: An ounce of prevention is worth a pound of cure.
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文章
Dummer. ゛☀
2017年08月08日
Gummy stem blight is a fungal disease of melons, cucumbers and other cucurbits. It is a contagious disease which can spread across a field of fruits. The fungus damages the tissues of the stem at all stages of development. Stem blight treatment must start before you even plant the seeds to be entirely effective. Find out what is gummy stem blight so you can prevent this problem in your vegetable garden. What is Gummy Stem Blight Disease? Gummy stem blight fungus is most active during periods of warm, wet weather. The spores of the fungus can spread in soil or by air. The fungus will overwinter in milder climates in soil and plant debris. The leaves will get necrotic areas of dead tissue that turn brown and have a darker halo. The stems and fruit will show black, soft spots or large brown lesions that are bordered by black. The dark coloring of these lesions also lends the disease the name of black rot fungus.
Black Rot Fungus Characteristics
Stem blight forms when seeds or sites are previously infected with the fungal spores. When conditions are 85 percent humid or wet and warm, with temperatures averaging in the 60’s, (16-21 C.), the fungal spores bloom. You should start treating black rot fungus at the first signs of the disease. Unfortunately, the first signs vary dependent upon plant species. Many get water spotting on the foliage or stems may ooze black or brown gummy beads of fluid. It is difficult to identify these early signs of gummy stem blight, which is why preparation of the seedbed, purchasing resistant seeds and rotating crops are important prequels to stem blight treatment. Ultimately, plants affected by this disease will bear rotten fruits, which are unmistakable and inedible.
Prevention of Gummy Stem Blight
The first stages of a disease free cucurbit crop are preparation and rotation. Never plant cucumbers, melons or other susceptible plants in the same area as the previous season’s crop. The plant debris, and even seeds, left over in the soil will harbor the spores of black rot fungus. Careful preparation of soil prior to planting removes all old organic matter. Use seeds from a reputable seed company that has a history of fungus-free seeds. Since the disease can manifest even on seedlings, inspect any that you have purchased from a nursery prior to purchase and planting. Gummy stem blight signs on seedlings are brown lesions and dry leaf edges. Do not plant suspect specimens.
Treating Black Rot Fungus
In most cases, removal of old plant debris, rotation and resistant species will prevent the appearance of gummy stem blight. In climates with warm, moist bloom conditions, the fungal spores are carried on the wind and you may have to combat the disease even if you took preventative steps. The most common method is the use of fungicides as a stem blight treatment. Dusts or sprays of fungicides useful for preventing and combating powdery or downy mildew have been shown to be effective against gummy stem blight disease.
Black Rot Fungus Characteristics
Stem blight forms when seeds or sites are previously infected with the fungal spores. When conditions are 85 percent humid or wet and warm, with temperatures averaging in the 60’s, (16-21 C.), the fungal spores bloom. You should start treating black rot fungus at the first signs of the disease. Unfortunately, the first signs vary dependent upon plant species. Many get water spotting on the foliage or stems may ooze black or brown gummy beads of fluid. It is difficult to identify these early signs of gummy stem blight, which is why preparation of the seedbed, purchasing resistant seeds and rotating crops are important prequels to stem blight treatment. Ultimately, plants affected by this disease will bear rotten fruits, which are unmistakable and inedible.
Prevention of Gummy Stem Blight
The first stages of a disease free cucurbit crop are preparation and rotation. Never plant cucumbers, melons or other susceptible plants in the same area as the previous season’s crop. The plant debris, and even seeds, left over in the soil will harbor the spores of black rot fungus. Careful preparation of soil prior to planting removes all old organic matter. Use seeds from a reputable seed company that has a history of fungus-free seeds. Since the disease can manifest even on seedlings, inspect any that you have purchased from a nursery prior to purchase and planting. Gummy stem blight signs on seedlings are brown lesions and dry leaf edges. Do not plant suspect specimens.
Treating Black Rot Fungus
In most cases, removal of old plant debris, rotation and resistant species will prevent the appearance of gummy stem blight. In climates with warm, moist bloom conditions, the fungal spores are carried on the wind and you may have to combat the disease even if you took preventative steps. The most common method is the use of fungicides as a stem blight treatment. Dusts or sprays of fungicides useful for preventing and combating powdery or downy mildew have been shown to be effective against gummy stem blight disease.
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文章
Dummer. ゛☀
2017年08月08日
If you’ve noticed frothy-like foam seeping from your tree, then it has likely been affected by alcoholic flux. While there is no real treatment for the disease, preventing alcoholic flux may be your only option to avoid future outbreaks. Keep reading to learn more frothy flux info. What is Alcoholic Flux? Alcoholic flux is a stress-related disease that affects sweet gum, oak, elm and willow trees. It usually occurs after a period of very hot, dry weather. The disease is caused by a microorganism that ferments the sap that seeps or bleeds from cracks and wounds in the bark. The result is a white, frothy ooze that has a sweet, fermenting odor similar to beer. Alcoholic flux is sometimes called frothy flux or foamy canker because of the white ooze that looks and feels like melted marshmallows. Fortunately, this ooze only lasts for a short time in summer.
Frothy Flux Info and Prevention
Anything that promotes the overall good health of the tree aids in preventing alcoholic flux. Symptoms usually occur after a period of extremely hot, dry weather, so water the tree deeply during dry spells. Apply the water slowly to encourage absorption to a depth of 18 to 24 inches. Water the entire area under the canopy of the tree and cover the root zone with mulch to cut down on water evaporation and keep the roots cool. A good annual fertilization program helps keep trees healthy and able to resist disease. For mature trees, this means at least one feeding a year, usually in late winter or early spring as the leaves begin to bud. Young trees benefit from two or three smaller feedings over spring and summer. Wounds and cracks in the bark make it easier for the microorganism to enter the tree. Also, you should prune damaged and diseased limbs back to the collar. Use alcohol, a 10 percent bleach solution or a household disinfectant to clean the pruning tools between cuts so that your tools don’t spread disease to other parts of the tree. Take care when using a string trimmer around the tree, and mow the grass so that debris flies away from the tree rather than toward it to avoid chips in the bark.
Alcoholic Flux Treatment Unfortunately, there is no effective alcoholic flux treatment, but the symptoms only last a short while in a healthy tree. In severe cases, the layer of wood under the bark may become rotten and mushy. If the tree doesn’t recover properly, it should be cut down.
Frothy Flux Info and Prevention
Anything that promotes the overall good health of the tree aids in preventing alcoholic flux. Symptoms usually occur after a period of extremely hot, dry weather, so water the tree deeply during dry spells. Apply the water slowly to encourage absorption to a depth of 18 to 24 inches. Water the entire area under the canopy of the tree and cover the root zone with mulch to cut down on water evaporation and keep the roots cool. A good annual fertilization program helps keep trees healthy and able to resist disease. For mature trees, this means at least one feeding a year, usually in late winter or early spring as the leaves begin to bud. Young trees benefit from two or three smaller feedings over spring and summer. Wounds and cracks in the bark make it easier for the microorganism to enter the tree. Also, you should prune damaged and diseased limbs back to the collar. Use alcohol, a 10 percent bleach solution or a household disinfectant to clean the pruning tools between cuts so that your tools don’t spread disease to other parts of the tree. Take care when using a string trimmer around the tree, and mow the grass so that debris flies away from the tree rather than toward it to avoid chips in the bark.
Alcoholic Flux Treatment Unfortunately, there is no effective alcoholic flux treatment, but the symptoms only last a short while in a healthy tree. In severe cases, the layer of wood under the bark may become rotten and mushy. If the tree doesn’t recover properly, it should be cut down.
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文章
Dummer. ゛☀
2017年08月08日
Before you decide to start crown gall treatment, consider the value of the plant you are treating. The bacteria that causes crown gall disease in plants persists in the soil as long as there are susceptible plants in the area. To eliminate the bacteria and prevent the spread, it’s best to remove and destroy diseased plants. What is Crown Gall? When learning about crown gall treatment, it helps to know more about what is crown gall in the first place. Plants with crown gall have swollen knots, called galls, near the crown and sometimes on the roots and twigs as well. The galls are tan in color and may be spongy in texture at first, but they eventually harden and turn dark brown or black. As the disease progresses, the galls can totally encircle the trunks and branches, cutting off the flow of sap that nourishes the plant. The galls are caused by a bacterium (Rhizobium radiobacter formerly Agrobacterium tumefaciens) that lives in the soil and enters the plant through injuries. Once inside the plant, the bacterium injects some of its genetic material into the host’s cells, causing it to produce hormones that stimulate small areas of rapid growth.
How to Fix Crown Gall
Unfortunately, the best course of action for plants affected by crown gall is to remove and destroy the infected plant. The bacteria can persist in the soil for two years after the plant is gone, so avoid planting any other susceptible plants in the area until the bacteria dies out for lack of a host plant. Prevention is an essential aspect of dealing with crown gall. Inspect plants carefully before you buy them, and reject any plants with swollen knots. The disease can enter the plant in the nursery through the graft union, so pay particular attention to this area.
To prevent the bacteria from entering the plant once you get it home, avoid wounds near the ground as much as possible. Use string trimmers with care and mow the lawn so that debris flies away from susceptible plants. Galltrol is a product that contains a bacterium that competes with Rhizobium radiobacter and prevents it from entering wounds. A chemical eradicant called Gallex may also help prevent the crown gall disease in plants. Although these products are sometimes recommended for crown gall treatment, they are more effective when used as a preventative before the bacteria infects the plant.
Plants Affected by Crown Gall Over 600 different plants are affected by crown gall, including these common landscape plants: Fruit trees, particularly apples and members of the Prunus family, which includes cherries and plums Roses and members of the rose family Raspberries and blackberries Willow trees Wisteria
How to Fix Crown Gall
Unfortunately, the best course of action for plants affected by crown gall is to remove and destroy the infected plant. The bacteria can persist in the soil for two years after the plant is gone, so avoid planting any other susceptible plants in the area until the bacteria dies out for lack of a host plant. Prevention is an essential aspect of dealing with crown gall. Inspect plants carefully before you buy them, and reject any plants with swollen knots. The disease can enter the plant in the nursery through the graft union, so pay particular attention to this area.
To prevent the bacteria from entering the plant once you get it home, avoid wounds near the ground as much as possible. Use string trimmers with care and mow the lawn so that debris flies away from susceptible plants. Galltrol is a product that contains a bacterium that competes with Rhizobium radiobacter and prevents it from entering wounds. A chemical eradicant called Gallex may also help prevent the crown gall disease in plants. Although these products are sometimes recommended for crown gall treatment, they are more effective when used as a preventative before the bacteria infects the plant.
Plants Affected by Crown Gall Over 600 different plants are affected by crown gall, including these common landscape plants: Fruit trees, particularly apples and members of the Prunus family, which includes cherries and plums Roses and members of the rose family Raspberries and blackberries Willow trees Wisteria
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Dummer. ゛☀
2017年08月08日
While many people have both heard of and dealt with root rot in houseplants, most are not aware that this disease can also have an adverse effect on garden plants outdoors, including shrubs and trees. Learning more about the cause of root rot and how to look for early signs of root rot in garden plants will go a long way in its treatment. For root rot prevention and treatment info, keep reading. What is Root Rot? Root rot is a disease that attacks the roots of plants growing in wet soil. Since the disease spreads through the soil, the only root rot remedy for garden plants is often to remove and destroy the plant. However, you can try these corrective measures if you want to attempt to save a particularly valuable plant: Keep the soil as dry as possible. Don’t irrigate the plant unless the soil is almost completely dry. Pull back the soil to allow moisture to evaporate from the soil. The cause of root rot is a fungus. Species of the Pythium, Phytophthora, Rhizoctonia, or Fusarium fungi are the usual culprits. These fungi thrive in wet soil, and you can transfer them from one part of the garden to another when you transplant ailing plants.
When it comes to identifying root rot, look at the plants. Plants with root rot can’t absorb moisture and nourishment from the soil properly. The plants often resemble those suffering from drought and stress and mineral deficiencies. Signs of root rot in garden plants include stunting, wilting and discolored leaves. Foliage and shoots die back and the entire plant soon dies. If you pull up a plant with root rot, you will see that the roots are brown and soft instead of firm and white. Trees with root rot develop cankers, ooze reddish or black sap, and sometimes develop dark vertical streaks. Treatment for Root Rot The best root rot remedy for garden plants is prevention. Prevent root rot by filling in low parts of the garden and improving the soil with organic matter so that it drains freely. If you can’t improve the drainage, use raised beds where the where plant roots sit above the soil. Taking care not to overwater garden plants will also help. There are chemical fungicides and biological agents labeled as treatment for root rot disease; however, you should not use these products unless you know which fungus is causing the problem.
Once you know which fungus you are treating, your agricultural extension agent can recommend a product to treat that specific fungus. Fungicides are toxic chemicals that should be used with caution. Read the label and follow the instructions exactly. Store them in their original container and out of the reach of children. Even when all of the precautions are taken in the garden, root rot may still occasionally become an issue. However, if you pay attention to the signs of root rot in garden plants, you’ll have a better chance of saving your plants.
When it comes to identifying root rot, look at the plants. Plants with root rot can’t absorb moisture and nourishment from the soil properly. The plants often resemble those suffering from drought and stress and mineral deficiencies. Signs of root rot in garden plants include stunting, wilting and discolored leaves. Foliage and shoots die back and the entire plant soon dies. If you pull up a plant with root rot, you will see that the roots are brown and soft instead of firm and white. Trees with root rot develop cankers, ooze reddish or black sap, and sometimes develop dark vertical streaks. Treatment for Root Rot The best root rot remedy for garden plants is prevention. Prevent root rot by filling in low parts of the garden and improving the soil with organic matter so that it drains freely. If you can’t improve the drainage, use raised beds where the where plant roots sit above the soil. Taking care not to overwater garden plants will also help. There are chemical fungicides and biological agents labeled as treatment for root rot disease; however, you should not use these products unless you know which fungus is causing the problem.
Once you know which fungus you are treating, your agricultural extension agent can recommend a product to treat that specific fungus. Fungicides are toxic chemicals that should be used with caution. Read the label and follow the instructions exactly. Store them in their original container and out of the reach of children. Even when all of the precautions are taken in the garden, root rot may still occasionally become an issue. However, if you pay attention to the signs of root rot in garden plants, you’ll have a better chance of saving your plants.
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Dummer. ゛☀
2017年08月08日
Many ornamental and edible plants display dark, necrotic looking spots on their leaves. This is a symptom of bacterial leaf spot disease. Bacterial leaf spot on plants will discolor, and in extreme cases, kill leaves. Tiny, microscopic single celled organisms are what causes bacterial leaf spot. There are several methods on how to treat bacterial leaf spot and save your plant’s glorious leaves. Early identification is crucial to effective management of bacterial leaf spot disease. Symptoms of Bacterial Leaf Spot Bacterial leaf spot on plants may manifest in several different ways. Symptoms of bacterial leaf spot may include black edged lesions, brown spots with yellow halos or just light and dark areas on the foliage. Spots are irregular and measure between 3/16 and ½ inch wide. They can occur on the top or bottom of a leaf and kill sections of the tissue when they cluster together.
Symptoms of bacterial leaf spot may also appear on the edges of a leaf, where it appears brownish yellow and the tissue dries and breaks off. The leaves become quite papery and delicate when the bacterial disease attacks leaf edges. The disease is most prevalent on older leaves but will quickly establish on newer tissue. What Causes Bacterial Leaf Spot? Organisms that cannot be seen with the naked eye are the cause of this visibly damaging plant disease. Wet, cool conditions promote the formation of these bacteria, which can spread on plants quickly. The bacteria splash onto leaves or overwinter on plant debris in soil. Bacteria divide to reproduce and one bacterium can multiply quickly in just a matter of hours. Bacteria reproduce the fastest when temperatures are 77-86 F. (25-30 C.). High rates of infection will cause leaf loss and can seriously compromise a plants health. This makes the disease extremely contagious and bacterial leaf spot disease treatment extremely important.
The pathogen is also carried in infected seed; however, there are some disease resistant seed strains for food crops. Additionally, choose disease free transplants, rotate crops and avoid overhead watering to prevent spreading the bacteria. How to Treat Bacterial Leaf Spot In addition to the previous tips on preventing spread of the disease, you can use a copper fungicide on crops. This has limited management use unless it is applied early in the disease cycle. On ornamental plants, remove the affected leaves at the first sign to prevent the bacteria from jumping onto adjacent leaves. Some of the most common hosts are lettuce, beets, eggplant, peppers and large leaved ornamental plants, such as philodendrons.
Remove old vegetable debris in the garden and do not plant new crops where host plants were once growing. There are no recognized chemical treatments for bacterial leaf spot disease. Your best bet is prevention and mechanical control at the first sign of symptoms of bacterial leaf spot.
Symptoms of bacterial leaf spot may also appear on the edges of a leaf, where it appears brownish yellow and the tissue dries and breaks off. The leaves become quite papery and delicate when the bacterial disease attacks leaf edges. The disease is most prevalent on older leaves but will quickly establish on newer tissue. What Causes Bacterial Leaf Spot? Organisms that cannot be seen with the naked eye are the cause of this visibly damaging plant disease. Wet, cool conditions promote the formation of these bacteria, which can spread on plants quickly. The bacteria splash onto leaves or overwinter on plant debris in soil. Bacteria divide to reproduce and one bacterium can multiply quickly in just a matter of hours. Bacteria reproduce the fastest when temperatures are 77-86 F. (25-30 C.). High rates of infection will cause leaf loss and can seriously compromise a plants health. This makes the disease extremely contagious and bacterial leaf spot disease treatment extremely important.
The pathogen is also carried in infected seed; however, there are some disease resistant seed strains for food crops. Additionally, choose disease free transplants, rotate crops and avoid overhead watering to prevent spreading the bacteria. How to Treat Bacterial Leaf Spot In addition to the previous tips on preventing spread of the disease, you can use a copper fungicide on crops. This has limited management use unless it is applied early in the disease cycle. On ornamental plants, remove the affected leaves at the first sign to prevent the bacteria from jumping onto adjacent leaves. Some of the most common hosts are lettuce, beets, eggplant, peppers and large leaved ornamental plants, such as philodendrons.
Remove old vegetable debris in the garden and do not plant new crops where host plants were once growing. There are no recognized chemical treatments for bacterial leaf spot disease. Your best bet is prevention and mechanical control at the first sign of symptoms of bacterial leaf spot.
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Dummer. ゛☀
2017年08月08日
Tree cankers that ooze orange or amber-colored sap may indicate that the tree has Cytospora canker disease. The only way of fixing tree cankers caused by the disease is to prune out diseased branches. The best method of control is preventing damage that allows the airborne fungus to gain entry into the tree. Keep reading to learn more about what causes amber sap on trees and what can be done for a tree weeping amber color sap. What is Cytospora Canker? Cytospora cankers occur when the airborne cytospora fungus enters a tree through injuries and damage. 
It forms a sunken canker that spreads gradually, eventually girdling the branch and killing everything beyond the site of the canker. The diseased area may become covered with a growth of black fungus. What Causes Amber Sap on Trees? Cytospora canker is caused by the fungus Cytospora chrysosperma. The fungus enters the tree through damaged bark. The types of damage that leave the tree susceptible to infection include pruning wounds, flying debris from lawn mowers, string trimmer injuries, frost, fire and cat scratches. Tiny, bumpy fruiting bodies, called pycnidia, form on the dead tissue, giving the bark a rough texture. The pycnidia ooze an orange or amber, jelly-like sap that stains and discolors the bark. Symptoms are seen on a variety of fruit and shade trees throughout the United States.
How to Control Cankers There is no cure for cytospora canker on fruit trees and shade trees, but you can control the spread of the disease by pruning out the infected area. In late winter or early spring, remove infected branches at least 4 inches below the canker where the tree is weeping amber color sap. Disinfect pruners between cuts with a disinfectant spray or ten percent bleach solution.
If you use bleach on your pruners wash, rinse and dry them before putting them away to prevent corrosion. Proper tree maintenance that prevents stress goes a long way toward helping a tree resist disease and recover from cytospora canker. Water the tree slowly and deeply during dry periods. Fertilize annually in late winter or spring with a low-nitrogen, high-potassium fertilizer. Prune regularly so that you don’t have to make severe cuts later on. Remove dead, damaged and weak twigs and branches that may provide an entry point for disease and never leave stubs attached to trunks or large branches. Remember to disinfect your pruners. Avoid injuring trees when performing lawn maintenance. Raise the mower blades high enough so that they won’t nick exposed roots, and mow so that debris flies away from the tree rather than toward it. Use string trimmers with care to prevent cuts in the bark of the tree.
It forms a sunken canker that spreads gradually, eventually girdling the branch and killing everything beyond the site of the canker. The diseased area may become covered with a growth of black fungus. What Causes Amber Sap on Trees? Cytospora canker is caused by the fungus Cytospora chrysosperma. The fungus enters the tree through damaged bark. The types of damage that leave the tree susceptible to infection include pruning wounds, flying debris from lawn mowers, string trimmer injuries, frost, fire and cat scratches. Tiny, bumpy fruiting bodies, called pycnidia, form on the dead tissue, giving the bark a rough texture. The pycnidia ooze an orange or amber, jelly-like sap that stains and discolors the bark. Symptoms are seen on a variety of fruit and shade trees throughout the United States.
How to Control Cankers There is no cure for cytospora canker on fruit trees and shade trees, but you can control the spread of the disease by pruning out the infected area. In late winter or early spring, remove infected branches at least 4 inches below the canker where the tree is weeping amber color sap. Disinfect pruners between cuts with a disinfectant spray or ten percent bleach solution.
If you use bleach on your pruners wash, rinse and dry them before putting them away to prevent corrosion. Proper tree maintenance that prevents stress goes a long way toward helping a tree resist disease and recover from cytospora canker. Water the tree slowly and deeply during dry periods. Fertilize annually in late winter or spring with a low-nitrogen, high-potassium fertilizer. Prune regularly so that you don’t have to make severe cuts later on. Remove dead, damaged and weak twigs and branches that may provide an entry point for disease and never leave stubs attached to trunks or large branches. Remember to disinfect your pruners. Avoid injuring trees when performing lawn maintenance. Raise the mower blades high enough so that they won’t nick exposed roots, and mow so that debris flies away from the tree rather than toward it. Use string trimmers with care to prevent cuts in the bark of the tree.
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Dummer. ゛☀
2017年08月08日
It can be difficult to differentiate between leaf-related problems that occur in the summer garden, but angular leaf spot disease is pretty distinctive, making it easy for new gardeners to diagnose successfully. Plants that develop very regular leaf spots that follow veins may be suffering from this disease. Read on to find out more. What is Angular Leaf Spot? Angular leaf spot in plants is caused by several bacteria that survive in seeds and plant debris, including Pseudomonas syringae and Xanthomonas fragariae. These bacteria are somewhat host-specific, with P.
syringae targeting cucurbits and X. fragariae attacking strawberries. Symptoms first appear as small, water-soaked spots on leaves, but spread rapidly when conditions are moist and ambient temperatures are between 75 and 82 F. (24-28 C.). Spots expand until they fill the entire area between leaf veins, but do not cross over, which creates a tiled appearance on larger leaves. Older spots may dry out and tear, leaving holes behind. On fruits, angular leaf spot disease manifests as perfectly circular, water-soaked spots, much smaller than those on the leaves. As the disease progresses, the spots take on a chalky white appearance and may crack open, allowing pathogens to contaminate fruits and cause fruit rot.
How to Treat Angular Leaf Spot Treating angular leaf spot is not a simple, straightforward task. Once a plant is infected, it cannot be cured easily and most gardeners will remove the plant from their garden to prevent further spreading of the disease. Future problems can be prevented by only using certified, disease-free seed, practicing a three-year crop rotation with different plant families and making a habit out of cleaning up plant debris as it falls to the ground.
Beds with poor drainage or that are over-watered favor angular leaf spot — pay close attention to your watering habits if this disease has already developed in your plants. Before watering, check the soil moisture level with your hand. Unless the top 1 to 2 inches of soil feel dry to the touch, do not water; and when you do, make sure to water at the base of plants. Good watering practices can reduce the risk of many diseases, including angular leaf spots in plants.
syringae targeting cucurbits and X. fragariae attacking strawberries. Symptoms first appear as small, water-soaked spots on leaves, but spread rapidly when conditions are moist and ambient temperatures are between 75 and 82 F. (24-28 C.). Spots expand until they fill the entire area between leaf veins, but do not cross over, which creates a tiled appearance on larger leaves. Older spots may dry out and tear, leaving holes behind. On fruits, angular leaf spot disease manifests as perfectly circular, water-soaked spots, much smaller than those on the leaves. As the disease progresses, the spots take on a chalky white appearance and may crack open, allowing pathogens to contaminate fruits and cause fruit rot.
How to Treat Angular Leaf Spot Treating angular leaf spot is not a simple, straightforward task. Once a plant is infected, it cannot be cured easily and most gardeners will remove the plant from their garden to prevent further spreading of the disease. Future problems can be prevented by only using certified, disease-free seed, practicing a three-year crop rotation with different plant families and making a habit out of cleaning up plant debris as it falls to the ground.
Beds with poor drainage or that are over-watered favor angular leaf spot — pay close attention to your watering habits if this disease has already developed in your plants. Before watering, check the soil moisture level with your hand. Unless the top 1 to 2 inches of soil feel dry to the touch, do not water; and when you do, make sure to water at the base of plants. Good watering practices can reduce the risk of many diseases, including angular leaf spots in plants.
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Dummer. ゛☀
2017年08月08日
As gardeners, we face a lot of hurdles when it comes to keeping our plants alive and healthy. If the soil’s wrong, the pH is off, there are too many bugs (or not enough bugs), or disease sets in, we’ve got to know what to do and do it right away. Bacterial or fungal diseases can be devastating, but they usually give us a fighting chance. Viroids and viruses are another story altogether. Impatiens necrotic spot virus (INSV) is one of the most common viruses in the plant world. It’s an intimidating diagnosis for your plants, but without understanding the disease, you’ll never be able to manage it properly. What is INSV? INSV is an aggressive plant virus that can quickly infect greenhouses and gardens, and is especially common in impatiens plants.
It results in total losses, since plants affected by impatiens necrotic spot virus are no longer marketable, cannot be used for seed-saving and can continue to spread the virus as long as they’re present. Impatiens necrotic spot virus symptoms are highly variable, a fact that often delays gardeners’ decision making about infected plants. They may develop yellow bull’s eye markings, stem lesions, black ring spots and other leaf lesions, or infected plants may simply struggle to thrive. Once you suspect impatiens necrotic spot, treatment won’t help – you must destroy the plant immediately. If many plants are infected, it’s a good idea to contact your university extension office for testing to confirm the virus is present.
What Causes Impatiens Necrotic Spot? Western flower thrips are the primary vector for INSV in the garden and greenhouse. These tiny insects spend most of their lives on or near the flowers of your plants, though you may never see them directly. If you’ve noticed black spots or areas where pollen is spread across the flower, western flower thrips may be to blame. Placing yellow or blue sticky cards throughout potentially infected areas are the best way to confirm your suspicions of an infestation. Having flower thrips is annoying, but if none of your plants are infected with INSV, they can’t transmit the disease on their own. This is why it’s so important to quarantine any new plants that come into close contact with your old plants.
You should also clean your tools thoroughly between plants, especially if you are concerned about INSV. It can easily be transmitted via plant fluids, like those found in the stems and branches. Unfortunately, there’s no easy answer for INSV. Practicing good tool hygiene, keeping thrips under control and removing suspect plants are the best ways to protect yourself from the heartbreak this disease brings with it.
It results in total losses, since plants affected by impatiens necrotic spot virus are no longer marketable, cannot be used for seed-saving and can continue to spread the virus as long as they’re present. Impatiens necrotic spot virus symptoms are highly variable, a fact that often delays gardeners’ decision making about infected plants. They may develop yellow bull’s eye markings, stem lesions, black ring spots and other leaf lesions, or infected plants may simply struggle to thrive. Once you suspect impatiens necrotic spot, treatment won’t help – you must destroy the plant immediately. If many plants are infected, it’s a good idea to contact your university extension office for testing to confirm the virus is present.
What Causes Impatiens Necrotic Spot? Western flower thrips are the primary vector for INSV in the garden and greenhouse. These tiny insects spend most of their lives on or near the flowers of your plants, though you may never see them directly. If you’ve noticed black spots or areas where pollen is spread across the flower, western flower thrips may be to blame. Placing yellow or blue sticky cards throughout potentially infected areas are the best way to confirm your suspicions of an infestation. Having flower thrips is annoying, but if none of your plants are infected with INSV, they can’t transmit the disease on their own. This is why it’s so important to quarantine any new plants that come into close contact with your old plants.
You should also clean your tools thoroughly between plants, especially if you are concerned about INSV. It can easily be transmitted via plant fluids, like those found in the stems and branches. Unfortunately, there’s no easy answer for INSV. Practicing good tool hygiene, keeping thrips under control and removing suspect plants are the best ways to protect yourself from the heartbreak this disease brings with it.
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Dummer. ゛☀
2017年08月08日
Cercospora fruit spot is a common disease of citrus fruits but it also affects many other crops. What is cercospora? The disease is fungal and survives on any affected fruit in soil from the previous season. Read on to learn more. What is Cercospora? Fruit and crop management is an ongoing process. One of the key aspects is inspection of fruits and vegetables for disease and preventative measures early in the season to protect the crop. Cercospora leaf spot or fruit spot is a fungus that requires moisture and is wind borne. The disease survives in dormant lesions from previous season fruit.
Once warm, wet weather starts, the fungus disseminates condida, which are similar to a spore. These condida transfer from rain splash, mechanical transfer, or wind. The full name for this fungal disease is Pseudocercospora angolensis. Leaves of affected plants will produce circular spots with light brown to grayish centers. When the rainy season sets in, these spots become dark and almost black with a yellow halo. Leaves generally fall off after a period. Stem lesions are not frequent but you may find twig dieback. The fruit gets dark spots that may produce a tumor-like growth surrounded by a halo. These will sink in and develop necrosis. Early fruit that is immature will drop. Cercospora fungus in mature fruits will dry up and become tough. Symptoms are slightly different on various crops. Okra will develop a sooty mold on leaves and carrots get more necrotic spots on young leaves.
Roses will develop cercospora leaf spot as lesions and dark sunken areas on the leaves. Other crops affected are: Bean Beetroot Capsicum (peppers) Watercress Avocado Fig Coffee Cercospora Fungus Damage In well managed crops, it does not usually run rampant but the disease can produce unsavory fruit and diminish harvest. To preserve the best fruit, treatment of cercospora should start with cleanup of downed fruit at the end of the season and commence with fungicides applied in the spring. In small infestations, the few fruit affected will not limit crop yield much, but in heavily diseased plants, the entire crop may become useless. Not only are fruits unsightly and unappetizing, but they are not juicy or tasty. The necrotic areas from cercospora fruit spot are dry, tough, and woody in some species, creating a poor eating experience. These rather ugly fruits are impossible to sell and provide a dilemma as to disposal. In the compost pile, the fungus can survive unless temperatures are hot enough to destroy the condida. Fruit cleanup in affected areas is necessary to prevent the spread of cercospora leaf spot in the next season’s crop. Treatment of Cercospora In addition to cleaning up dropped fruit, it may be necessary to destroy heavily infected crops in fall. There are also fungal sprays and dusts recommended for control of cercospora.
Treatment must begin in the wet, rainy season when temperatures have warmed. It is advised to rotate the chemicals used yearly to minimize the chance of resistance. A second application may be required in wet, humid regions. Use all sprays and dusts in a manner consistent with the manufacturer’s instructions. If you are in doubt, use a licensed professional to apply the treatments.
Once warm, wet weather starts, the fungus disseminates condida, which are similar to a spore. These condida transfer from rain splash, mechanical transfer, or wind. The full name for this fungal disease is Pseudocercospora angolensis. Leaves of affected plants will produce circular spots with light brown to grayish centers. When the rainy season sets in, these spots become dark and almost black with a yellow halo. Leaves generally fall off after a period. Stem lesions are not frequent but you may find twig dieback. The fruit gets dark spots that may produce a tumor-like growth surrounded by a halo. These will sink in and develop necrosis. Early fruit that is immature will drop. Cercospora fungus in mature fruits will dry up and become tough. Symptoms are slightly different on various crops. Okra will develop a sooty mold on leaves and carrots get more necrotic spots on young leaves.
Roses will develop cercospora leaf spot as lesions and dark sunken areas on the leaves. Other crops affected are: Bean Beetroot Capsicum (peppers) Watercress Avocado Fig Coffee Cercospora Fungus Damage In well managed crops, it does not usually run rampant but the disease can produce unsavory fruit and diminish harvest. To preserve the best fruit, treatment of cercospora should start with cleanup of downed fruit at the end of the season and commence with fungicides applied in the spring. In small infestations, the few fruit affected will not limit crop yield much, but in heavily diseased plants, the entire crop may become useless. Not only are fruits unsightly and unappetizing, but they are not juicy or tasty. The necrotic areas from cercospora fruit spot are dry, tough, and woody in some species, creating a poor eating experience. These rather ugly fruits are impossible to sell and provide a dilemma as to disposal. In the compost pile, the fungus can survive unless temperatures are hot enough to destroy the condida. Fruit cleanup in affected areas is necessary to prevent the spread of cercospora leaf spot in the next season’s crop. Treatment of Cercospora In addition to cleaning up dropped fruit, it may be necessary to destroy heavily infected crops in fall. There are also fungal sprays and dusts recommended for control of cercospora.
Treatment must begin in the wet, rainy season when temperatures have warmed. It is advised to rotate the chemicals used yearly to minimize the chance of resistance. A second application may be required in wet, humid regions. Use all sprays and dusts in a manner consistent with the manufacturer’s instructions. If you are in doubt, use a licensed professional to apply the treatments.
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Dummer. ゛☀
2017年08月08日
By Mary H. Dyer, Master Naturalist and Master Gardener What is clubroot? This difficult disease is caused by a soilborne fungus that affects cruciferous vegetables like: Broccoli Cauliflower Cabbage Turnips Mustard Clubroot is particularly nasty because it can live in the soil for as long as seven to 10 years, making the area unfit for growing susceptible plants. Symptoms of Clubroot The primary symptoms of clubroot include enlarged, deformed, club-shaped roots and stunted growth. Eventually, the swollen roots turn black and develop a rotten aroma. In some cases, the disease may cause wilted, yellowing or purple foliage, although the disease isn’t always apparent above the ground.
Clubroot Control Clubroot is extremely difficult to manage and the best way to control its spread is to rotate crops, which means not planting cruciferous plants in the same area more than once every three or four years. Clubroot thrives in acidic soil, so raising the pH to at least 7.2 may be one of the most effective means of attaining clubroot control. Ohio State University Extension advises that calcitic lime is the best way to raise the pH, unless your soil is low in magnesium. In this case, dolomitic lime may be more effective. If possible, lime the soil at least six weeks before planting time. Be careful not to raise the pH too high, as highly alkaline soil may affect the growth of non-cruciferous plants. To prevent transmission of spores to uninfected areas, be sure to clean and disinfect garden tools and machinery after working in infected soil. Never invite trouble by moving infected plants or contaminated soil from one planting area to another (including the mud on the soles of your shoes).
Take necessary steps to prevent soil run-off during rainfall. According to Ohio State University, certain fungicides may help to reduce development of clubroot disease. Your local Cooperative Extension Office can offer advice for your specific situation. Otherwise, there are no chemicals approved for clubroot treatment. Care for Plants with Clubroot If your garden soil is affected with clubroot, the only recourse is to pull and discard plants as soon as possible, as aggressive action is the only way to discourage spread of the disease.
Dig around the plant and remove the entire root system to prevent the roots from breaking up and spreading the disease. Discard the plants properly and never put them on your compost pile. Next year, consider starting your own cruciferous plants from seed, using a sterile commercial potting soil. This is the best way to ensure you aren’t introducing the disease from an outside source. If you purchase seedlings, be sure to buy only plants that are guaranteed to be clubroot-free. Once again, be sure to rotate crops regularly.
Clubroot Control Clubroot is extremely difficult to manage and the best way to control its spread is to rotate crops, which means not planting cruciferous plants in the same area more than once every three or four years. Clubroot thrives in acidic soil, so raising the pH to at least 7.2 may be one of the most effective means of attaining clubroot control. Ohio State University Extension advises that calcitic lime is the best way to raise the pH, unless your soil is low in magnesium. In this case, dolomitic lime may be more effective. If possible, lime the soil at least six weeks before planting time. Be careful not to raise the pH too high, as highly alkaline soil may affect the growth of non-cruciferous plants. To prevent transmission of spores to uninfected areas, be sure to clean and disinfect garden tools and machinery after working in infected soil. Never invite trouble by moving infected plants or contaminated soil from one planting area to another (including the mud on the soles of your shoes).
Take necessary steps to prevent soil run-off during rainfall. According to Ohio State University, certain fungicides may help to reduce development of clubroot disease. Your local Cooperative Extension Office can offer advice for your specific situation. Otherwise, there are no chemicals approved for clubroot treatment. Care for Plants with Clubroot If your garden soil is affected with clubroot, the only recourse is to pull and discard plants as soon as possible, as aggressive action is the only way to discourage spread of the disease.
Dig around the plant and remove the entire root system to prevent the roots from breaking up and spreading the disease. Discard the plants properly and never put them on your compost pile. Next year, consider starting your own cruciferous plants from seed, using a sterile commercial potting soil. This is the best way to ensure you aren’t introducing the disease from an outside source. If you purchase seedlings, be sure to buy only plants that are guaranteed to be clubroot-free. Once again, be sure to rotate crops regularly.
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Dummer. ゛☀
2017年08月08日
Fusarium crown rot disease is a serious problem that can affect a wide range of plant species, both annual and perennial alike. It rots the roots and crown of a plant and can lead to wilting and discoloration on the stems and leaves. There is no chemical fusarium crown rot treatment, and it can cause stunted growth and even eventual death. There are steps you can take toward fusarium crown rot control, however, that include prevention, isolation and sanitation.
Keep reading to learn more about fusarium crown rot disease and fusarium crown rot treatment. Fusarium Crown Rot Control Many of the symptoms of fusarium crown rot disease take place, unfortunately, underground. There are, however, signs that affect the above-ground part of the plant, too. The leaves may become wilted and take on a yellowed, scorched appearance.
Also brown, dead lesions or streaks may appear on the lower part of the stem. Usually, by the time fusarium is visible above ground, its spread is pretty extensive below ground. It can also be seen in bulbs that are shriveled or rotten. Never plant these bulbs – they may be harboring the fusarium fungus and planting them could introduce it to otherwise healthy soil.
Treating Fusarium Rot in Plants Once fusarium is in the soil, it can live there for years. The best way to prevent it is to keep the soil well drained and to plant cultivars that are resistant to the disease. If it has already appeared, the best method of treating fusarium rot is removing and destroying affected plants. You can sterilize soil by moistening it and laying down clear plastic sheeting. Leave the sheeting in place for four to six weeks during the summer – the intensified heat of the sun should kill the fungus living in the soil. You can also leave an infected area unplanted for four years – without plants to grow on, the fungus will eventually die.
Keep reading to learn more about fusarium crown rot disease and fusarium crown rot treatment. Fusarium Crown Rot Control Many of the symptoms of fusarium crown rot disease take place, unfortunately, underground. There are, however, signs that affect the above-ground part of the plant, too. The leaves may become wilted and take on a yellowed, scorched appearance.
Also brown, dead lesions or streaks may appear on the lower part of the stem. Usually, by the time fusarium is visible above ground, its spread is pretty extensive below ground. It can also be seen in bulbs that are shriveled or rotten. Never plant these bulbs – they may be harboring the fusarium fungus and planting them could introduce it to otherwise healthy soil.
Treating Fusarium Rot in Plants Once fusarium is in the soil, it can live there for years. The best way to prevent it is to keep the soil well drained and to plant cultivars that are resistant to the disease. If it has already appeared, the best method of treating fusarium rot is removing and destroying affected plants. You can sterilize soil by moistening it and laying down clear plastic sheeting. Leave the sheeting in place for four to six weeks during the summer – the intensified heat of the sun should kill the fungus living in the soil. You can also leave an infected area unplanted for four years – without plants to grow on, the fungus will eventually die.
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