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Dummer. ゛☀
2017年08月08日
Dummer. ゛☀
New growth on your plants is a promise of blooms, big beautiful leaves or, at the very least, an extended lifespan; but when that new growth is wilting or dying, most gardeners panic, not knowing what to do. Although dying growth on plants of any age is a serious and difficult problem to manage, there are a few things you can try to save your plants before they go belly up. Why New Growth is Dying Well, that’s really the question, isn’t it? The reasons for tender growth dying are numerous, but they can generally be divided into these categories: bugs, vascular disease and root damage.
Pests – When you’re trying to determine how to fix dying growth, bugs are by far the easiest. Tip and twig borers, like those common on many evergreen trees and blueberries, prefer to burrow into the soft tissues at the end of shrubs and trees. Look for tiny holes at the end, or snap some dying tissue off and inspect it for galleries or tunnels. You may never see the tiny beetles responsible, but their telling tunnels and entry holes are evidence enough. Disease – Vascular diseases are caused by fungal and bacterial pathogens that invade the transport tissues of your plants. As these pathogens multiply, they clog the vascular tissues, making it difficult or impossible for some parts of your plant to get nutrients, water and send manufactured food back to the crown.
All this blockage will eventually cause the death of tissues, and tender new growth is usually the most susceptible since it’s the furthest from the roots. Root damage – Root damage is another common cause of dead new growth. Fertilizers are great and so is watering your plant, but there’s such a thing as too much. When this good stuff is in excess, it often leads to root damage. The smallest roots usually die first, but sometimes whole sections of the root system can be killed, especially in the case of excess slow-release fertilizer or fertilizer salt build-up. Fewer roots means fewer nutrients and less water that can be transported, so these valuable materials often doesn’t make it all the way to the tips of the plant once root damage is severe. How to Fix Dying Growth Dying growth can be difficult to cure, no matter the cause. If you’ve got boring beetles, they’ll probably be long gone before your plant starts to show signs of damage and vascular diseases are almost always death sentences, so intervention in either case is usually pointless. Damaged roots, on the other hand, can sometimes be regrown with careful management. If possible, dig your plant and check the roots.
You’ll need to prune out any that are black, brown or feel soft. Increase the drainage for outdoor plants by adding enough compost to fill the rootball’s hole one quarter to one half of the way. Potted plants will need to be flushed, do this by removing their saucers and watering the plant from the top, until the water runs out the bottom. Repeat this four times to remove excess fertilizer salts from the soil. If the soil stays soggy for more than a few minutes, you should consider repotting the plant. Going forward, pay close attention to how often you fertilize and water your plant. Remember, too much is just as bad for them as too little. Water only when the plant’s soil surface feels dry, and fertilize only when the plant appears to need it, such as when the leaves start to lighten in color. Never leave your plant in standing water, as this will only undo the work you’ve done to help save it.
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Dummer. ゛☀
2017年08月08日
Dummer. ゛☀
When black spores appear on your lawn or garden plants, it’s understandably frustrating -after all, you’ve given those plants lots of tender care and they’re sick despite your efforts. Try not to panic, we’ve got lots of information about treating black smut fungus, a common cause of black spores on turfgrass, small grains and ornamentals. What is Black Smut Fungus? Fungal diseases can be the most frustrating to deal with and they seem to spring up out of nowhere and disappear with the same level of mystery. Although black smut is a minor disease in most parts of the country, it’s important to know how to handle it when your lawn or garden suddenly develops a load of black spores.
Black smut is a fungal disease that appears on small grains, grasses, onions and even herbaceous ornamentals under the right conditions. Unlike many fungal diseases, though, plants affected by smut may live many years before they begin to show signs of the disease. Turf grasses, for example, often don’t look sick until three or four years after their initial infection. Although signs of smut will vary based on the species of smut and the host, common smut fungus symptoms include galls or boils that enlarge any above-ground plant tissues, yellow striping on leaves or a powdery brown or black material on plant parts. The black or brown powder is actually a fine covering of reproductive spores and will occur late in the disease process.
Smut Fungus Control Because smut spores are spread by wind and splashing water, it can be difficult to stop the problem at the source. Instead, treating black smut fungus has to focus on creating an unfriendly environment for the spores. When the outdoor temperatures rise above 60 degrees Fahrenheit (15 C.), it may seem like your smut problem is defeated, but it’s hard to kill the disease completely since the fungus resides in the growing points of the plant. On a lawn, an infection of smut can be tolerated provided that you’re overseeding with a more resistant grass species, such as the Kentucky bluegrass. Most importantly, you’ll have to carefully monitor your fertilization practices, as smut thrives in a high nitrogen environment.
Switch to a balanced fertilizer, such as a 10-10-10, and only apply it in the fall, after the smut pathogen is dormant. Keeping your plants healthy will help them resist a smut infection, but if the disease is very severe in valuable plants, you may consider applying a fungicide. Demethylase inhibitors are very effective when applied in the spring at the label rates. Remember, fungicides are always a last resort option, as most fungal issues can be corrected by modifying the environment.
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Dummer. ゛☀
2017年08月08日
Dummer. ゛☀
Growing grains and hay can be an interesting way to make a living or enhance your garden experience, but with great grains come great responsibilities. Ergot fungus is a serious pathogen that can infect your rye, wheat and other grasses and grains – learn how to identify this problem early in its lifecycle. What is Ergot Fungus? Ergot is a fungus that has lived side by side with mankind for hundreds of years. In fact, the first documented case of ergotism occurred in 857 AD in the Rhine Valley in Europe. Ergot fungus history is long and complicated. At one time, ergot fungus disease was a very serious problem among populations who lived off of grain products, especially rye. Today, we’ve tamed ergot commercially, but you may still encounter this fungal pathogen if you raise livestock or have decided to try your hand at a small stand of grain.
Although commonly known as ergot grain fungus, the disease is actually caused by the fungus in the genus Claviceps. It’s a very common problem for livestock owners and farmers alike, especially when springs are cool and wet. Early ergot fungus symptoms in grains and grasses are very hard to detect, but if you look at their flowering heads closely, you may notice an unusual shimmering or sheen caused by a sticky substance coming from infected flowers.
This honeydew contains a huge number of spores ready to spread. Often, insects inadvertently harvest and carry them from plant to plant as they travel through their day, but sometimes violent rain storms can splash the spores between closely spaced plants. Once the spores have taken hold, they replace viable grain kernels with elongated, purple to black sclerotia bodies that will protect new spores until the next season. Where is Ergot Fungus Found? Since ergot fungus has possibly been with us since the invention of agriculture, it’s hard to believe there’s any corner of the world untouched by this pathogen. That’s why it’s so important to know how to identify ergot when you’re growing any sort of grain or grass to maturity. The consumption of grasses or grains infected with ergot has serious consequences for man and beast alike.
In humans, ergot consumption can lead to a myriad of symptoms, from gangrene to hyperthermia, convulsions and mental illness. Because of the sensation of burning and the black gangrenous extremities in early victims, ergotism was once known as St. Anthony’s Fire or just Holy Fire. Historically, death was frequently the end game of this fungal pathogen, since the mycotoxins released by the fungus often destroyed human immunity against other diseases. Animals suffer many of the same symptoms as humans, including the gangrene, hyperthermia and convulsions; but when an animal has managed to partially adapt to ergot-infected feed, it can also interfere with normal reproduction. Grazing animals, particularly horses, may suffer from prolonged gestations, a lack of milk production and the early death of their offspring. The only treatment for ergotism in any population is to stop feeding it immediately and offer supportive therapy for symptoms.
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Dummer. ゛☀
2017年08月08日
Dummer. ゛☀
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.
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Dummer. ゛☀
2017年08月08日
Dummer. ゛☀
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.
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Dummer. ゛☀
2017年08月08日
Dummer. ゛☀
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.
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Dummer. ゛☀
2017年08月08日
Dummer. ゛☀
Choanenphora wet rot control is essential for those of us who love to grow squash, cucumbers and other cucurbits. What is Choaneephora fruit rot? You may not know the disease as Choaenephora, but you probably know what blossom end rot is. It is evidenced by soft, rotting ends on squash and other cucurbits. The disease is caused by fungal mold and it isn’t easy to get rid of once you have it, but it is easy to prevent. What is Choanephora Fruit Rot? Choanephora wet rot in plants begins in the flowers, which will bear a powdery white residue.
Once fruits begin to form and the flower withers away, the flower end of the fruit shows signs of mushiness and rot along with white or purplish powder. It progresses into the fruit, stunting growth and destroying much of the edible tissue. Once the disease is on your plants, it can spread quickly, so controlling Choanephora fruit rot immediately is essential to saving the crop. Choanephora fruit fungus can overwinter in garden debris. Fungal spores spread in spring by wind and insect movement. Warm, wet conditions encourage the growth of the fungus, which is one of the fastest growing fungal diseases. You can use a hand magnifier and see whisker-like growth on the fruit to differentiate it from another common fungal disease, Rhizopus soft rot. In areas with high humidity and moist conditions, the fungus can blight as much as 90 percent of a crop. Choanephora wet rot in plants is difficult to control because new flowers are forming daily and are newly susceptible to the spores. Choanephora Fruit Rot Treatment There is no prescribed Choanephora fruit rot treatment. Some growers suggest using fungicides, but these are only affective on the flowers that are treated. Over the course of a day or two, these flowers are replaced by new ones so you would be faced with treating the plant every couple of days. This is not a safe solution for developing fruits, so fungicides are, therefore, not considered useful. Some gardeners swear by the addition of calcium to soil to prevent the disease by adding Epsom salts or crushed eggshells to the soil at planting. This will certainly bolster the health of the plant but will not prevent spores from eating into the fruit.
Choanephora wet rot control actually begins when you are planning the vegetable garden. Before you plant a single seed, consider crop rotation. This will prevent any cucurbits from being planted in the same soil as the previous year where soil may be contaminated by the fungus. Space the plants well so there is plenty of air circulation to dry out the leaves and stems. Avoid irrigating overhead in the evening when plants cannot have time to dry off. Planting squash and other susceptible plants in raised beds with drip irrigation also seems to be helpful. Clean up infected plant debris. You may still get one or two infected fruits, but you should be able to save the bulk of the crop with these practices.
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Dummer. ゛☀
2017年08月08日
Dummer. ゛☀
If your raspberry bush buds die, the side shoots wilt and the canes fail, cane blight is probably the culprit. What is cane blight? It’s a disease that attacks all kinds of cane plants including black, purple and red raspberries. You’ll do best to start a defense against cane blight early by adopting good cultural practices. Read on for information about plants affected by cane blight and cane blight control.
What is Cane Blight? Cane blight is a disease that affects brambles. It is usually caused by the fungus Leptosphaeria coniothyrium, a fungus that can also attack roses and rot the fruit of apple and pear trees. The fungus can live all winter long on dead canes. Spores formed on these canes cause infection when rain, wind or insects carries them into damaged areas or wounds on the canes. A bacterial form of cane blight also exists. Bacterial cane blight is caused by an undetermined pathovar of the bacterium Pseudomonas syringae. Plants Affected by Cane Blight All bramble plants – that is, all Rubrus species – can be affected by cane blight. Perhaps the species most susceptible is black raspberry, but all raspberries can get it, as can roses. No cane-blight-resistant raspberry cultivars have been identified yet. In the meanwhile, choose less susceptible cultivars.
Cane Blight Symptoms You are most likely to see cane blight infections between late April and early May. Look for bud failure, lateral shoot wilt, and cane death. You are likely to first notice wilted foliage. Look carefully below this foliage for dark brown or purple cankers that can extend along the cane for several inches. Bacterial cane blight symptoms are similar to those of the fungus-caused disease. Red-brown discolorations appear on stems, then turn dark purple or black and necrotic. Cane Blight Control Control of cane blight is possible through both cultural and chemical means. Cultural You can help prevent fungal cane blight by using cultural practices that prevent damage to the canes. These include eliminating weed-whacking near the canes, controlling insect pests and limiting pruning. It also helps to try to keep the cane foliage dry, or aid its rapid drying.
For example, keeping fruiting rows narrow and weeded assists them in drying after a rain, as does thinning out weak canes. Also, you should take care with the cane site selection. You want the canes to have good drainage and air circulation. It’s also a good idea to dispose of old, diseased canes immediately after harvest. That prevents overwintering fungus. Chemical If the cane blight disease is getting the best of your brambles, apply an application of lime sulfur or copper to your dormant plants. Use liquid lime sulfur when new leaves arrive, and be sure to cover all of the canes thoroughly.
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Dummer. ゛☀
2017年08月08日
Dummer. ゛☀
Diagnosing plant ailments is crucial to plant management and health. Cenangium canker of trees is one of the more insidious diseases. What is Cenangium canker? Read on for tips on recognizing, treating and managing sooty bark canker. What is Cenangium Canker? Pine, spruce and fir trees provide much needed shade, animal food and cover, and enhance the landscape with their architectural elegance. Unfortunately, these species are prone to fungal diseases such as sooty bark canker, or Cenangium. Over time, the disease can girdle your trees, reducing nutrients and water to the upper growth and preventing the flow of plant starches that feed development.
Trees can die without proper treatment. Cenangium is a fungal disease that produces a slow growing canker that affects the above mentioned evergreens as well as aspens. It is the most widespread canker on trees in the West. Infection begins in July through September when spores germinate and land on damaged or cut parts of the tree. Once the spores have taken root, they fruit and spread anew. Damage is seen as small oval, dead areas of bark. Over time, it can kill entire branches and in a bad year, spread to all parts of the tree. Fortunately, Cenangium canker of trees is extremely slow growing and tree death rarely results unless it is repeatedly attacked over several seasons and also experiences stresses such as low water and other disease or pest issues. Managing Sooty Bark Canker Sadly, there is no effective Cenangium canker treatment. This means early recognition is essential to managing sooty bark canker.
In addition to dead areas of the bark, the needles will begin to brown and die or leaves will wither and fall off. Each year’s growth of the fungus will produce light and dark areas, “zebra”-like girdling of the stems. As the outer bark is eaten away, the interior bark is exposed as powdery and black. Over time, the canker girdles the stem or branch and it will completely die. In nature, this has a somewhat beneficial effect, helping trees get rid of old limbs. Fruiting bodies are 1/8 inch wide, cup-shaped and gray and granular. Since there is no effective Cenangium canker treatment, management of the disease is the only option. The only line of defense is recognizing the symptoms early and taking steps to remove infected plant material. The spores can persist, so it is not recommended to compost the material but rather bag it and send it to the landfill or burn it.
Use good pruning techniques when removing diseased limbs. Do not cut into the branch collar and use sterile tools to prevent spreading the spores. Remove infected limbs as soon as possible before fruiting bodies shoot ripe ascospores into the air in moist conditions. Ascospores are the next generation of the fungus and will rapidly spread in ideal weather climates.
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Dummer. ゛☀
2017年08月08日
Dummer. ゛☀
Cytospora canker disease generally attacks spruces, especially Colorado blue and Norway varieties, as well as peach trees, Douglas firs or hemlock trees. What is cytospora canker? It is a destructive disease caused by the fungus Leucostoma kunzei that disfigures and can even kill vulnerable trees. Read on for more information about symptoms of cytospora canker as well as cytospora canker treatment.
What is Cytospora Canker? You may not have heard of cytospora canker until after a tree in your backyard is infected. If you notice that the lower limbs on your tree are dying, the tree might have cytospora canker disease. It attacks older trees, stressed trees and those with shallow roots or planted in inappropriate sites. One of the first symptoms of cytospora canker disease on spruce is the browning of needles on the tree’s lower limbs. When they fall, you may notice light patches of resin on the dead bark of the branches.
Over several years, symptoms of cytospora canker spread and upper branches brown and die. Dead areas of bark appear, known as cankers. On trees without needles, like peach trees, look for cankers on branches around pruning wounds. They may be present for several years, extending along the branch, before they kill it. Control of Cytospora Canker You may look to fungicidal sprays as a cytospora canker treatment, but these are not effective and are not recommended by experts. Instead, try using organic methods for control of cytospora canker. Prevention is easier than cytospora canker treatment. Take care not to wound trees susceptible to this disease. Wounds, like those from weed whackers and saws, serve as entry points for the fungus. Crowded trees are more likely to get and pass along the fungus. Plant yours with lots of room and good air circulation.
Take every precaution to keep the trees healthy and strong. Water them during dry periods and fertilize them annually to provide nutrients. Vigorous trees are less likely to get attacked. Prune out any infected branches and burn them, since the fungus overwinters in cankered bark. Use bleach to disinfect the pruners before and after each use. The best time for pruning is late winter or early spring in dry, sunny weather.
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