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Dummer. ゛☀
2017年09月13日
Dummer. ゛☀
"Dog vomit fungus" is one of those oddities of nature that just makes you say "eww eww." Even if you've never had it in your garden before, it's pretty safe to say that you'll know it when you have it; its nickname couldn't be more precise.
The fungus, which has the scientific name Fuligo septicai, is also sometimes called "scrambled egg fungus." It is most likely to show up during warm, wet periods, sometimes seeming to pop up out of nowhere overnight. It often grows in wood mulches or along the sides of untreated wood, and sometimes in lawn grass.
Their less-than-attractive appearance may cause concern that they're harming garden plants, but they are actually really interesting (if you have kids, they'll get a kick out of learning more about this disgusting fungus.) Slime molds, such as Fuligo septicai, are saprophytic, which means that they feed on decaying organic materials. They are not diseases, and won't really harm your plants. Occasionally, they'll grow on plants that are growing in mulch, and if a large enough colony forms, they may smother the plant. This is uncommon, however, and you'll usually just find the mold in the mulch itself. Dog vomit fungus, like other slime molds, are most often found in moist, shady areas, where they thrive. Crevices, mulch, rotting logs, leaf litter and along untreated lumber are all very common places to find it.
Description of Dog Vomit Fungus Its name is fairly accurate. If you've had a dog, you'll know it when you see it. It is also known as "scrambled egg fungus," because the fruiting bodies (the part you see) is light yellowish in color and looks a bit like scrambled egg curds. It usually appears in small clumps, clinging to mulch, the bases of rotting tree trunks, or other wooden objects.
Life Cycle of Dog Mold Fungus Slime molds like the dog mold fungus produce spores that are wind-borne. They are very resistant and can survive even during hot, dry weather. The spores can remain viable for several years, waiting for conditions to be right. When warm, moist conditions are present, those dormant spores absorb moisture and crack open to release a swarm sphere, and shortly after, gardeners will see that tell-tale, disgusting looking fungus appear.
Controlling Dog Vomit Fungus As mentioned above, generally dog vomit fungus poses no threat to plants. It's really just an unattractive nuisance. The best way to control it is to break it up and dry it out. Dog vomit fungus growing in mulch or leaf litter can simply be raked out and disposed of (probably not in your compost, unless you either practice hot composting or want more of it to show up in your garden later.) Dog vomit fungus growing along lumber or tree stumps can be scraped away with a trowel or small shovel and disposed of. If you have it growing in your lawn or in plants, gently rake it out as best you can and get rid of it. A strong jet of water will also dislodge any of the remaining fungi still clinging to the plants (though it may pop up again later.)
If dog vomit fungus continues to be a problem, you may want to consider switching from wood-based mulches to something else, such as gravel. In general, it doesn't pop up often enough to be a real issue. So, if you see this unattractive fungus in your garden, don't panic. Its primary crime is being unpleasant to look at. Leave it (if it doesn't bother you too much), or scrape it up and get rid of it, and hope for drier conditions in the future so you won't have to see it again anytime soon.
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Dummer. ゛☀
2017年09月13日
Dummer. ゛☀
Does Milk Control Powdery Mildew? You can do everything right in your garden and there will still be problems - like powdery mildew. Some things are beyond our control. When weather conditions are right, a host of fungal diseases will move in. Keeping your plants healthy and giving them plenty of air circulation will help them withstand many problems, but not all. Sometimes you need the help of a fungicide.
However, that does not necessarily mean you need to use chemicals. What is Powdery Mildew? Powdery mildew refers to a group of diseases that all show up as a powdery white coating on leaves, stems, and sometimes even flowers. It does not usually kill plants, but it can weaken them and diminish photosynthesis, leading to poor yield and plants that don't last the season. It is spread by spores that are carried by the wind or splashed onto leaves. Powdery mildew favors humid, rather than wet conditions. The spores form when the humidity is high and disperse when the humidity diminishes. Spores can over-winter on plants or plant debris and start the process all over again. End of season garden clean-up and planting disease resistant varieties are your best powdery mildew controls.
Although powdery mildew affects many plants, there are several species of powdery mildew fungus and they each have their preferred hosts. So powdery mildew on zinnias will not move to lilacs or cucumbers. No matter what plant has powdery mildew, this is a fast spreading problem and you need to take action quickly. However you don't need to reach for the big guns. There are a handful of relatively low toxic remedies and most can be homemade.
A baking soda solution is one and the following milk solution is another. Using Milk as a Fungicide Milk has become the latest secret weapon in fighting powdery mildew. Actually it's not so secret and it's been used in treating diseases for decades. It's been tried as an additive to improve the spreading and sticking of other pesticides and Dr. Linda Chalker-Scott, of Washington State University, cites many studies where milk was tested against the transmission of tobacco mosaic and other viruses. - to mixed reviews. Most recently, milk has been getting a lot of good press as an anti-fungal spray, specifically against powdery mildew on cucumbers and squash.
How to Use Milk to Control Powdery Mildew The dilution used by home gardeners is: 1 part milk to 2 - 3 parts water. The solution is then sprayed on the plant's leaves every 10-14 days. It works best as a preventative, rather than a cure, which makes it hard to determine whether it actually works since you don't know if your plants would have gotten it anyway.
How does Milk Work as a Fungicide? For the past several years, researchers have been experimenting with spraying a diluted solution of regular milk on a variety of plants, mostly cucurbits (squash and cucumbers). They have been seeing enough success to continue experimenting. Home gardeners are now getting in on the research, but very often a control group is missing, so their results are not definitive.
As to exactly how milk works against the fungus, no one is certain. It appears that the proteins in milk offer an antiseptic-like effect, when exposed to sunlight. To be effective, the solution should be applied in bright sun. Soak both sides of the leaves until the solution is dripping. If you've ever left milk out in heat or direct sun, you know that the odor of spoiled milk is not pleasant, but it does dissipate somewhat quickly. The protein is in the milk fat, and both whole and skim milk have been tried by home gardeners. In fact, researchers used whey, a milk by-product, because it was cheaper.
You can try your own experiments with whatever you have on hand. To really test it, spray the solution on only some plants and leave others untreated. Author and horticulture professor Dr. Jeff Gillman has also recommended using the milk solution for black spot on roses. There hasn't been a lot of institutional research on this, but home remedies are not profitable and often get short shrift in research. Interestingly, Dr. Gillman also recommends simply spraying plants prone to mildew with water. Since powdery mildew doesn't like getting wet, spraying the plants daily seems to help thwart it.
Sources: Clemson University Extension Jeff Gillman Jeff Gillman on Gotta Garden Science News The Myth of Milk and Roses, Linda Chalker-Scott, Ph.D.
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Dummer. ゛☀
2017年09月13日
Dummer. ゛☀
What is Powdery Mildew? Powdery mildew is one of the most commonly occurring plants problems. It is a fungal disease that affects plant leaves and stems, coating them in what looks like a white or gray powder-like substance. Although any plant can get powdery mildew, some are very susceptible, crab apples, cucumbers and all types of squash, lilacs, phlox and roses. In severe cases, powdery mildew can even spread to the buds, flowers, and fruits of plants. The white coating greatly diminishes the appearance of the plant, but it is not fatal unless left uncontrolled. However, as it spreads, it stresses and weakens the plant and makes it hard for photosynthesis to occur. It's wise to treat it as soon as you see symptoms, or maybe even before.
Controlling Powdery Mildew with Baking Soda Baking soda has long been used as an inexpensive control for powdery mildew on plants. Unfortunately baking soda fungicide is mostly effective as a preventative, offering only minimal benefits after your plants have become infected. If you know which plants are susceptible, spraying them weekly with the baking soda recipes, during humid or damp weather, can greatly reduce the incidence of powdery mildew in your garden.
To control powdery mildew on plants, mix together: 1 tablespoon of baking soda ½ teaspoon of liquid soap 1 gallon of water Do not store unused mixture.
While this recipe has been known to be effective, it can burn the leaves of some plants. It is recommended that you water your infected plants well a couple of days before applying this mixture, and don’t apply it in full sun. Try on a small area first, to test the plant’s response before spraying the entire plant. Some recipes also recommend applying 1 tablespoon of ultralight horticultural oil to the mixture. The oil coats and smothers the fungi. The soap is added to help the mix spread and cling to the leaf surface. Be sure to apply to lower leaf surfaces as well.
Control versus Cure Unfortunately, this baking soda mixture works best as a preventative, applied before powdery mildew has a chance to spread on your plant. It is less effective as a cure, once the fungus has taken hold. If you know a plant is affected by powdery mildew year after year, as is the case with many monarda, pholx, and lilacs, they spraying early in the season may prevent any occurrence of powdery mildew that year. It is still worth trying after signs of powdery mildew appear, but it might not get rid of all the fungus.
Another Homemade Powdery Mildew Option Spraying plants with a milk mixture, after they have been infected with powdery mildew, is showing a lot of promise for actually killing the fungus. Read more about how to use milk to control powdery mildew.
There May be More Uses for This Baking Soda Recipe Researchers are still studying the effects of using a baking soda mixture on other fungal diseases such as: black spot, rust and anthracnose.
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Dummer. ゛☀
2017年09月13日
Dummer. ゛☀
Why does magnolia foliage get black spots on it? Have you ever had the leaves on such a tree turn brown and then fall off? Then you will find the following exchange between the author and a reader interesting -- and, hopefully, helpful. The reader reported buying two magnolia trees and bringing them home, only to discover that the leaves had black spots all over them. So he returned to the garden center, scrutinized the rest of the crop, and learned that all of the other magnolias that this business had for sale displayed the same black spots.
When confronted, their response was: Moisture is to blame. Back home, the leaves eventually turned brown and fell off. The reader wondered, "What type of disease is this?" Here was the response to the reader; this information may be able to help many of you out there who have similar problems: Since Leaf Spot Is a Fungus, It Thrives in Moist Conditions Your problem sounds like a case of leaf spot. Since it is usually caused by a fungus, "moisture" (which was cited as the culprit at the store) is, indeed, likely to blame. Fungi thrive in moist conditions. As the University of Connecticut (UConn) Extension remarks, in the presence of the fungal spores, all it takes is "a film of water" on the leaf for the spores to germinate and penetrate the leaf. It is at that point that foliage becomes diseased.
The actual spots of "leaf spot" are not always black, by the way. They are commonly brown, as well. But do not assume that, just because the color of the spot is not dark, the disease is not leaf spot: The color can be tan, too or even red. Most experts do not regard leaf spot as something to worry over very much when it occurs on a mature specimen in this genus, be it a star magnolia tree, saucer magnolia, etc. Their advice typically is to remove the diseased brown leaves that have dropped and then dispose of them properly. The idea is to prevent the fungus from spreading.
But, as the UConn Extension also notes, leaf spot can be a serious disease for trees under stress, which includes newly-planted trees (as in your case). Already weakened by the stress, young magnolia trees infested with leaf spot can die from the infestation. It is in these situations that chemical control is warranted. Seek a copper-based fungicide to battle the leaf spot. Problem is, as the same source observes, you have to spray the fungicide on at the right time in order for it to do its job. When is the right time? Well, you must understand that the fungicide works as a protectant, not as a cure. This means, unhappily, that the right application time is before the fungus attacks a leaf.
Do you see the challenge implicit in this treatment? You must be vigilant enough to detect the leaf spot when it first attacks your magnolia tree. If you catch it and spray before too much foliage has been infected, you may be able to halt its advance. Otherwise, treatment is unlikely to be effective. Preventive Control Measures You Can Take In terms of prevention (for future reference), healthy magnolia trees tend to resist leaf spot.
So care for your magnolia properly to keep your specimen in tip-top condition and, thereby, more resistant to this disease. Since moisture promotes the spread of fungus, it is a good idea to enhance air circulation. This can be achieved by: Pruning off branches on the magnolia trees that are rubbing against each other. Pruning off branches of any surrounding trees or shrubs that may be invading the magnolias' space.
The Fungi (and One Bacterium) That May Be the Culprits Above, it was noted that the leaf-spot disease is caused by fungi. But precisely which fungi? And can anything else cause it? According to the Pacific Northwest Plant Disease Management Handbook, a bacterium can also be the culprit: namely, Pseudomonas syringae pv. syringae. The same source lists the following as the main fungi responsible for the problem: Cladosporium spp. Coniothyrium spp. Phyllosticta magnoliae Septoria spp.
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Dummer. ゛☀
2017年09月13日
Dummer. ゛☀
Powdery mildew is a fungal disease that results in a powdery gray or white coating on the leaves and stems of infected plants. Several different species of fungi in the order Erysiphales can cause the disease, though the symptoms are always similar. A powdery mildew infection generally starts out as a few spores on the leaves but quickly spreads. The white powdery surface is a thick coating of the fungi spores.
The fungi easily overwinters in garden debris, and thus is very hard to eradicate entirely. It can eventually cause yellowing the leaves and premature leaf drop.
As virtually all gardeners know, powdery mildew thrives in humid conditions with moderate temperatures. In any region with humid summers, powdery mildew virtually always makes its appearance. While it can affect any plants, there are certain species much more susceptible to heavy infection: Some Plants Susceptible to Powdery Mildew: Apples Begonia California poppy Dahlia Delphinium Hollyhock Hydrangea Lilacs Monarda Oak Strawberries Phlox Roses Strawberries Zinnia Damage to Plants
In many cases, powdery mildew does little damage to plants but is merely unattractive. And some plants seem so susceptible to powdery mildew that it is virtually unavoidable--an expected cost if you choose to grow these species. Many gardeners simply resign themselves to the fact that powdery mildew will make an appearance nearly every year and don't bother to fight it aggressively. But besides being unattractive, powdery mildew can in extreme cases result in leaf yellowing and dropping, stunted plant growth, distortion of buds, blooms, and fruit, and eventual overall weakening of the plant.
Disease Life Cycle Spores overwinter on diseased plant parts and begin asexual production of new spores once the weather warms. New spores are carried on the wind to other parts of the plant or to other nearby plants. Spores never stop producing more spores, so if infected leaves are not destroyed, the problem can never be eradicated and will only get worse.
Treatment and Prevention Powdery mildew thrives in temperatures between 60° and 80°F. Dry, shady conditions are ideal, as are areas with poor air circulation. Few chemical fungicides offer much cure for powdery mildew; the best strategies are more mechanical in nature, such as simply removing and destroying diseased plants and plant parts. Planting disease-resistant cultivars and making sure you allow for good air flow are two ways to guard against powdery mildew. Beyond this, possible control methods to keep powdery mildew in check include the following: Plant species that are most susceptible in a location where they can receive early morning sun. This will allow condensation to dry out quickly and reduce the humid conditions that foster the fungus.
Enhance air circulation by spacing plants well apart. Better ventilation will reduce the disease. Dense plants can be thinned out to improve air flow. Inspect plants regularly during warm, dry conditions, and remove any leaves that show signs of infection. Destroy (do not compost!) infected plant parts. A spray made with baking soda, if applied weekly at the first signs of infection, can protect plants against further damage. Plants that are badly infected should be ripped out and destroyed to prevent the disease from spreading further.
A commercially available organic option is Neem oil, which both treats existing powdery mildew and protects the plant against further infection. Interestingly enough, an effective measure in preventing and treating powdery mildew is to spray the foliage of your plants daily with plain water from the hose. Powdery mildew hates water! The only caveat with this method is to be sure you do it early in the day so that the foliage completely dries before cooler evening temperatures arrive, otherwise you may invite other fungal diseases such as black ​spotinto your garden.
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Dummer. ゛☀
2017年09月13日
Dummer. ゛☀
Diagnosing the Problem Phalaenopsis and other orchids respond quickly to anything amiss in their environment. Black spots are one of the trouble signs. The first step in treating the dark spots on your orchid's leaves is diagnosing the problem. Some phalaenopsis have naturally mottled leaves, so it may be natural coloration. However, leaf spotting can also signify a bacterial or fungal disease. Bacterial leaf spot is fairly common among orchids, and it can be aggressive and dangerous on phalaenopsis.
Similarly, fungal disorders and cause leaf spots, especially if the plant is left exposed to moisture on chilly nights. Unless the plant is valuable, the best approach is to discard it, as the disease is highly contagious and will spread from plant to plant from splashing water.
Black Rot A danger to orchids any time the weather is rainy or damp for extended periods, black rot can quickly destroy an entire plant if left unchecked. Caused by one or both of the fungi Pythium ultimum and Phytophthora cactorum, black rot affects a wide variety of orchids. A Fungal Infection The fungi that cause black rot in orchids consist of spores capable of independent movement, called zoospores, which swim through the water. If that water happens to be sitting on an orchid leaf, the zoospores can penetrate the plant tissue and begin the next stage in their life cycle. Once this occurs, the visible signs of infection - small, watery, translucent spots - expand quickly and change to brown and then black. Left untreated, the affected plant or plants may infect others and will probably die themselves.
Symptoms As it name implies, black rot shows up as dark blackish spots or lesions on the affected plant part. The black spot or spots enlarge rapidly and can spread throughout the plant. If allowed to reach the crown of a monopodial (single-stemmed) orchid, the rot will kill the plant. Affected leaves may turn yellow around the infected area, and the lesions themselves will be soft and exude water when pressure is applied. Prevention.
Unsterilized pots, media or water sources, as well as water splashed from affected plants nearby, are all excellent means of spreading the fungus. If your orchids are outside, keep them 3 to 4 feet above the ground to avoid splash contamination. Whether outside or inside, do not allow your orchids' leaves to remain wet for any extended periods. Good air circulation in the growing area is key. At first signs of infection, segregate all affected plants to avoid contaminating healthy plants. Finally, some growers recommend the use of a high-calcium fertilizer in the spring to help avoid black rot in new growth.
Cut Out the Rot To stop the spread of black rot in your orchid, begin with a sterile knife and cut out the diseased portion of the plant. Remove the infected portion of the leaf, or the entire leaf if necessary, to halt the spread of the fungus before it reaches the crown. Place the plant in an area that receives good air circulation to allow the cut to dry.
Use a Fungicide Once the infected plant parts have been removed, a fungicide should be applied to protect the remaining healthy tissue. Cinnamon is an excellent fungicide, and ground cinnamon may be applied straight from the spice jar directly to the exposed area where infected portions of the plant have been excised. First Rays Orchids also recommends mixing cinnamon with either casein-based glue (such as Elmer's) or cooking oil to form a thick paste. This paste is fairly waterproof and can be used to cover the wound.
Drenching the affected plant with a fungicide is also an option. Drenches of a protectant fungicide such as Truban or Terrazole are recommended if the disease is diagnosed early. For more advanced cases, a systemic fungicide such as Aliette or Subdue is more effective. Captan, Dithane M-45, BanRot, Subdue and Physan 20 have also been recommended by some growers for control of black rot.
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Dummer. ゛☀
2017年09月13日
Dummer. ゛☀
Roses have a reputation for getting all kinds of diseases. While modern roses are a lot less prone to problems than the tea roses favored not so long ago, there will inevitably be seasonal rose problems to deal with. Most rose diseases are caused by damp or humid weather. While you can't do anything to control the weather, you can give your rose bushes good air circulation, so they are able to dry off as best they can.
This will help avoid rose diseases to some degree, but not entirely. You will also need to keep tabs on your rose bushes so that you can remedy any bad situation before it gets out of hand. Be sure to accurately identify the problem before reaching for a spray and start with the least toxic solution. You can read more about organic controls in An Overview of Some Common Organic Garden Pesticides.
The Big 4 of Rose Diseases Black Spot: Black spot is a fungus that is very common during humid weather because it is a water-bourne disease. As its name implies, small black spots form on leaves and stems, eventually causing the leaves to drop and weakening the plant. Treatment: Choose black spot resistant varieties and be meticulous about sanitation. Water the roots of the rose, avoiding the foliage. Water in the morning, so that splashed leaves have time to dry off. If Black Spot is an annual problem, try a dormant spray of lime sulfur at the end of the season and again in early summer. Once Black Spot appears, it is hard to stop. Neem oil and Sprays containing Potassium bicarbonate are somewhat effective.
Downy Mildew: Downy mildew is a very serious disease that spreads rapidly and can defoliate a rose plant in days. It is not as common as Black Spot and favors cool, wet weather. Purple spots with yellow edges form , often on the veins on the top side of the leaves and along the stems. Pale gray fuzz can form on the under side of the leaves. The leaves will eventually become brittle and fall. Treatment: The good news is that Downy Mildew often clears up with the weather. To reduce the chance of Downy Mildew, practice good garden sanitation and keep the rose plants well pruned for air circulation. As with other diseases, a dormant spray may help.
Rust: A Rust infection is easy to spot. Small orange pustules spots form on the undersides of the leaves. This fungus can also cause defoliation. Rust is most prevalent when nights are cool. Treatment: Treatment of Rust is similar to treatment of Black Spot, above: Good sanitation and a preventative dormant spray after pruning. Once infected, remove all infected leaves and try Neem oil for control.
Mosaic Virus: Once a rose is infected with Rose Mosaic Virus, there’s not much to be done except check with the nursery for a replacement. Rose Mosaic Virus shows up as yellow mottling on leaves and deformed new growth. It can stunt growth or it can be a mild infection. If there are only a few affected leaves, the plant may continue growing and blooming fine. The really good news is that it won’t spread to your other roses. Read Rose Growing Problems - Prevent Rose Problems Before They Occur, for advice on avoiding these diseases and other problems.
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Dummer. ゛☀
2017年09月13日
Dummer. ゛☀
Description Black spot is basically what it sounds like: roundish black spots on leaf surfaces. The spots grow over time, and the foliage around the spot yellows. Eventually, the entire leaf falls off.
Damage to Plants The issue with black spot is that the defoliation that occurs when the fungus is allowed to get out of control weakens the plant. And not just for the current growing season, but for the next season as well. The main function of plant foliage is to absorb energy from the sun and perform photosynthesis. If your plant loses all or most of its leaves to black spot, it will be unable to collect and store energy for the winter, as well as for the burst of growth that occurs in spring. You'll see weaker growth and reduced bloom in the season following severe black spot damage.
Disease Life Cycle Black spot spores overwinter on infected foliage and canes, including infected foliage that has fallen and been left on the ground. In spring, spores are splashed up onto newly emerging foliage during rains or irrigation. Once the weather begins to stay consistently warm and humid, the spores germinate and infect the plant within one day. Visible symptoms (black spot and some yellowing) will be evident within five days, and it will produce and spread new spores within ten days. The new spores will infect other parts of the plant, or be carried on the wind to any other nearby rose bushes.
Treatment and Prevention There are several organic ways to control black spot. Most of them rely on regular monitoring and upkeep. None of them are difficult and can be accomplished while you're admiring your roses. Plant roses in full sun. If you give your roses a spot where they receive a full six to eight hours of sun per day, you'll not only have plants that grow more robustly, but also plants that are more able to resist black spot. Black spot loves moisture, and, in shade, water evaporates much more slowly. In full sun, evaporation happens more quickly, which not only helps prevent black spot, but other fungal diseases as well.
Plant roses in an area with good air circulation. This accomplishes the same thing as planting in an area with direct sunlight: moisture evaporates more quickly. In addition, with plenty of air circulation, hopefully breezes will blow any newly-germinated black spot spores away from your roses. In an area with poor air circulation, the spores have nowhere to go but back onto your plant and the surrounding soil.: moisture evaporates more quickly. In addition, with plenty of air circulation, hopefully breezes will blow any newly-germinated black spot spores away from your roses. In an area with poor air circulation, the spores have nowhere to go but back onto your plant and the surrounding soil.
Water correctly. Try to avoid overhead irrigation, which wets the foliage. It's more efficient to water at ground level anyway; you lose less water to evaporation. Also, avoid watering late in the day. Water evaporates much slower in cooler evening and nighttime temperatures. Remove leaves that show signs of infection. As soon as you see black spot on your rose foliage, remove any infected leaves. Throw these leaves away. Don't put them in your compost pile. If you check your roses regularly and remove infected foliage immediately, you'll have a good chance of keeping black spot under control and keep it from infecting other parts of the plant.
Keep a clean garden. Pick up and throw away any fallen rose foliage regularly. Especially in late winter, rake up the area around your roses, dispose of any debris, and give the entire area a good three-inch deep layer of mulch. If you do this before new foliage begins to emerge, it's fairly unlikely that you'll have any major issues with black spot.
Choose resistant cultivars. If you've had persistent problems with black spot, be sure to make sure that any new roses you add to your garden are resistant. Your local cooperative extension service will be able to provide you with suggestions. The old remedy of treating black spot with a baking soda spray has been shown to be ineffective. The only way to control black spot organically is to practice the prevention and maintenance tasks above.
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Dummer. ゛☀
2017年09月13日
Dummer. ゛☀
What is Black Spot? Black spot is a fungal disease (Diplocarpon rosae), that affects roses. It causes black spots on leaves, eventually causing the leaves to turn yellow and drop off. Besides looking unsightly, it can seriously weaken the rose plant. Ideal conditions include hot, humid or rainy summers and hot days with cool, damp nights.
Symptoms: Somewhat circular black spots on leaves. They usually occur on the upper sides of leaves, but can also develop on the undersides. The outer margins of the black circles are ragged or feathery and they are usually surrounded by a ring of yellow. Spots begin on the lower foliage and move upward. They can appear as early as when the leaves first unfurl. These spots can enlarge and merge. Severally affected leaves often fall off the plants and left unchecked, the entire plant can defoliate. The fungus can also infect young canes, causing dark purple or black blisters, and even the flowers may show some red spotting. Infected plants will set fewer flower buds and without leaves, the plant becomes stressed and is susceptible to even more problems.
Cultural Controls Growing Conditions - Make the growing conditions less hospitable for black spot. Black spot is easier to prevent than to cure. The spores can remain in the soil and overwinter on leaves and stems, waiting for favorable conditions. They make contact with the rose by splashing up in drops of water. Give the plant what it wants. This is true for avoiding any plant disease. A healthy, vigorous plant is less susceptible to problems. Roses prefer a sunny location with well-draining soil and regular weekly watering.
Air Flow - Provide good air circulation around and through your rose plants. Don't plant your roses too close to other plants. Prune to open the spaces between canes, if the plant gets too dense and air can not get through. Proper Watering - Avoid getting the leaves wet, while watering. There's not much you can do about rain, but at least limit the time the leaves remain wet. Plant resistant cultivars - Roses are often labeled for resistance, from highly resistant on down. While you are looking for black spot resistance, you might as well look for a rose that is also resistant to rust and powdery mildew. Rugosas, the newer shrub and ground cover roses and many of the Canadian Explorer Series, like John Cabot and William Baffin, show good resistance.
Sanitation - Remove any infected leaves and always do a thorough cleanup each fall. Remove and dispose of any remaining leaves, when you do your dormant pruning in late winter/early spring. Spores can remain on leaves and stems throughout and will reinfect whenever conditions are favorable. Within 10 days of the first symptoms, the disease has already started spreading. Spores can spread by water and wind. Prune out any canes showing signs of infection. Prune 6 – 8 inches below the infection and only prune in dry weather. Disinfect your pruners with a 10% bleach solution or alcohol, between cuts. Mulch - Apply a thick layer of mulch around the plants. Mulch will prevent water from splashing up on the plant and spreading spores. Sprays for Treatment and Prevention It is easier to prevent black spot than to cure it, but it is time-consuming.
If black spot is a reoccurring problem in your area, you may need to spray your plants weekly, starting in early spring. Baking soda spray - Dissolve 1 teaspoon baking soda in 1-quart warm water. Add up to 1 teaspoon liquid soap. Spray leaves thoroughly. This mixture works better as a preventive than as a cure. Also offers some protection from powdery mildew. Bordeaux Mix - This is a fungicide that contains copper sulfate and hydrated lime. It can be used as a powder or mixed with water and sprayed. Bordeaux mix also repels some insect pests, but it can burn plant leaves. It is generally used as a preventative in the spring, before plants leaf out.
Insecticidal soaps with added fungicide - These are basically some type of organic fungicide, often sulfur, added to regular insecticidal soap. The soap helps the fungicide adhere to the plant leaves and spread to coat them. Neem Oil - Neem is an organic fungicide and pesticide, derived from the seeds of the neem tree. It gets inside the plant's system, so you don't need to worry about coating everything or reapplying after a rain. However, it can burn plant leaves in hot sun. You should not apply need oil within 2 weeks of using a product containing sulfur.
Sulfur - Sulfur both prevents and gets rid of fungus diseases. It is also used to control several insect pests. However it can be mildly toxic to humans and other animals. You should wear protective clothing when you spray it. It can also corrode metal, so use a plastic sprayer . And it can burn plants leaves in hot weather. Sulfur comes as a finely ground powder. If you prefer to spray it on, look for one labeled as wettable, so that it will mix with water.
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Dummer. ゛☀
2017年09月13日
Dummer. ゛☀
Insects are a fact of life in the garden and that's not a bad thing. Many plants depend on insects for pollination after all. There are many ways that insects can be beneficial partners for us, in the garden. There are also insects who do a lot of damage to flowers and vegetables. It's up to the gardener to try and strike a balance.
Integrated Pest Management The first step in garden insect management is to be aware of who is there and what they're doing. Even some of the so called "pests" are only having a snack as they pass through your garden. You wouldn't want to bring out the spray can to get rid of a monarch butterfly caterpillar who is munching on your parsley. Integrated Pest Management (IPM) is an approach toward insect control that walks the line between catching problems before they escalate and how much damage can you handle before you bring out the heavy artillery. If you can create a type of harmony in your garden, it's good for you, your plants, and the environment.
5 Ways to Keep Pests Out of Your Garden Integrated Pest Management goes beyond monitoring for pest insects. There are steps you can take to make you garden less inviting to those pests and it doesn't take a lot of effort or money. Tweak the cultural conditions of your garden and cut down on future work and problems.
The Good Guys - Beneficial Insects I mentioned that not all insects are out to wreak havoc on your garden. Some go beyond pollinating in their beneficial impact. There are insects who prey on some of those infuriating pests, like aphids and cabage worms. These are the insects we want to encourage to feel at home in our gardens and all it takes is knowing which plants they are attracted to and giving them cover in the garden.
A Gallery of Garden Insects and Disease To keep the peace in the garden, you have to know what your dealing with and that starts with identifying what is causing the problem. It's not uncommon to mistake a disease for insect damage or the other way around and no amount of pesticide is going to cure a fungal disease. Here are photos of some common insect pests and the kind of damage they do, along with some possible controls. Gallery of Insects and Diseases 4 Pests and a Good Guy You Should Get to Know How Gardens Deal with Slugs Earwigs - Friend or Foe?
Indoor Pests of Houseplants I don't know how they do it, but some insect pests find their way into your home and onto your houseplants. (How do they know there are plants inside?) Indoor pests can be even harder to control than garden pests because there are no natural predators indoors - or at least not many. The pests profiled here tend to hide under leaves unnoticed until the problem is extensive. Check for them every time you water, to stay on top of the situation.
Organic Pest Control Choices Even if your precious plants are being devoured by marauding pests, you don't have to spray toxic chemicals with abandon. There are less toxic options. Do yourself and your plants a favor by always starting with the least toxic solution first. If you can catch the problem early, that's all you should need. Useful Pest ID Sites Thank goodness for the internet. We now have access to thousands of pages of research and recommendations for just about everything. I always refer people to their local cooperative extension office, because they know what problems are affecting your area and what the best options are for controlling it. Most have Master Gardeners who will answer your questions via phone and they all have web sites with frequently asked questions. Here are a few of my favorite go to sites for answers to my garden problems - and yes, I do have some.
It Takes More than One Approach Gardening is a juggling act. We create. We destroy. Too much one way or the other and that fragile balance is lost. Make pest management practices a regular part of your gardening chores and just may be able to stay in that delicate middle ground where everyone is happy.
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