Stories related to plant diseasesSoil solarization is the simple process of putting transparent plastic sheeting over moist tilled soil during the warmest and sunniest months of the year. The clear plastic traps the heat of the sun, causing physical, chemical and biological changes to occur in the soil. Oregon State University crop scientist Dan McGrath explains about how it works, research results and how home gardeners can do their own solarization at home.
Prolonged wet, cool weather in May and June is likely to bring on canker disease problems in cherry and other stone fruit trees in Oregon. Symptoms and treatments from the OSU Extension Service. A dry winter followed by a wet spring is fostering many outbreaks of fungal and bacterial diseases on plants this growing season, according to Jay Pscheidt, plant pathologist with the Oregon State University Extension Service. But now that they are established, it is hard to eradicate them, as prevention is the only sound strategy for control. Since the fungal diseases rust, powdery mildew and blackspot are common in rose gardens in the Pacific Northwest, it is prudent to purchase and plant disease-resistant rose varieties. You’ll save yourself a lot of frustration, time and expense.
Before buying new rose plants, read the tags on the roses in the store or the information in the catalog. The tag or description of each variety should state its particular disease resistances.
Included are two lists of roses, the first grown in the Oregon Coast Range by OSU Master Gardener Pat Patterson. The second list is recommended by the OSU Extension Service, grown out and tested at the Portland International Rose Test Garden and the Longview, Washington Public Library Rose Garden. Visit OSU Extension Service’s On-line Guide to Plant Disease Control for the complete list of disease resistant roses. Here's how to help prevent plant diseases from developing. In the fall, remove diseased plants and do general clean up around the garden. Do you have ripe strawberries that are turning brown and soft? Or are you finding strawberries that are covered in gray fuzzy mold? Your plants may be suffering from gray mold, also known as Botrytis fruit rot. Symptoms and cultural controls. In western Oregon, apple scab is the apple disease that requires the greatest number of fungicidal sprays for control. An alternative to using fungicides is to plant scab-immune or resistant varieties. OSU has tested scab-immune and scab-resistant apple varieties at their experimental farms in Corvallis. Lists of scab-immune and resistant and fire blight resistant apples for both western and eastern Oregon provided. EC 1334 described. Biology, life cycle and symptoms of the Dutch elm disease from the OSU Extension Service. Web link for more information. Autumn is a good time to plant trees. It is also a useful time to look around and note what types of trees look under stress in your region of the state. Nurseries sell all types of trees, a few of which don’t tend to do real well in the Pacific Northwest. Other types of trees seem to thrive, no matter what. Examples of problem trees and trees that thrive in the Pacific Northwest are included. Also included is ordering information on OSU Extension publication, PNW 500, “Plant Materials for Landscaping.” Autumn rains foster plant disease outbreaks in home gardens. Increased moisture means root rot diseases caused by the fungus Phytophthora, plant diebacks caused by the bacterium Pseudomonas and cankers of apple and cypress and a blight of Berckman's arborvitae. Fall rains that hit early produce lots of different rots in late ripening fruit crops like grapes and apples. Basic sanitation practices in the yard, including removing debris, leaves and diseased plant parts. If you bring a sample of a diseased plant to a county office of the Oregon State University Extension Service, a Master Gardener or home horticulture agent will try to answer your question. But, if the problem is too tricky to diagnose by simple means, they may want to send it to OSU’s Plant Clinic in Corvallis. If so, be prepared to be billed for the service. Hints for how to collect plant and information to include with the plant. “Controlling Diseases and Aphids on Your Roses,” is an OSU Extension 6-page circular about common rose afflictions: black spot, rust, powdery mildew and aphids. It identifies conditions that favor infection and suggests practices to help effectively control these problems. Rather than discussing controls for each specific problem, the OSU publication treats the rose as a whole organism. It offers a year-round integrated approach to pest and disease control. Prevention is the first step in controlling diseases and insect pests in home orchards. Many problems can be avoided by choosing fruit tree varieties that are resistant, and providing them with proper care. To avoid some of the pests and diseases that can harm your fruit trees before the next growing season, late fall is the best time clean up the area where your fruit trees grow. Have you noticed Douglas fir trees turning reddish-brown and dying around the Willamette Valley, Coast Range, or foothills of the Cascades? Are you noticing swollen-looking leaves on your azalea? Are they enlarged, pale green, grayish or whitish colored and fleshy looking? Your plants may be suffering from azalea leaf gall. Wet weather in April and May builds potential for apple scab, a fungal disease of apples. When choosing plants for your yard and veggie garden, you'll save yourself a lot of heartache as well as money if you choose disease-resistant varieties, advised Jay Pscheidt, plant pathologist with the Oregon State University Extension Service. Daylily rust has been confirmed recently at a nursery in the Willamette Valley, according to Melodie Putnam, plant pathologist for Oregon State University Extension Service. When choosing plants for your yard and veggie garden, you'll save yourself a lot of heartache as well as money if you choose disease-resistant varieties. Mint compost, the spent hay left after the mint oil has been extracted, is a rich source of organic matter that savvy gardeners use to enrich their soil. But what about the fungus Verticillium dahliae, that often infects peppermint? Can the compost be a vehicle for introducing this disease-causing fungus into your garden? There is a killer on the move. Sudden Oak Death (SOD), a new disease that has caused dramatic mortality to coastal California oaks, has recently been discovered in southwestern Oregon. If you bring a sample of a diseased plant to a county office of the Oregon State University Extension Service, a Master Gardener or home horticulture agent will try to answer your question. Fall rains bring on extra phone calls for at least two researchers at Oregon State University. Both Jay Pscheidt, a plant pathologist at OSU and George Taylor, the state climatologist with the Oregon Climate Service at OSU, get extra busy this time of year. Let's say your tomato plants have dark, weepy sores. Or the rhododendron leaves along your house are yellow and droopy. Perhaps you'd like to know what gray sticky gunk is on your honeysuckle buds. Love to grow your own tomatoes? Summer heat brings a host of problems to the tomato patch. Over the past few years, agricultural scientists at Oregon State University and the U.S. Department of Agriculture (USDA) in Corvallis have been experimenting with a simple, non-chemical means of combating plant diseases and weeds called "soil solarization." During the past few years, agricultural scientists at Oregon State University and the U.S. Department of Agriculture in Corvallis have been experimenting with a simple, non-chemical means of combating plant diseases and weeds called "soil solarization." Apples signal a change of season, as a strawberry-sweet summer turns cool and crisp. But the apple tree in your back yard may not look so lyrical right now. Our prolonged wet, cool spring weather is likely to bring on canker disease problems in cherry and other stone fruit trees. The third treatment for the disease peach leaf curl should be applied in the late winter, around Feb. 15. January is time for the second treatment of fungicide for peach leaf curl, a fungal disease that commonly afflicts peaches and nectarines. Leaf fall in the autumn is time to start treating for peach leaf curl. Apply a sulfur or copper-based fungicide, sometimes called "dormant spray," three to four times to peach and nectarine trees during the dormant and delayed dormant season. Treating for fruit tree pests in the cool, dormant months is much more effective than waiting until the weather warms up and pests become active in spring and summer. Many garden and landscape plants are susceptible to one or more plant diseases, which can reduce the yield of fruit and vegetable crops and disfigure ornamental trees, shrubs, and flowers. The Oregon State University has recently received inquiries about white cottony patches in grass in home lawns in the Willamette Valley. The Oregon State University Extension Service gets hordes of calls during the wet season from homeowners complaining of "red thread" disease on their lawns.
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