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Things to watch for during March From our experience of samples we have received during March in previous years in the OSU Plant Clinic, this page will highlight some problems that may occur this month. Fungal disorders Fusarium root and crown rot in field crops of clover may be caused by a combination of stresses, including winter injury, nutrient deficiencies, and wounding. Insects may be a cause of wounding, especially the larvae or root borers and weevils. Plants may be pale and stunted with darkened crowns and roots. Click on image for more informaiton Bacterial disorders Damage caused by species of Pseudomonas including Pseudomonas syringae, on woody ornamentals are typically seen at this time of year; especially now after the prolonged cold temperatures at the end of 2008, and the periods of frosty mornings followed by moist or wet conditions. These bacteria overwinter in diseased twigs or as epiphytes on healthy wood. Tissues that have suffered injury from frost, as well as from pruning, unsuitable soil pH, poor nutrition, or infection by other pathogens, are predisposed to Pseudomonas diseases and exhibit a variety of symptoms. Click on images for more information Viral disorders Symptoms of Fall infection of Barley Yellow Dwarf Virus (BYDV) on fescue, rye, wheat and many other cultivated and wild grasses may first appear in the spring as yellowish leaf tips (reddish in oats). BYDV is transmitted by several species of aphid. Click on image for more information
Abiotic disorders A physiological abnormality related to environmental conditions during potato growth and harvest may result in tubers with hollow heart or internal black spot. The dark area usually begins in the center, or at the stem end, and develops into a hollow. Some varieties of potato are more susceptible than others, and there is no way to distinguish these tubers until they are cut. There is no disease associated with this condition. Click on image for more informaiton
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May 14, 2009
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