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Things to watch for during February From our experience of samples we have received during February in previous years in the OSU Plant Clinic, this page will highlight some problems that may occur this month. Fungal disorders Black root rot is caused by a fungal pathogen that can affect many plants including ornamentals such as begonia, pansy, fuchsia, and geranium. The fungal spores persist in soil, and soil based growing media may be a source of infection. Symptoms are like those for many root diseases (yellowing, stunting and wilting) but eventually the roots develop flat black lesions caused by the formation of spores on and inside the root. click on image for more information Bacterial disorders Crown gall can significantly affect grape production on affected vines. The causal bacterium survives in plant debris, old gallls and infected vines, and enters the plant through wounds. The bacterium induces gall formation in the plant tissue, especially at the crown, and galled vines grow poorly or die. click on image for more information
Viral disorders Impatiens Necrotic Spot Virus can be devastating for greenhouse ornamentals. This virus used to be called the Impatiens strain of the Tomato Spotted Wilt Virus. The virus is spread by adult thrips that acquired the virus as larvae while feeding on infected plants. Young plants may be most severely affected and symptoms include necrotic spots on leaves, discolored areas along leaf veins, leaf yellowing, leaf distortion, and blackening of growing points. click on image for more information
Abiotic disorders Excess fertilizer can cause tip burn, marginal leaf scorch, and on some plants, interveinal necrosis beginning at the leaf margin and progressing toward the midvein. The injury is caused by the accumulation of salts in the soil surrounding the roots which in turn slows the uptake of water, and results in accumulation of salts in the plant tissues. Flushing with water may rectify the situation. click on image for more information
see also "The Plant Clinic Year"
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May 14, 2009
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