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March Highlights

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.

Bacterial disorders

Damage caused by species of Pseudomonas including Pseudomonas syringae, on woody ornamentals are typically seen at this time of year. 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.

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lilac-Pseudomonas syringae





Bacterial stem galls on forsythia have been confirmed in the OSU Plant Clinic as Pseudomonas savastanoi

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forsythia bacterial stem gall

Fungal disorders

Red crown rot in hop is caused by a fungus that invades injured plant tissue.  Vegetative spores survive on the plants, in soil, and in plant debris. Plants are weak and yellowish, and roots look twisted and thickened with the centers crumbly and orange to red in color.

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hop red crown rot

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.

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red clover

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.

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wheat - bydv

Abiotic disorders

The very cold spell in December and again in February (although less so) have caused winter injury in many plants and left them susceptible to secondary bacterial and fungal infections.

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.

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Nutrient management is an important part of growing healthy plants and regular soil testing can identify problems that may be corrected. This article shows how to interpret your soil test results, and also some of the problems that arise when nutrients are out of balance. Requirements for specific crops are available through the OSU Extension Catalog.

GENERAL NOTE: Taking action this month near bud break for many crops (such as lilac, rose, peaches, and hazelnut) with timely disease and pest management programs will reduce the need to watch for things next month and this summer.

 see also "The Plant Clinic Year"