Disease guide

Storm Damage

Causal Agent

Environmental

Distribution

Worldwide

Symptoms

Injury from wind, pelting rain or hail is usually visible only on the side of leaves that were facing prevailing winds during a storm. Spots develop that are typically 1-5 mm (0.06 – 0.2 in.) in diameter, white to yellow in color and round or irregular in shape. Although rain damage is rarely serious, hail damage may defoliate a crop. Storm damage may be confused with Botrytis leaf blight or herbicide injury and can also make plants more susceptible to fungal and bacterial pathogens.

Foliar lesions caused by hail. Foliar lesions caused by hail.

Conditions for Development

Raindrops, hailstones and soil particles blown by strong winds wound leaf, neck and flower stalk tissues.

Control

In areas that are subject to storms, seed cereal crops with onions to act as a wind break. Once the onion seedlings are established use selective herbicides to kill the cereal crop. Spray broad spectrum fungicides on storm damaged plants to reduce the risk of secondary infections.

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