Identification of Diseases on Strawberry Fruit

Table of Contents

1. Anthracnose Fruit Rot
2. Botrytis Grey Mould
3. Leather Fruit Rot
4. Related Links

Anthracnose Fruit Rot

Symptoms:

Firm round lesions, slightly sunken, initially orange or tan in colour. These lesions turn brown, then black with age and produce salmon-coloured spore masses.

Firm round lesion on strawberry fruit.

This anthracnose lesion has salmon-coloured spores developing in the center.
Used with permission from Uinversity of California Statewide IPM Project, J. K. Clark, photographer.

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Close-up of anthracnose lesions on a cluster of fruit.

Source of Disease:

Rain-splashed spores from infected plants or recently contaminated soil. Spores can also spread by movement of workers, animals and equipment.

Factors that Favour Disease:

Warm, humid weather, splashing rain, plasticulture.

Control:

Purchase plants that are free from disease. Do not plant strawberries after strawberries. Apply fungicides as outlined in Publication #360, Fruit Production Recommendations

Botrytis Grey Mould

Symptoms:

Brown lesions form at calyx end of fruit and produce grey-white fungal growth. The lesions have no distinct border. They produce powdery spores that are easily airborne.

Botrytis lesion at calyx end of fruit.

Grey powdery spores produced on mature Botrytis lesion.

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Both green and ripe fruit showing soft brown Botrytis lesion at calyx end.

Source of Disease:

Airborne spores from plant debris and old strawberry leaves.

Factors that Favour Disease:

Moderate temperatures and long wetting periods or periods of high humidity, during bloom. Dense foliage and wide rows which keep plants wet longer. All strawberry varieties are susceptible to Botrytis, but some varieties are much more susceptible than others are.

Control:

Crop management practices that keep rows narrow and encourage air flow in the row will help reduce disease. Apply fungicides during bloom as outlined in Publication #360, Fruit Production Recommendations.

Leather Fruit Rot

Symptoms:

Fruit surface is dull, discoloured and may be tough and leathery. The vascular tissue to the seeds is discoloured. Infected fruit has a foul odour and taste.

Fruit on right showing symptoms of leather rot. Entire fruit is discoloured and skin is leathery.
Used with permission from University of California Statewide IPM Project, G. Browne, photographer.

Off-colour lesions on fruit infected with leather rot.

Immature fruit showing brownish discolouration from leather rot.

Source of the Disease:

Soil-borne spores that travel in surface water and saturated soil. Spores contact fruit in rain-splash, standing water or soil to fruit contact.

Factors that Favour Disease:

Saturated soil conditions, standing water, soil-fruit contact. Conditions that favour Botrytis will also favour leather rot.

Control:

Grow strawberries only on sites with excellent soil drainage, where standing water does not occur. Growing strawberries on raised bed or ridges can reduce leather rot problems. An adequate layer of straw mulch is extremely important for prevention of leather rot.

Related Links

• Publication 513, Growing Strawberries in Ontario
• Publication 360, Fruit Production Recommendations

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