Alternaria Leaf Blight in Cucumbers
Symptoms
Small, yellow-brown spots with yellow or green halos first appearing on the oldest leaves; as the disease progresses, lesions enlarge and become large necrotic patches; lesions merge, leaves begin to curl and eventually die.
Agent
Fungus
Development Conditions of the Disease
The disease is common in growing regions where temperatures are high and rainfall is frequent.
Control Methods
To reduce inoculum levels, cucurbits should be rotated with another product every 2 years; crop residues should be removed from the field as soon as possible after harvest or plowed deep into the soil; application of appropriate protective fungicides can help slow the development of the disease; irrigate plants from the base, not from above, to reduce leaf wetness periods that cause the disease to develop and spread.
Cucumber Anthracnose
Symptoms
Brown, roughly circular lesions with yellow margins on leaves, petioles, stems and/or fruits; lesions on resistant varieties appear bronze with green margins; lesions dry out and fall from the leaves.
Agent
Fungus
Development Conditions of the Disease
The disease likes warm weather.
Control Methods
Plant resistant varieties; use only certified seeds; apply appropriate protective fungicides; rotate plants every year.
Cercospora Leaf Spot in Cucumbers
Symptoms
Initial symptoms of the disease appear as small spots with light to tan brown centers on older leaves; as the disease progresses, lesions grow to cover large areas of the leaf surface; lesions may have a dark border and be surrounded by a chlorotic area; the centers of the lesions may become brittle and crack.
Agent
Fungus
Development Conditions of the Disease
The fungus lives on plant residues; spreads by wind and water splashing; occurs mainly in tropical and subtropical growing regions.
Control Methods
To prevent further spread, diseased plants should be removed and destroyed; crop residues should be removed after harvest or plowed deep into the soil to reduce inoculation.
Yorumlar