Preventing Harmful Lettuce Diseases
Lettuce is vulnerable to many types of diseases, particularly fungal infections. It has been observed that lettuce harvested during the summer and fall season tends to attract more pests. The combination of pests, humid conditions and leafy lettuce leaves create a breeding ground for plant diseases. You should equip yourself with a basic understanding about each type of lettuce disease and learn how to prevent them.
Anthracnose Fungal Infection
This destructive fungal infection spreads quickly through a lettuce crop, particularly during rainy seasons. The disease is communicated to surrounding plants through weathered, rotting foliage or garden debris. Plants infected with Anthracnose should never be used for composting. You should dig these plants and burn them. Ensure proper garden hygiene by clearing debris that contains any kind of dead plant matter. Anthracnose infections can survive in a dormant form in the soil and suddenly surface among the plants when the conditions are moist.
Mosaic Viral Infection
The mosaic virus is carried by garden pests like aphids. Young lettuce plants affected by mosaic show a curled-up foliage pattern. There is significant brown spotting all over the lettuce foliage. You should use organic insecticides to control aphid populations. Using a high-pressure hose for watering helps to destroy the eggs laid by aphids. Once the aphids have been eradicated, you can keep them away by regularly spraying the lettuce with a mixture of soap water and neem seed oil. Mosaic-infected lettuce should be dug and destroyed, as the infection transmits very quickly.
Bottom Rot Disease
This fungal disease is caused by the Rhizoctonia solani fungus. It is more common among the mature and ready-for-harvest lettuce. It is often propagated by the presence of old, rotting garden mulch. Lettuce with bottom rotting shows severe necrosis along the stem and the basal leaves. The first symptoms are small brown spots on the lower leaves. Bottom rotting breeds in waterlogged garden beds. A properly mulched garden bed needs proper drainage. You should not over-water the lettuce soil bed. You can try watering the plant with a soaker hose. This helps control watering by minimizing water spraying. Another useful but slightly expensive option is using drip irrigation.
Gray Mold Disease
Lettuce molding is commonly caused by the Botrytis fungus. This is the most common form of lettuce-based fungal infection. The molded spinach seedlings rot with a typical look of being water-soaked. This is why gray mold is often called the Damping-off disease. This is a hard-to-control disease, since it spreads through the soil, quickly devouring the entire lettuce crop. The mold patterns are clearly visible on the lettuce stem and leaves touching the soil. Sometimes small, hard pea-like formations are found on lettuce during the winter. To avoid lettuce mold. regularly use organic fungicide. Fungicidal sprays should be initiated as soon as lettuce is planted to avoid molding problems.
This is an uncommon bacterial infection of lettuce caused by the Pseudomonas bacteria. It is transmitted through a soil bed that is perpetually wet or concentrated with rotting organic matter. This is one of the most difficult lettuce diseases to detect since it affects the inner leaves first. The only way to guard your lettuce spread against varnish spotting is to use a crop-rotation cycle every year.