Diseases and pests of leaf vegetables
Lettuce mosaic, lettuce leaf kidney disease and mosaic, spinach yellow spot and jaundice are the most common viral diseases of leaf vegetables. These diseases mainly cause inhibition of plant growth, distortion and undesirable discoloration of the leaf plates, thus reducing the quality and amount of the crop. To prevent these diseases, use healthy seeds for sowing, reject seedling with symptoms of virosis, fight aphids.
Other common diseases include:
Bacterial rot of lettuce and endive caused mainly by the bacterium Pseudomonas marginalis. These pathogens1 initially produce dark spots, rotting spots on the edges of older leaves. Later they also attack younger leaf blades and noodles, making the whole plant rot. Bacteria overwinter in plant debris in the soil, therefore, after harvesting, carefully remove any leftovers and burn them, not compost.
Lettuce downy mildew is a fungal disease that develops in high air humidity and moderate temperature (15-17°C). Large light green or yellow angular spots form on the underside of the leaves and a slight white coating appears. The disease affects mainly head lettuce and endive. Infested plants should be removed and destroyed, apply proper alternation. Plants should be watered in the morning, ventilate the frame strongly. In the early stages of plant growth, they can be sprayed with a concentration of Cynkotox 0,3% or Zinc copper 0,3%.
Cottage cheese rot and gray mold on lettuce are fungal diseases, and pathogens attack plants of all ages, infecting the base of the petioles and causing them to rot when wet. The disease gradually spreads to the gulls as well, as a result of which whole plants wilt and die. In curd rot, the rotting parts of the plants become white, woolly mycelium, among which the pathogen produces several millimeters in size, black, hard spore organs. Gray mold is a characteristic feature of gray mold, dusty coating. Both fungi hibernate in the soil. These diseases are prevented in greenhouses and frames by disinfecting the soil (preferably with a couple) before planting lettuce. In an infected field, lettuce cultivation must be interrupted for several years. Spraying the plants with Sadoplon can be used until the leaves are curled up into their heads 75 (0,3%) as soon as you notice the first diseased plants.
Downy mildew of spinach. It usually attacks the outer leaves of the spinach. Large yellow spots appear on the leaves, a gray-violet coating forms on the underside of the leaf. Infected plants turn black and die. The disease is prevented by using sparse sowing, proper alternation, weed control, collecting and removing plant debris after harvest.
Plants of this group are attacked by various pests, and in particular by:
Wireworms – yellow, shiny larvae, which gnaw at the plants at the root, causing them to wilt and die. If we suspect the presence of these pests, before sowing or planting lettuce, the bed should be dug out in sunny weather, that the larvae and eggs extracted to the surface die. In the event of a massive appearance of pests, it is recommended to scatter Basudin in the fall or spring before sowing or planting 10 G (8 g na 1 m2), mixing it with 10-, 20-centimeter layer of soil.
Farmers – they are thick, gray caterpillars, curling up when touched. In spring, they nibble on young plants and pull them into the ground. They are multivorous pests and we fight them in the same way as wireworms.
Similarly, you have to fight the cockchafer grubs, which nibble at the roots of young and old plants. These grubs live in the soil 3-4 years.
Leaf vegetables are attacked by aphids, a duster of beetroot and a field slug. Insecticides with a short waiting period are used on aphids – Pirimor 50 DP in concentration 0,05% or Liquid Sadophos 30 in concentration 0,3%. The beetroot cream is combated during the egg-laying period by spraying liquid Foschlor 50 in concentration 0,2% or Insectophos liquid 50 in concentration 0,15%. The grasshopper is a snail, whose body is elongated (5-6 cm), light yellow, covered with mucus. There are irregular holes in the lettuce leaves. It is fought against, sprinkling in the evening (during the day it hides among the leaves, and it forages in the evening) the soil next to plants with quicklime (40 g na 1 m2).
Leaf vegetables are also attacked by snacks.