There are many pests and diseases in cotton in summer and autumn. What are the main pests and diseases in cotton in summer and autumn?

Symptoms of cotton bollworm damage: the second generation (boll stage). At the growing point, the larvae destroy the small leaf buds around the top center into incomplete shapes, with tiny insect droppings and deformed leaves. The growing point is often destroyed, so that the top of the cotton stem stops growing, and thick bare branches grow from several axils below the top, and there are basically no buds on them, which makes the whole cotton plant become cotton with only long leaves and no bare stems, commonly known as "male cotton".

The top young leaves were killed and eaten into many small holes; Larvae hide in bracts and eat buds. Buds fall off quickly after opening; Stamens and styles of flowers are eaten; The base of the ovary is decayed into a victim, and the flowers of the victim often do not bear bells. The fourth generation (boll stage) hazard. There are holes at the base of cotton bolls, and there are insect droppings near the holes, and most of the eaten larvae are exposed outside the cotton bolls; Cotton bolls are prone to mildew and fall off in the rain, and the damaged parts that don't fall off become stiff petals, so do flower buds. Control methods: agricultural control: poplar branches attract moths; Maize and sorghum disease induction areas; Field farming management and agricultural operation reduce insect population density. Biological control: using microbial insecticides to treat cotton bollworm. Protect and utilize natural enemies.

There are many natural enemies of Helicoverpa armigera, such as trilobites, Apodemus odontoides, parasites, lacewings, ladybugs, spiders and other parasitic eggs and larvae, which play a good role in controlling the harm of Helicoverpa armigera. There are 1 newly hatched larvae of Helicoverpa armigera, surrounded by a litter of larvae, mainly for selection and treatment, and control before the larvae spread. The damage rate of cotton thrips is 2%. Attention should be paid to the quality of pesticide application, alternate pesticide application and spraying with motor sprayer. The prevention time should be after 4 pm.

For larvae, cotton farmers should be organized to catch them manually in the morning. The following control agents are recommended. Cotton thrips and cotton aphids: use acetamiprid, Emile, aphid lichens, such as imidacloprid, etc. Cotton worm: Fipronil (relast), acephate, chlorpyrifos, beta-cypermethrin, etc. Four cotton mites: sokalin, pyridazine, abamectin, propargite, abamectin-pyridazine, abamectin-chai, etc. Cotton bollworm, Spodoptera litura. Emamectin, fenpropathrin, fipronil, phoxim+pyrethroid pesticide, profenofos, etc. Cotton boll diseases: Pinocchio, carbendazim, Lubang 9 bacterial map, fresh-keeping gram, etc.