Why does zucchini produce whiteflies? What are the prevention and control techniques?

Zucchini is a disease that is prone to occur in dry and hot climates, especially during the months. Zucchini has a wide range of hosts, mixed diets, fast reproduction, short life cycle, large egg production, strong migration and mobility, and is extremely difficult to control. Before raising seedlings, thoroughly fumigate to kill the remaining insects in the nursery greenhouse, eradicate the residual weeds, install screens at the vents to prevent the migration of insect sources, and cultivate insect-free seedlings; Fumigation should be carried out before greenhouse planting.

In autumn, whiteflies should avoid planting vegetables such as melons, nightshades, and beans that whiteflies like to reduce the migration of whiteflies to greenhouses. According to the strong trend of whiteflies turning yellow, in the early stage of whitefly, yellow boards are hung in the protected area, coated with oil, and placed above the plants between the rows to trap and kill the adults.

The whitefly is a highly transmissible, disgusting pest characterized by a white powdery substance on its body. It mostly occurs on the underside of zucchini branches and leaves, especially the new young leaves are susceptible. At the onset of the disease, it will be found that there are dense pale green particles on the leaves, which seriously affects the growth of zucchini.

After illness, it is best to remove the diseased leaves and focus on spraying the back of the leaves. Fumigation of greenhouses before vegetable seedlings in the reserve can reduce the population base. Removing weeds from residual plants and adding a layer of nylon filament to the vents of the greenhouse can avoid foreign insect sources.

Try to avoid mixing, especially zucchini, cucumbers, tomatoes, and kidney beans. Pay attention to adjusting the sowing date and crop residues, that is, the first crop is arranged with celery, bell pepper and other vegetables with light damage from whitefly.

The natural enemies of the whitefly are abundant. Its parasitic natural enemies include peach aphid and peach aphid, predatory natural enemies include ladybugs, lacewings, bugs and predatory mites, and parasitic fungi include Penicillium rosa, Verticillium cereus and Beauveria bassiana. They have considerable inhibitory capacity against whiteflies and should be protected and utilized.

Old nymphs are mostly found in the lower leaves. When pruning, some old leaves should be appropriately removed, buried deep or incinerated to reduce the population. Physical control:

Yellow has a strong trapping effect on adult whiteflies, and yellow plates can be set up in the greenhouse to trap and kill adults. In addition to directly sucking and harming crops, causing plant decline, leaf yellowing and falling off, adults can also secrete honeydew to induce coal ash spot, causing branches and leaves to turn black and seriously reduce crop yield and quality.

The adult body of the whitefly is millimeters long, and the white wax powder covers the entire body, hence the name. Adult worms suck sap from the underside of the leaves. Adults are tender and usually live on the upper young leaves of zucchini seedlings, and the damaged leaves dry out.

To combat whiteflies, you can do the following: 1Before planting seedlings, completely remove and kill residual insects in the nursery greenhouse, ** weeds, install mesh windows on the vents to prevent the migration of insect sources, and plant insect-free species; Fumigation should be carried out before planting in a greenhouse. In the vicinity of the greenhouse, try not to plant whitefly melons, nightshade fruits, legumes, and other vegetables that whiteflies like to reduce the migration of whiteflies into the greenhouse. 2.To take advantage of the whitefly's yellowing tendency, in the early stages of the whitefly's appearance, hang it in a sheltered area, hang the yellow plate on the oil, and place it on top of the plant between the two rows to catch and kill the adults.

Bemisi whitefly is a common pest and disease in dry climates. Prevention and control methods of zucchini whitefly:1

Before seedlings, thoroughly fumigate the residual insect population in the seedling greenhouse; Fumigation should be carried out before greenhouse planting, and near the greenhouse, try to avoid planting melons, eggplant fruits, beans and other whitefly favorite vegetables in autumn to reduce the migration of whiteflies to the greenhouse. 2.At the beginning of the whitefly outbreak, the yellow plate is hung in the protected area, coated with engine oil, and placed on top of the plants between the rows to trap the adults.

3.Spray as early as possible when whitefly density is low, 1 time a week, 3 times in a row.

As the area under zucchini cultivation increases, so does the damage caused by various pests and diseases, and farmers must take timely measures to deal with it. This article summarizes in detail the symptoms, occurrence rules and control methods of zucchini whitefly, hoping to help farmers better deal with the pest.

Symptoms: The needle-like mouthparts of its larvae and adults suck the juice of zucchini plants, causing leaves to lose green, wilt, and even die, while adults and larvae can also discharge a large amount of honeydew, causing coal stain disease, polluting leaves and melon strips, affecting photosynthesis, reducing product quality, and spreading viral diseases.

Occurrence rule: more than 10 generations can occur every year under greenhouse conditions, and various insect states overwinter in the greenhouse and continue to cause damage. Adults like cucumbers, eggplants, tomatoes, beans and other vegetables, live in groups on the back of young leaves and lay eggs, before the host plant tops, adults always chase the top young leaves with the growth of the plant, so the distribution of whiteflies from top to bottom on crops is newly laid green eggs, blackened eggs, young nymphs, old nymphs, pseudopupa.

The eggs laid by the newly emerged adults are inserted into the leaf tissue from the stomata by the egg stalk, which maintains a water balance with the host plant and is very difficult to fall off. Nymphs can do short distances on the dorsal surface of the leaf within 3 days after hatching, and when the mouthparts are inserted into the human leaf tissue, they lose the ability to crawl and begin to live a sessile life.

Prevention and control methods: 1Agricultural control. Strengthen cultivation management, cultivate "insect-free seedlings" as the main measures, rationally use chemical pesticides, and actively carry out biological and physical control.

2.Biocontrol. Can artificially breed and release the aphid wasp, when the whitefly adult on the greenhouse pepper is less than 5 plants, according to the amount of 15 plants to release the aphid wasp adult, every 2 weeks 1 time, a total of 3 times, parasitic wasps can establish a population in the greenhouse and can effectively control the whitefly pest.

3.Physical control:Yellow has a strong bending and strong attraction effect on whitefly adults, and yellow boards (1m fiberboard or cardboard, painted orange-yellow, and then coated with a layer of viscous oil, 32-34 traps per mu to trap adults have a significant effect.

The yellow plate is set between the rows and the height of the plant, and the sticky oil (generally mixed with No. 10 engine oil and a little butter) is reapplied once in 7-10 days to prevent oil droplets from causing burns on the crop.

4.Chemical control. It can be controlled with 75% spirometroethyl ester pymetrozine water dispersible granules 8 12 g mu, or 60% pymetrozine dinotefuran water dispersible granules, or 15% avermectin spirometallis ethyl ester 20 45 g mu or flupyranone spiranone ethyl ester 30 40 ml mu.