What are the hazards of green onion thistle pests? How to prevent and cure it?

Thrips pests can occur all the year round, mainly in the open field in spring, summer and autumn, and more seriously in the greenhouse in winter. If green onions are attacked by thrips, it will have a great impact on the yield and quality of green onions. Let's learn about the harm of thrips and shallot pests. How to prevent and cure it?

First, what are the hazards of thrips with green onions?

Onion thrips, also known as tobacco thrips and cotton thrips, are larger, with a body length of about 1.2-1.4mm, and body colors ranging from light yellow to dark brown. The annual occurrence of 8-10 generations, generations overlap. Onion thrips have a wide range of hosts, with more than 30 species. The main crops affected are Liliaceae vegetables such as onions, onions and garlic, and cucurbitaceae, Solanaceae vegetables and cotton. The environmental conditions of protected cultivation are beneficial to the occurrence of thrips. Because of its fast reproduction speed, if it is not controlled in time, it will cause disastrous harm and seriously affect the growth of plants and the quality of fruits.

The occurrence peak of thistle pest is in autumn or November-December in winter, and the second peak is from March to May. Female adults mainly carry out parthenogenesis, occasionally bisexual reproduction, and it is very difficult to see males. The eggs are scattered in the mesophyll tissue, with 22-35 eggs per female. The life span of female adults is 8-10 days. The egg period is 6-7 days from May to June. The nymphs stop feeding at the back of the leaves until the end of their old age and fall into the topsoil to pupate.

Thrips like warm, dry weather, with a suitable temperature of 23 ℃-28 ℃ and a suitable air humidity of 40%, 70%. Too much humidity can not survive. When the humidity reaches 100% and the temperature reaches 31 ℃, all nymphs die. In the rainy season, in case of continuous overcast and rainy, stagnant water between the leaf axils of onions can lead to the death of nymphs. The soil is hardened after heavy rain or watering, so that nymphs cannot be buried into pupae and pupae cannot hatch adults.

Second, how to prevent and control the insect pests of thrips with green onions?

1. Clean the countryside

In early spring, weeds and fallen leaves of onions and garlic fields and their surrounding plants were removed, concentrated burning, and overwintering insect sources were eliminated.

2. Strengthen the management of fertilizer and water

Strengthen fertilizer and water management, especially in dry weather, we should pay attention to watering, promote plant growth and destroy the ecological environment conducive to the occurrence of onion thrips.

3. Chemical control

Timely spraying imidacloprid, imidacloprid, enantiomide, thiazide, furosemide. It can also control stinging pests such as blind bugs and leafhoppers, and can also control leaf-eating pests such as Plutella xylostella, Plutella xylostella, Helicoverpa armigera, etc. fungicides such as difenoconazole, cyanothrin, tebuconazole, enamylmorpholine, propionamide and other fungicides can also control downy mildew, brown spot, blight and other diseases. When the damage of thrips is more serious, ethyl spinosad can be used for control, and attention should be paid to the rotational use of drugs to reduce the resistance of thrips to pesticides. However, because the leaves of Welsh onion are relatively smooth, foliar spreading agent or neutral detergent can be added during spraying to increase adhesion and improve spraying effect. When it is serious, it should be sprayed continuously at intervals of 5 to 7 days, and the prevention and control of leaf pests should be timely to avoid increasing the difficulty of prevention and control after drilling.