Specific drug for gray planthopper

Grey planthopper is widely distributed in East Asia, Southeast Asia, Europe and North Africa, and is distributed all over the country, especially in the Yangtze River Basin and northern rice areas. So what are the specific drugs for gray planthopper? Is there any good prevention and control method?

I. specific drug for gray planthopper

Single and compound agents such as pyrazidone, dimethyramine, pyrethrin and thiazide can be selected for control. Attention should be paid to the alternate use of drugs to delay the resistance of gray planthopper.

The rice seedling stage is the key period for the prevention and control of gray planthopper, so the prevention and control work should be done in time. In terms of control methods, the seedling fields which are not covered with anti-insect net and have a high number of insects should be controlled in time. Before transplanting seedlings, rice planthoppers of rice heavy weapon series are used to transplant with medicine. For the fields (including direct seeding rice fields) that have been transplanted with high number of insects, the medicine should be used immediately after turning green or after the seedlings are green.

Second, occurrence regularity

Except that there was no overwintering phenomenon in the southern rice area, most of the gray planthopper overwintered as 3-5-year-old nymphs in wheat fields, green manure fields, weed rhizosphere, under deciduous leaves and in soil crevices. When the temperature is higher than 5 ℃, it can climb to the host to feed, and the Eclosion begins when the average temperature in spring is about 10 ℃. When the temperature rises, the overwintering nymph looks for a suitable living place nearby, and generally moves to the wheat field to endanger. The adults of the overwintering generation are generally short-winged, living in weeds or wheat fields, and the nymphs of the first generation form the peak, while a small number of long-winged adults of the overwintering generation may migrate to the seedling field of double-cropping early rice.

III. Living habits

The population growth and decline of gray planthopper is mainly related to tillage and cultivation system, climate, natural enemies, host food conditions, artificial control and other factors. Grey planthopper usually has 5-6 generations in Jiangsu Province, which mainly overwinters as 3-4-year-old diapause nymphs on wheat and weeds, and propagates on wheat after spring. The adult period is from late May to mid-June. At this time, a large number of gray planthopper migrated from wheat fields and weeds to rice, forming the first transmission peak in seedling field and early planting field, and the first disease peak appeared in late June.

The nymphs of the second generation of gray planthopper hatched in the middle and last ten days of June formed the second peak of virus transmission in Honda, and the second peak of disease occurred in the middle and last ten days of July. the third and fourth peak of transmission will be formed when the climate is suitable, and there can be 2 or 4 peak in the field all the year round. Subsequently, the gray planthopper oversummered on Gramineae weeds, rice and other hosts in a very low number, and high temperature could cause diapause of the gray planthopper; when the weather was cool in late September, the fifth generation overwintered, and with the rice harvest in autumn, it was transferred to the nearby weeds or interplanted wheat seedlings to overwinter.

The control of gray planthopper can also be used in many ways, such as biological control and chemical control, and it is best to choose varieties with strong insect resistance.