Control techniques of soybean aphids

Soybean aphids belong to the family Homoptera, which is the main pest in soybean producing areas of Huachuan County. The occurrence period of soybean aphids has been advanced in the past two years, and the damage has also been aggravated. Soybean aphids tend to tender. soybean aphids concentrate on the top leaves, tender leaves and tender stems of the plant with adults and nymphs, which can not only cover the stems and leaves, but also damage the tender pods. When the plant was seriously damaged, the leaves curled, the root system was stunted and yellowed, the plant was short, the branches and pods decreased, and the 1000-grain weight decreased. If there is no timely prevention and control at the seedling stage, the light cases will be reduced by 20% to 30%, and the heavy ones will be reduced by more than 50%. Soybean aphids can also spread soybean mosaic virus disease. The insect began to appear in the soybean field in the middle and late June, and the damage was serious during high temperature and drought.

Morphological characteristics

Winged viviparous female aphids, ovoid, yellow or yellowish brown. The wingless female aphid is long oval, yellow or yellowish green, and the antennae are shorter than the body.

Life habits: soybean aphids occur for about 10 generations a year in Huachuan County, overwintering with eggs on plum branches. In the spring of the second year, when the average temperature was above 10 degrees, the winged parthenogenetic aphid began to migrate to the soybean field to damage the seedlings, and entered the peak period from late June to mid-July, and the light yellow small soybean aphid appeared in late July. The number of aphids began to decrease, and the air temperature decreased from late August to early September, and the soybean aphid entered the late breeding stage. From late June to early July, the average temperature reached 25 ℃ and the relative humidity was less than 70%, which was beneficial to the occurrence of aphids.

Prevention and cure measures

When soybean aphids occur, 5% to 10% of plants curl leaves in the field, or when the rate of aphids is more than 50%, and the number of 100 aphids is more than 1500, it can be sprayed for control.

1. Choose insecticides with high efficiency and low toxicity. In the past, farmers used to use organophosphorus pesticides such as omethoate and dimethoate, or pyrethroids such as cypermethrin and kung fu, when controlling aphids. In view of the high toxicity and high resistance of organophosphorus pesticides, it is suggested that the townships (towns) should choose the following pesticides when guiding farmers to carry out the control of soybean aphids:

(1) 3% acetamiprid (Mobilang, Golden Century, Adak, etc.) EC, 15,20ml per mu. According to the experiment and demonstration in the past two years, 3% acetamiprid EC has the advantages of good control effect, long effective period, high safety and red spider control, and can be used as the first choice for aphid control at present.

(2) the dosage of 10% 11 is 30 ml per mu than that of chlorhexidine.

(3) 25% Huifeng Kuaike EC or 25% Kuaishaling EC, 30 ml per mu.

(4) in the plots where red spiders occur at the same time, the above chemicals can also be mixed with 1.8% avermectin (parasite, acaridin, alfudine, 20 ml per mu) to control red spiders.

2. Prohibit high toxic and high residual agents, such as omethoate, methamidophos, methamidophos and so on.

3. In the soybean field which has been covered with ridges, it is recommended to use sprayer.