Common diseases and insect pests of soybean and their control techniques

(Agricultural Wealth Network) In recent years, soybean diseases and insect pests often occur, affecting the yield and quality of soybean. Soybean is damaged by many pests during its growth period, resulting in yield reduction and quality decline affecting yield. The damage characteristics and control techniques of several pests are described as follows.

1. The bean moth is commonly known as bean worm (motherworm), which damages soybean leaves with larvae, causing nicks or holes, eating into meshes in light cases, and eating into bare beans in heavy cases, which cannot bear pods and affect yield. Generally, from the middle and late July to the first ten days of August is the peak period of adult oviposition, from the late July to the late August is the peak period of larval occurrence, the newly hatched larvae have backlight, latent leaf back during the day, the first instar to the second instar bite the top leaf edge into a notch, generally do not migrate, the third instar to the fourth instar eat greatly that is to turn the plant damage, this is the appropriate period for control, the fifth instar is the gluttony stage, accounting for about 90% of the larval food intake. 6-8 month, rain coordination, is conducive to the occurrence of bean moth, soybean plants grow dense, low-lying fertile soybean fields, bean moth adults lay eggs more, harm heavy.

Control method: Spray 50% phoxim emulsion 1000 times or 20% fenvalerate 2000 times, or 20% fenvalerate EC or 2.5% cymethrin EC 2000 times, spray 50kg/mu at the larva stage before the third instar.

2. There are many species of soybean bridgeworm, most of which are Spodoptera argentea. Larvae damage bean leaves, eating damage tender tips, flowers and young pods, can eat up leaves caused by flower drop pods, seeds are not full, seriously affecting yield. The bridge-building insect can occur for many generations every year, especially from mid-July to mid-August. Adults day out night, phototaxis strong, like to lay eggs in the dense growth of bean fields, eggs scattered in the upper leaves of bean plants. Larvae when young only mesophagous, leaving the epidermis was fenestrated. The instar larvae feed on the upper tender leaves and form holes, mostly at night.

Control methods: available 20% fenvalerate EC or 2.5% cypermethrin EC 2 000 times solution, 40 kg spray per mu.

3. Weevils Weevils eat plant stems and leaves.

Control method: 50% phoxim emulsifiable concentrate 1500-2000 times solution or 20% fenvalerate 2000 times solution evenly sprayed.

4. Soybean pod borer Soybean pod borer is also called soybean pod borer. It eats pods with larvae. Before the larvae eat, they are covered with a white silk net. Generally, they bite into the pods from the seams. The damaged beans bite into channels or broken shapes.

Control method: 10% cypermethrin emulsifiable concentrate, mu with 35-45 ml, or enemy kill emulsifiable concentrate, active ingredient 0.5-1 g, mixed with water 40 kg evenly sprayed.

5. Soybean aphids damage from seedling stage, feeding on growing points, tender leaves, tender stems and tender pods of plants, spreading virus, causing leaves to shrink, growth slowed down, pod number reduced, serious occurrence at seedling stage can cause whole plant death.

Control method: 50% phoxim emulsifiable concentrate 1500-2000 times solution or 20% fenvalerate 2000 times solution evenly sprayed.