In the process of soybean planting, soybean pests are extremely harmful to the high yield of soybeans, with many types and miscellaneous food, which is an important agricultural pest in China. So, what are the common soybean seedling insect pests? How to prevent it?
What are the insect pests at the seedling stage of soybeans?
1. Soybean root fly (soybean root maggot)
Also known as the bean root snake fly, Heilongjiang and Inner Mongolia suffer the most.
This insect is a monogamous pest that only harms soybeans and wild soybeans. Larvae are used to drill moths in the root cortex of soybean seedlings, and the affected roots become thicker, brownered or longitudinally lobed, deformed and hyperplasia or tumors.
In the mild victimization of soybeans, after the larva pupae, the root wound heals and the plant resumes growth, but the nodules are small and few, the top leaves are yellow, the pods are few, the yield is reduced, and the serious victims gradually die.
In addition, the larvae cause wounds in the roots, which can also cause root diseases, which aggravate the damage loss of soybeans.
2. Two leaf nails
Commonly known as ground trampoline, it is one of the common pests of soybeans, and the harm is becoming more and more serious.
Adult insects eat soybean cotyledons, true leaves, growth points and young stems at the seedling stage, and the affected leaves form small holes, and in severe cases, only leaf veins are left, which are network-like; in the flowering stage, the pistils that like flowers are caused to fall flowers, which reduces the number of soybean pods.
The larvae harm the nodules, affect the nitrogen fixation of the nodules and the growth of plants, and occur serious soybean nodules in the soil layer of 0 cm to 10 cm deep, almost all of which are eaten up, leaving only empty shells.
3. Underground pests
a. Grubs (females) can eat germinated seeds, bite off the rhizomes of seedlings, often causing seedlings to die, light seedlings are missing and ridges are broken, and heavy seeds are destroyed.
b. The scorpion (Lalagu) bites the newly germinated seeds, young roots and young stems of soybeans with adults or larvae, and cuts them into a mess and filament, causing poor growth and death of seedlings. In particular, the slugs crawl on the surface of the soil, scurrying back and forth, tunneling and crisscrossing, causing the seeds to be overhead, the seedlings to hang their roots, causing the seeds to fail to germinate, and the seedlings to lose water and die, and the loss is very serious.
c. Ground tigers (truncated insects) are an important class of underground pests.
1-2 instar larvae feed on the soil surface or the leaf back and leaf center of soybean; 2-3 instar larvae bite the leaves into countless small holes, some also endanger the growth point, after the 3rd instar into the soil, the night excavation bites off the whole seedling, dragged into the hole, often leaving a little leaf exposed on the soil surface, resulting in missing seedling ridges, and even destroying the seed replay in severe cases. Therefore, coating is an indispensable and important part of soybean cultivation.
Pest control methods at soybean seedling stage
At present, due to the fierce competition in the pesticide market, there are many varieties of seed coating agent manufacturers and different contents of different components, and the quality of seed coating agents varies greatly, and farmers must choose suitable, efficient and high-quality seed coating agents (encirclement and suppression + purity) when using seed coating agents.
1. Before sowing the crop, 3-4 kg/mu of 30 kg of 30 kg of octyl thiophosphorus granules are selected for hole application or ditch application.
2. Poisonous bait booby trap: If a serious field occurs against the ground tiger, 90% of the enemy insects can be sprayed 800 times on the green material (vegetables, broad-leaved grass) and sprinkled in the field to booby trap. For plots where tigers and caddisflies are serious, they can be booby-trapped with wheat, corn, wheat bran, etc. mixed with pallidum pesticides.
3. Medicament spray: For serious field plots of tigers on the ground, 20% anti-sweeping 1000 times liquid can be sprayed in the evening. During the peak spawning period of scarab beetles in July and August, it is optional to spray them on the surface with agents such as chlorpyrifos. For peanuts and other pest damage parts that are directly eaten, long-term residual agents cannot be used to irrigate the roots, so as to avoid pesticide residues exceeding the standard and even poisoning after human and animal consumption.
Source: China Pesticide Network