How to control the third and fourth generations of cotton bollworm in cotton fields

In the Huanghuai region of China, from the middle of July to the beginning of September, the third and fourth generations of cotton bollworms are endangered. Due to the increase in the percentage of interplanted cotton fields and the late development of this year, the second generation of Helicoverpa armigera has a larger amount of debris, and more rainfall in July and August. In addition, the insect-resistant performance of insect-resistant cotton in the middle and late stages is greatly reduced. According to the above analysis, in the Huanghuai region this year, the third and fourth generations of Helicoverpa armigera will occur moderately and occur in large numbers. From the author for many years to view: Therefore, most of the pure cotton plants have been aging, cotton bollworm eggs off the amount of hatching is also relatively low; and interplanting cotton fields, most of the later maturation, cotton plants younger, It is very beneficial to the feeding of cotton bollworm, so the amount of eggs laid and the hatching rate of eggs are 45.2% and 53.6% higher than that of pure cotton fields. Under the condition of non-control, the damage rate of the budding bolls of interplanting cotton is 56.8% higher than that of pure cotton. Therefore, late-maturing cotton fields (most interplanting cotton fields and a few late-spring pure cotton fields) are the focus of the third and fourth generations of cotton bollworms. Therefore, prevention and control of the third and fourth generations of cotton bollworms require comprehensive prevention and control.

The first to promote the use of poplar twigs for trapping Helicoverpa armigera adult worms according to acid, sweet, scent and other substances has a strong chemotaxis characteristics, in the emergence stage of cotton bollworm, poplar branches to the moth has a good effect. The fresh poplar branches with leaves will be bundled into one handful every 6-8 sticks. About two meters high will be inserted into the cotton field in the evening and 10-15 per mu. When the adults of the cotton bollworm come out at night and smell the odor emitted by the poplar branch, they drill into the branch. Starting from the second day after the insertion, before each day of dawn, before the sun appeared, the branch took a set of plastic belts and pulled it out to shake it, collecting and hiding the moths for killing. After the killing, place the branches on the cotton line to prevent the sun from shining, and then insert the sticks at dusk. Change every 5-6 days and keep it until the end of August.

The second is to spray calcium superphosphate solution to drive the spawning of cotton bollworm, which can greatly reduce the control area. As the cotton tip exudates oxalate, it will lure the bollworm to lay eggs. According to this, in the spawning period of cotton bollworm, add 1%-2% superphosphate soaking clarifier in insecticide solution, spray evenly after mixing with pesticides, and spray 6 lines each at intervals of 4 lines, per acre. Each time the mixture is sprayed with 50-70 kilograms of liquid, the clear liquid soaked with superphosphate can also be sprayed separately. The insect repellent has the same effect. Superphosphate can also harden the eggshell of the bollworm, causing the larvae to die without shelling.

The third method is artificial ovulation and insecticide. Because the older larvae of the cotton bollworm have stronger resistance to drugs, the drug killing effect is poor. Two days after spraying, combined with field management, the larvae in the morning and rainy days are used to carry out activities. Manual capture. Put the top, side, branch and ineffective buds out of the plot to compost or deep-buried plots, which can reduce field eggs by 12% to 24.5%, insects by 26% to 42%, and avalanche damage by 37%.

The fourth option is to use pesticides on the road to prevent and control the use of the above-mentioned control measures. At the same time, field investigations should be conducted. If the third generation of cotton bollworms reaches 15 larvae and the fourth generation of cotton bollworm larvae reaches 8-10, it is necessary to Timely spraying control. At present, the following pesticides with good control effect can be selected: spray 1000 times of 25% diafenthioni EC, or 1000-1500 times of 35% EC, or 1500 times of 20% methomyl EC, or 2.5% of CIPP. 1500 times, or 2.5%, 1500 times that of EC, or 10% of 2000 times. These pesticides have good control effects on many species of insect pests, such as Helicoverpa armigera, Blind mite, locust, red spider, corn borer, and bridge worm.

The fifth method to improve the spraying method is that the third and fourth generations of cotton bollworms have a long spawning period. The cotton plants are relatively tall and scattered. In addition, the eggs and larvae of the third and fourth generations of cotton bollworms are staggered and overlapped. In the year of major occurrence, multiple sprayings are required. If the conventional large-volume method is used for spraying, not only the work efficiency is low and the labor intensity is high, but also the adhesion and penetration of the liquid are poor, and the spraying effect is often not good. It is necessary to actively promote the use of neutral detergent powders in liquid medicines and small-volume sprays with high efficacy, low labor intensity, and good control effects.

Calf Growth Products

Tangshan Finely Animal Care Co.,Ltd ,

Posted on