Does cotton bollworm affect Chinese cabbage yield? What pesticides can be used to eliminate it?

The growth and development period of Chinese cabbage is long, but the yield is high, and the demand for nutrients is large, but the root system of Chinese cabbage is shallow, and the absorption capacity is weak, so fertilizer and water should be continuously given during the growth and development period. Only many times the topdressing of fast-acting nitrogen fertilizer is to promote the growth of Chinese cabbage, to ensure the increase in yield of the ripe farmhouse fertilizer, or good effect of organic fertilizer, and the amount of organic fertilizer should be used according to the requirements of the fertilizer, the fertilizer can choose potassium sulfate compound fertilizer effect to plant Chinese cabbage, presumably rural people will plant. This is not about to reach the middle of the bush, "the first radish is the end", which means that it is the season to plant autumn cabbage again.

<>So what fertilizer is good for growing Chinese cabbage? How to grow Chinese cabbage well? Plum blossom to share their own practices with everyone.

Before planting, 1500-2000 kg of decomposed organic fertilizer (farmhouse fertilizer), 11-15 kg of urea, 50-80 kg of superphosphate, 20-30 kg of potassium sulfate or 30-50 kg of compound fertilizer with equivalent content were applied as base fertilizer. My Chinese cabbage is our common vegetable, and almost every household here grows some of it, especially in the north. Of course, Chinese cabbage in the growth process, fertilizer is also indispensable, only sufficient nutrients can make Chinese cabbage more high-yield, Chinese cabbage does not need too much nitrogen fertilizer, combined with the current situation of China's soil, China's soil nitrogen content exceeds the standard.

Therefore, we reduce the proportion of nitrogen fertilizer and increase the proportion of phosphorus and potassium fertilizer.

Planting Chinese cabbage generally uses rotten organic fertilizer as the base fertilizer, urea is one of the varieties growing at the seedling stage, Chinese cabbage not only has large leaves, but also has many leaves and a long growth period. Chinese cabbage life is divided into vegetative growth period and reproductive growth period, the former can be divided into germination period, seedling stage, rosette stage and ball setting stage, the latter is divided into moss extraction stage, flowering period and pod setting stage, because Chinese cabbage is rich in nutrition, excellent taste, high yield, storage and transportation, deeply loved by consumers and growers. However, in order to obtain high-yielding and high-quality Chinese cabbage, it is necessary to continuously improve and improve the cultivation technology of Chinese cabbage.

Chinese cabbage is the most susceptible to diseases before 6-7 leaves, and it is also an effective infectious period for aphid transmission. At the beginning of the diseased seedlings, the leaf veins of the heart leaves are translucent, and fade green along the leaf veins, and then there are mottled or flower leaves with dark and light green interspers, shrunken and deformed, and dark brown necrotic spots are sometimes produced on the petioles and leaf veins, and the severe diseased seedlings wilt and die. Viral diseases are mostly transmitted by aphids, and 50% anti-aphid wettable powder 2000-3000 times or 10% imidacloprid wettable powder 2000 times should be sprayed at the seedling stage to prevent aphids; At the beginning of the disease, spray 500 times of 20% virus A or 500 times of 5% bacterial poison water agent, spray once every 7-10 days, and spray 2 3 times in a row.

Common insect pests of Chinese cabbage mainly include: cotton bollworm, beet armyworm, cabbage worm, aphid, etc., in the prevention and control should be selected high-efficiency and low-toxicity pesticides, spray control in the young age of pests (before 3 instars), pay attention to the correct preparation of pesticide concentration, alternate rotation to reduce the generation of pest resistance, and improve the control effect.

In addition to harming cabbage, it also harms tomatoes, eggplants and other vegetables, and when vegetables are seriously damaged, the damage rate can reach 45%, and the yield can be reduced by 30%. On the 6th-8th day of the peak period of cotton bollworm eggs, Bacillus thuringiensis preparations can be sprayed, and at the peak of incubation to the peak of the 2nd instar, 30 75 ml of 10% cypermethrin EC can be used per mu, and 20-40 liters of water can be sprayed, and the validity period can reach 5-10 days, and each generation can be applied 1-2 times.

Investigation content and methods of vegetable cotton bollworm: (1) Adult insect trapping: 3 moths with a 20-watt black light lamp or sex pheromone trap from April 20 to August 31.

Yang Zhi recorded the number of males and females in the central and southern parts of the country from June 10 to July 30 day by day to determine the beginning, peak and end stages of moths.

2) Check eggs, larvae and natural enemies: When the first moth is lured by black light or poplar branches, sexual attractants, according to the occurrence period of the first to fourth generations of cotton bollworm in the past year, 2 representative tomato fields are selected and fixed-point plant survey is taken. When diagonally surveying the first generation of eggs, 10 plants per double row are 1 sample point, 50 plants are taken from 5 samples in each plot, and a total of 100 plants are taken in two plots, and when the second to fourth generations of eggs are investigated, 10 plants are taken in each double row of parallel lines, a total of 100 plants.

The whole plant was surveyed in one generation. In the second to fourth generation, only the number of eggs from the top of the plant to the upper part of the fifth compound leaf layer is checked, and the eggs are wiped out once every 2 days, and the damage is checked, and the eggs, larvae and natural enemies on the plant are counted, as well as the damaged plants and fruits.

3) Check the amount of residual insects: investigate the amount of residual insects in tomatoes, corn, sunflowers, cotton, bell peppers and other plots. The survey time is suitable for most larvae to enter more than 4 instars, as a reference for the next generation of insects.

The method of vegetable cotton bollworm: (1) the first generation of occurrence**: the occurrence period of the first generation of cotton bollworm, the degree of occurrence is closely related to the climate and wintering base in April and May, the general situation is that the temperature in April and May is high, the base is large, the occurrence period is early, and the occurrence is heavy, otherwise the occurrence is light and late.

2) The occurrence of the second generation**: The occurrence period**: the amount of overwintering moths induced by black lights and sexual attractants, the peak period of moths is counted, plus the calendar period required for the development of the whole generation of the first generation, and the peak period of the second generation of moths can be inferred with reference to historical data and meteorological conditions.

According to the larval age and the proportion of the instar stage surveyed in the main host field, plus the duration of late development and pupation, combined with the meteorological conditions, the peak period of the second generation of moths can be deduced again.

3) Section. The occurrence of the third and fourth generations**: the occurrence period of the **:

According to the beginning, peak and end stages of the previous generation of adult worms, the occurrence period of the next generation is carried out by the period distance method, or the data of the old mature larvae from field surveys, according to the proportion of different instars, plus the development period and meteorological conditions, the occurrence period of the next generation is determined. Occurrence of **: According to the larval density and natural enemies on the previous generation of host crops, combined with meteorological factors and historical data, a comprehensive analysis is carried out, especially pay attention to the rainfall, such as excessive rainfall in the rainy season, which will inhibit its occurrence, and drought at this time is conducive to its rampant occurrence.