Cotton blight, farmers friends habitually call it "cancer", any field where the disease has occurred, and then cotton is often easy to show "cancer", even more serious year after year, this is because of such bacteria Once buried in the soil, it is difficult to eradicate, and it is easy to relapse when it encounters suitable climatic conditions.

In recent years, a number of insect-resistant cotton varieties have been introduced and selected in China. The insect-resistant and high-yield varieties are good. In the normal climate, the yield-increasing advantages of insect-resistant cotton varieties are also significant. However, the weakness of insect-resistant cotton is that there is some deficiency in disease resistance. When it was in the unfavorable climate of continuous rainy weather from early June to early July, some insect-resistant cotton was even seriously ill. Among them, some insect-resistant cotton varieties have a susceptibility rate of about 40%. Although they are resistant to insects, they will still reduce production. At the same time, most of the insect-resistant cotton varieties are concentrated on the peach, and the early stage is prone to premature aging, and the production also deserves special attention.

For the "cancer" of cotton, in addition to using disease-resistant varieties to enhance disease resistance, according to my experience in multi-point surveys, improving water system facilities and improving fertilization techniques can enhance disease resistance.

First, increase the application of various types of organic fertilizer. I have applied bio-organic compound fertilizer to cotton fields with about 20% of the cotton wilt disease strains. The disease strain of the year was reduced to 5%, which was lower than that of the adjacent cotton-like susceptible strains without the application of bio-organic compound fertilizer. About a percentage point. This is because the secretion of bio-organic fertilizer can inhibit the proliferation of germs. Therefore, one can apply 3000~4000 kg of organic fertilizer produced by the farmer per mu; secondly, bio-organic compound fertilizer with different strains can be applied, about 75 kg per mu; three can apply high-energy organic compound fertilizer, about 100 kg per mu. All localities can be flexibly selected according to the actual situation in the local area.

Second, increase the amount of potassium fertilizer. Cotton, peanuts years of production practice shows that the demand for potash conventional cotton is relatively less than cotton, cotton now occupies a large market share, while cotton on potash requirements than conventional cotton more than double . Potassium deficiency in the field of planting insect-resistant cotton is common. Increasing the application of potassium fertilizer can not only enhance the defense ability against Fusarium wilt, but also prevent physiological diseases (bleeds) caused by potassium deficiency and the high temperature and frequent explosion after heavy rain. Red leaf stem blight can also avoid premature aging. Generally, potassium fertilizer is applied to not less than 30 kg per mu.

Third, heavy application of flower ring fertilizer, peach fertilizer. When cotton enters the flowering and bolling period, it is the peak period of fertilizer demand. About 20 kg of multi-component compound fertilizer should be applied per mu. When there are 3 or so peaches per plant, about 15 kg of urea should be applied per mu. At the same time, spraying potassium dihydrogen phosphate, selebrex boron, etc. outside the root can effectively prevent the cotton from premature aging.

Fourth, improve the water system facilities. In the years when blight disease is severe, we often see in the field investigation that in the same cotton field where blight is likely to occur, the high groundwater level is much higher than the groundwater level, indicating that the root system is poorly developed. Cotton's ability to resist the invasion of Fusarium oxysporum is weakened. Cotton seedlings first hair roots, cotton field water system facilities are good or bad, it is related to the strength of cotton roots, hair roots good cotton, can also enhance resistance to blight. Therefore, high-yield cotton fields should be connected to the drainage ditch, the trench and the gutter. The heavy rain of 100 mm per day can discharge, reduce energy, filter, and rain in the fields.