Key Points for Disinfection and Weed Control in Cotton Seedling Raising

Recently, a farmer from Shuqiao Village, Wuluo Town, Yunmeng County, Hubei Province, called to ask about pesticide use on cotton. Here, in response to two issues farmers care about in cotton seedling raising, I will discuss the precautions for pesticide application for prevention and control.

First, does the seedbed soil still need to be disinfected when raising seedlings from coated cotton seed? At present, most of the seed used in China's cotton production is cottonseed that has been delinted with foamed acid and then treated with a coating agent; this is referred to as coated cotton seed. The chemicals in the coating agent can kill pathogens attached to the cottonseed, but the various soilborne pathogens lurking in the soil still need to be killed or suppressed with fungicides. If this step is neglected, even very good cotton seedlings may become infected with seedling-stage diseases such as damping-off, anthracnose and stem blight. Therefore, when preparing cotton nutrient-cup seedbeds, pesticides should still be applied to the seedbed soil to prevent disease. Many chemicals can be used, such as 25% carbendazim at 1200-1500 times dilution, 2.5% Celest seed dressing at 500 times dilution, or 25% Xinxiu (propiconazole) emulsifiable concentrate 5 ml and 60% Baitai water-dispersible granules 8 g each mixed with 30 jin of clean water, sprayed on the seedbed soil before making the cups so that the solution penetrates all the cup soil. After the cotton seedlings have emerged completely, pesticide should also be sprayed promptly to prevent invasion by external pathogens. Suitable sprays include 1:2:200 Bordeaux mixture or 0.01% Baoliang, etc.

Second, can herbicides be applied on cotton nutrient-cup seedbeds? Weed damage is a common problem in cotton nutrient-cup seedling raising, and sometimes weeds can cause seedling smothering, severely inhibiting the growth and development of cotton seedlings. Severe weed infestation on seedbeds is often caused by two reasons: first, a newly selected seedbed site where there was no time to plow and bake the soil, so the weeds were not subjected to winter freezing, spring sun-drying and thorough hoeing, leaving residual weeds to propagate; second, the application of farmyard manure that was not thoroughly decomposed, so weed seeds were brought into the seedbed and multiplied rapidly. Therefore, herbicides should be applied after cotton sowing and before emergence. First, you can choose 48% Lasso emulsifiable concentrate at 150-200 ml per mu, or 72% Dual emulsifiable concentrate at 150 ml per mu, each mixed with 60-80 jin of clean water for spraying. Second, you can choose 23% Chuangcaojing emulsifiable concentrate at 100-120 ml per mu mixed with 80 jin of water for spraying, which can effectively prevent weed damage.