Analysis of Cotton Bud and Boll drop

A large number of buds and bolls often fall off in cotton production, which seriously affects cotton yield and cotton farmers 'income. Because of the various causes of bud and boll dropping, only symptomatic treatment can effectively reduce bud and boll dropping and improve yield and benefit.

1. Variety factor. Blind stink bugs and cotton bollworms like to lay eggs on cotton varieties with more hairs, and more hairy varieties increase the adhesion of eggs, which are not easy to be washed off by wind and rain, so they are seriously affected, resulting in a large number of bolls falling off. The number of damaged buds and bolls of smooth leaf varieties was 40.3% less than that of hairy varieties.

2. Cultivation factors. At present, cotton production is a very prominent problem is too high density, easy to cause a large number of buds and bolls drop. At the same time, too high density often causes chain reactions such as aggravation of diseases and insect pests, serious premature aging in late stage, etc.

Third, fertilizer factors. Mainly because of improper fertilization, potassium deficiency, boron deficiency, molybdenum deficiency and other factors caused.

IV. Pest factors. In addition to cotton bollworm caused by bud drop, there are cotton stink bug, cotton weevil can directly damage caused by bud drop. Cotton aphids, red spiders, whiteflies and other indirect damage can also be caused by plant malnutrition caused by the loss of buds and bolls.

5. Disease factors. The occurrence of diseases such as Fusarium wilt, Verticillium wilt and red leaf stem blight (especially under high humidity conditions) often leads to a large number of buds and bolls falling off.

VI. Chemical control factors. Many cotton farmers wait until the cotton grows vigorously before chemical control, resulting in imbalance between vegetative growth and reproductive growth of cotton plants, elongation of fruit nodes, unsatisfactory plant shape, serious loss of buds and bolls, and induced premature senescence (Note: some cotton farmers adopt products called "eight no matter" on the market, due to low content of contraction node safety, can not achieve chemical control effect, resulting in plant flourishing).

7. Climatic factors. Drought, high humidity, high temperature, insufficient light will lead to the loss of buds and bolls.

8. Physiological factors. 1. No fertilization. When flowering, encounter rainfall, high temperature, high humidity, drought and other adverse environmental conditions, will destroy pollen and pollination, fertilization process, so that the ovary can not be fertilized and shed. 2. Effects of hormones in cotton plants. Cotton bolls contain endogenous hormones such as abscisic acid and ethylene. The abscisic acid content increases greatly at 3 days after flowering and reaches the peak at 10 days after flowering, so the number of bolls dropped at this time is the most, and then it decreases significantly. Ethylene peaks on the day of flowering and 1~2 days before boll opening. In the early stage, it often causes young bolls to drop, and in the later stage, it promotes cotton bolls to mature.

Based on the above reasons, the following preventive measures are recommended:

1. Smooth leaf varieties with many buds and strong boll setting should be selected, and hairy varieties should not be planted as much as possible.

Second, blindly rely on increasing density to get yield is not desirable, must be based on the soil fertility level and the characteristics of the varieties planted, to achieve reasonable sparse planting.

Third, the base fertilizer should be formulated according to the characteristics of cotton fertilizer requirements. Base fertilizer with diammonium phosphate potassium fertilizer is good, conditional as much as possible with organic fertilizer.

Fourth, topdressing should be based on nitrogen fertilizer, to "light bud stage, heavy boll stage"(potassium deficiency in bud stage, phosphorus deficiency in flower boll stage). Note that topdressing nitrogen fertilizer should avoid rainfall and stay away from cotton roots according to weather forecast, and water in time after topdressing.

5. Chemical control shall be carried out by reducing safety (auxiliary element), so as to achieve "a small number of times, light control and frequent adjustment".

VI. Carefully check diseases and insect pests frequently, and timely apply drugs for prevention and control at the initial stage of occurrence. At the same time, it should be noted that spraying should be carried out after 5 p.m. to prevent pollen grain breakage and abortion caused by chemical solution in the peak period of pollinating in the morning and affecting normal pollinating.

7. In case of high temperature and drought, water in time.

8. When encountering bad weather conditions such as rainy and light shortage or high temperature and drought, combined with pest control or disease prevention, brassinolide (or 0.01% gibberellin)+0.1% boron fertilizer +0.1% 25% complex high zinc +600 times 40% chelated high potassium (or 0.5% potassium dihydrogen phosphate) with high quality can obviously reduce bud and boll shedding and significantly increase yield.

9. Spraying 300~400 times solution of 20% Baoying (phenylamino acid) once at full bloom and flower boll stage can play a good role in keeping buds and bolls.