With the development of economic transformation and development, the cotton planting area has been decreasing, and the traditional commodity cotton base has been affected. In this paper, the causes and insect habits of common diseases in cotton are analyzed, and the control technologies of common diseases and insect pests of cotton are elaborated from three aspects: agriculture, biology and chemistry, and some feasible technologies and methods are provided, which have a certain reference effect.
<h1 class="pgc-h-arrow-right" >1 Analysis of common diseases and pests of cotton</h1>
1.1 Common diseases are
Cotton seedling blight, cotton seedling anthrax, cotton blight, cotton verticillium wilt disease and other cotton seedling blight is a disease that often occurs in the cotton seedling stage, mainly in the cotton nursery bed and open field direct field, which can cause the seedbed into pond dead seedlings and field lack of seedlings and ridges, affecting the whole seedling. The main conditions of the disease are the climatic conditions before and after the emergence of cotton seedlings, especially the soil temperature and wet soil in the sowing layer, and low temperature and high humidity are conducive to the growth and infection of pathogens.
Cotton seedling anthrax is a disease that can occur during the entire growth period, and it is seriously harmful at the seedling stage and the bell stage, and the general incidence rate of the seedling stage is 20%-70%. The occurrence of diseases is closely related to temperature and humidity, and low temperature and rainy diseases occur seriously. Poor seed quality, sowing too early, too deep, and continuous cropping in cotton fields for many years can aggravate the occurrence of diseases.
Cotton blight can occur from the seedling stage to the bell stage, once it occurs is difficult to cure, there is "cancer", the victim cotton field generally reduced production by 30%-50%. Most of them are mixed with cotton blight and verticillium wilt. The occurrence of diseases is related to the pathogenicity of the bacteria themselves and the number of pathogens in the soil, and is related to the environment such as cotton varieties, climate and farming and cultivation.
Cotton verticillium wilt mainly occurs in the adult stage, transmission and invasion are basically the same as cotton blight, the field is often mixed with cotton blight, and the yield of diseased plants is generally reduced by 10%-30%. Temperature has a greater impact on the disease, the appropriate temperature for the disease is 25 ° C -28 ° C, at the appropriate temperature, rainy will aggravate the occurrence of the disease.
1.2 Common insect pests are: cotton bollworm, corn borer, cotton blind bug, cotton field tobacco whitefly and so on
Cotton bollworms have a complex diet, except for cotton, they eat corn, soybeans, etc. The larvae harm buds, flowers and bells, causing shedding and rotten bells, and the prevention and control is not timely, and the budbell shedding rate can reach more than 50%. The larvae overwinter in the soil pupae, and the adults lie down at night and have strong flying power, and have a tendency to high-pressure mercury lamps and frequency vibration lamps, and to poplar trees, acacia and other branches and leaves.
The corn borer is a multi-food pest that harms more than 70 host plants, including cotton, corn and sorghum. It generally occurs in 3-4 generations, with old mature larvae overwintering in corn stalks, cotton stalks, etc. Mothing at the base of the petiole or at the buds of the lower or upper leaves of the tender head causes the young head and leaves to wither, and the larvae also harm the green bell. In case of strong winds, the upper part of the cotton plant is easy to break.
Cotton blind bug is a general term for the blind bugs that harm cotton, mainly green blind bugs and medium black blind bugs. Overwintering with eggs, green blind bugs are under the epidermis of overwintering hosts such as broad beans, as well as in the tissues of weed hosts.
Cotton field tobacco whitefly is an exotic pest, wintering in greenhouses, strong reproductive ability, few effective prevention and control agents, and great harm to greenhouse vegetables. The harm to the cotton field is 4-5 months, breeding 5-6 generations, the generation overlap is obvious, generally entering the cotton field in June, the peak period of July to September, and comprehensive technical measures are needed to control.
<h1 class= "pgc-h-arrow-right" >2 Common pest control measures in cotton</h1>
2.1 By selecting excellent varieties
Before planting agricultural measures such as scientific cultivation management to improve their ability to resist diseases and insects, it is necessary to select suitable disease- and insect-resistant varieties according to the actual situation in the region, which can effectively reduce the occurrence of diseases and insect pests such as cotton bollworm, cotton seedling anthrax, cotton blight and cotton verticillium wilt, and at the same time can play a certain role in resisting other diseases and insect pests.
2.2 Physical biological control technology is an effective method for the control of cotton pests and diseases
In the process of cotton pest control, the phototropism and chemotaxis characteristics of harmful insects can be used to rationally use physical equipment such as insecticidal lamps, black lights and silver-gray film to trap and kill pests. In addition, the use of poplar branches to trap moths and other methods in cotton fields to control harmful insects by using their life cycle and hobby habits is achieved. By releasing a large number of natural enemies in the cotton planting area during the spawning and breeding period of harmful insects such as cotton bollworms and corn borers, the existing physical control methods are supplemented and the disadvantages of limited physical control technology are reduced.
2.3 Scientific use of medicine is the key to ensuring the yield and quality of cotton
The use of modern technology is an important means of comprehensive control of cotton diseases and insect pests. In the use of pesticides, it is necessary to fully grasp the differences in various cotton areas, effectively control the dosage of drug control according to the local cotton growth environment, climatic conditions and the degree of occurrence of diseases and insect pests, and adjust the prevention and control measures in a timely manner when the disease and insect conditions change. In chemical control, it is necessary to fully grasp the principle of early control and spray the drug before the eggs hatch into adults.
< h1 class="pgc-h-arrow-right" > 3 concluding remarks</h1>
Cotton planting pest control is a comprehensive work, can not rely on only one technology to complete, the use of agriculture, biology, chemistry and other technical measures for integrated control.