The common pests and diseases of cotton are mainly verticillium wilt, blind mites and cotton aphid. The prevention and treatment methods are described below.
Verticillium wilt: prevention is the key
Verticillium wilt is known as cotton "cancer" because of its rapid occurrence, serious loss, and difficult control. Prevention and treatment of the disease should be based on strengthening field management. Through the selection of resistant varieties, application of base fertilizer, early film removal, early refining, early tube cultivation and other measures to improve the disease resistance of cotton seedlings, preventive use of drugs, timely control The condition, especially after the rain, should be used immediately to prevent the disease from spreading. The drug may be selected from trichloroisocyanuric acid or allicin, once every 7 to 10 days, and continuously controlled 2 to 3 times.
Blind elephant: seize the three key periods of medication
Blind elephants occur 5 to 6 generations a year, the harm is widespread and serious, and prevention and control must seize three key periods. The first period is mid-to-late May, when there are 4 to 5 leaves of cotton seedlings, this is the peak period of hatching of a generation of nymphs. When the rate of damaged plants in the field is 1% to 2% or 100 plants have 1 or 2 insects. Start taking the medicine and focus on the insect source field. The second period is in mid-June, when the cotton seedlings enter the bud stage. At this time, it is the peak period of the second-generation nymph hatching. It is used when the rate of new infected plants is more than 5% or that there are 5 to 10 insects in 100 plants. The third period is from the end of June to the beginning of July, when the three generations of nymphs hatch. The generation of the second generation and the second generation of blind scorpion is concentrated. As long as the medicine is used in time, the control effect is good. After three generations, the generations overlap, and the cotton grows vigorously and the field is sullen. The control is difficult and the effect is obviously reduced. In the prevention and control of blindness, it is necessary to mix and match drugs with different insecticidal mechanisms, such as the combination of strong contact drugs and drugs with strong systemic or fumigation effects. Usually use 4.5% beta-cypermethrin EC in 20ml plus 40% chlorpyrifos EC 50ml, or 20% high-chlorine horse EC 75-100亳, or 40% omethoate 50ml plus 4.5% beta-cypermethrin EC 20L , add water spray. Try to apply the medicine around 10 am or 5 pm. At this time, the blind mites are more active, mostly distributed in the young parts of cotton plants, and the control effect is obvious. When spraying, first hit the outside, turn to the circle to play in, focus on annihilation, to prevent the migration of blind elephants leading to reduced effectiveness.
Cotton aphid: good effect of alternating medication
Cotton aphid can be divided into nursery and Fuxi in the cotton field according to the time of occurrence. The nursery occurs in the environment before the emergence of the seedlings to the buds, and adapts to the low temperature environment. Fuxi mainly occurs in the middle to late July to August, and adapts to the environment with high temperature. The cotton aphid has a rapid reproduction speed and a large number. The cotton farmers have often reported poor drug use in production. This is mainly caused by a single drug variety, insufficient water consumption, and uneven application. Suitable drugs for controlling cotton aphid include imidacloprid, omethoate, acetamiprid, pymetrozine, and nitenpyram. Pay attention to the alternate rotation of drugs, and increase the water consumption appropriately. The water consumption per mu is 50-60 kg. When spraying, spray the spray on the front and back of the plant and the front and back of the blade.
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