What are the integrated control techniques for cotton pests and diseases?
Topdressing is an important measure for cotton to set more bolls, set large bolls, reduce shedding, and increase yield. However, if topdressing is not done scientifically, it will not achieve the desired effect and sometimes may even produce side effects. In production, cotton topdressing has the following four key points. First, topdress according to the fertilizer requirement pattern. At different growth stages, cotton has different requirements for fertilizer...
In recent years, with the widespread planting of insect-resistant cotton, cotton aphids, cotton spider mites, Fusarium and Verticillium wilt, and cotton mirids have become the main pests and diseases in cotton fields, seriously affecting the improvement of cotton yield and quality. Cotton pests and diseases include the following aspects:I. Cotton seedling diseases: Pests and diseases at the cotton seedling stage are mainly damping-off and seedling blight. Factors such as low temperature at the seedling stage, abundant rain, continuous cropping, and too-early sowing are important reasons for the frequent occurrence of cotton seedling diseases. When cotton seedling root diseases first appear, promptly use 40% carbendazim suspension concentrate + 800-fold New High Lipid Film solution, 65% zineb wettable powder + 800-fold New High Lipid Film solution, or 36% Miankujing wettable powder 10-15 g/mu, diluted with 15 kg of water, and spray along the cotton seedling stems. At an interval of 5-7 days, spray once more.
II. Cotton aphid: Seedling aphids occur from emergence to after squaring. Control begins when the leaf curling rate reaches more than 30%. From mid-June to late July is the peak damage period for cotton aphids. You may choose 10% imidacloprid wettable powder + 800-fold New High Lipid Film solution or 15% Jinhaonian emulsifiable concentrate + 800-fold New High Lipid Film solution for uniform spraying of stems and leaves. When summer aphids occur during the bud and boll stage, because of high temperatures, you may choose 3% acetamiprid emulsifiable concentrate 2000-fold plus 40% chlorpyrifos 1200-fold + 800-fold New High Lipid Film solution to control aphids and other pests at the same time. After the cotton plants close rows, you may also use 80% dichlorvos emulsifiable concentrate + 800-fold New High Lipid Film solution and spray it between the cotton ridges on a sunny, windless evening. This is relatively effective against summer aphids and can also control cotton red spiders.
III. Cotton spider mite: It begins to appear in spots and patches in cotton fields in early May. At this time, temperatures are relatively low, reproduction is slow, the number of mites per leaf is relatively small, and damage to cotton seedlings is relatively light. From early June to late July, temperatures rise rapidly, cotton spider mites begin to reproduce in large numbers, and they cause concentrated damage; in dry years, damage is rampant. You may choose 15% Saochongmanjing emulsifiable concentrate + 800-fold New High Lipid Film solution, or 1.8% abamectin + 800-fold New High Lipid Film solution for spray control.
IV. Cotton mirid: In recent years, damage by cotton mirids to cotton has worsened year by year. The period for chemical control is mid-to-late June. During this period, cotton plants are relatively tender. If there is abundant rain, and the relative humidity in the cotton field is high, the climatic conditions are favorable for cotton mirid damage. This period is the key period for control. At the cotton bud stage and boll stage, you may choose 5% acetamiprid emulsifiable concentrate + 800-fold New High Lipid Film solution or 4.5% beta-cypermethrin emulsifiable concentrate + 800-fold New High Lipid Film solution for spray control. The effect is relatively good, and it also controls cotton bollworm.
V. Cotton bollworm: It is the main pest during the cotton bud and boll stage and generally occurs in four generations a year. It mainly damages cotton in the second and third generations, with larvae boring into and feeding on buds, flowers, and bolls as the main form of damage. Borer-damaged cotton bolls easily rot and fall off or become stiff segments. Integrated control methods may be adopted. 1. Physical control: Install Jiaduo frequency-vibration insect-killing lamps in concentrated cotton planting areas, equipped at one set per 60 mu; use over contiguous areas for a better effect. 2. Chemical control: You may choose 90% methomyl wettable powder + 800-fold New High Lipid Film solution, 4.5% beta-cypermethrin emulsifiable concentrate + 800-fold New High Lipid Film solution, or 1.8% abamectin + 800-fold New High Lipid Film solution for stem and leaf spraying, once every 7 days, for 2-3 consecutive sprays. For later residual control, you may use 20% Xinmie emulsifiable concentrate + 800-fold New High Lipid Film solution or 20% cyanophos-malathion emulsifiable concentrate 1500-fold for uniform spraying.
VI. Cotton Fusarium wilt and Verticillium wilt: Both are diseases that harm the vascular bundle tissues of cotton, causing symptoms such as leaf discoloration, drying, shedding, and wilting. In severe cases, plants die in contiguous patches, seriously affecting yield. At the cotton bud stage, Kuhuangweiling may be used at 40 g per mu diluted with water for spraying (preferably spraying combined with drenching) 3-4 times.
VII. Beet armyworm: It is an omnivorous pest and occurs in 4-5 generations a year, with severe overlapping of generations and uneven larval instars. High-temperature and dry climatic factors and cultivation conditions with multiple crops mixed together are favorable for the occurrence of beet armyworm. Generally, cotton fields with extensive management and many weeds have more severe occurrence. You may choose 0.2% emamectin benzoate + 800-fold New High Lipid Film solution or 25% diflubenzuron suspension concentrate + 800-fold New High Lipid Film solution and spray evenly on cotton plants and field weeds, for 2-3 consecutive sprays; the effect is relatively good.