What are the main cotton pests and diseases in summer and autumn?
What are the main cotton pests and diseases in summer and autumn? Please introduce the following: the main cotton pests and diseases in summer and autumn and their control methods: I. Pest and disease occurrence trends (1) Cotton mirids: moderate occurrence is expected during the flowering and boll-setting stage, and moderate to severe occurrence in cotton fields with vigorous late growth; the peak occurrence period is from late August to early September, with an affected area of 700,000 mu.
What are the main cotton pests and diseases in summer and autumn? Please introduce
The following introduces the main cotton pests and diseases in summer and autumn and their control methods:
I. Pest and disease occurrence trends
(1) Cotton mirids: moderate occurrence is expected during the flowering and boll-setting stage, and moderate to severe occurrence in cotton fields with vigorous late growth; the peak occurrence period is from late August to early September, with an affected area of 700,000 mu.
(2) Cotton thrips: moderate occurrence is expected during the flowering and boll-setting stage, with moderate to severe occurrence in some cotton areas; the peak occurrence is in mid-August, with an affected area of 650,000 mu.
(3) Tobacco cutworm: moderate occurrence of the fourth generation is expected; the peak of young larvae is in late August, with an affected area of 650,000 mu.
(4) Cotton spider mites: slight to moderate occurrence is expected during the flowering and boll-setting stage, with moderate occurrence in hilly cotton areas; the peak occurrence period is from late early August to mid-August, with an affected area of 450,000 mu.
(5) Cotton bollworm: slight to moderate occurrence of the fourth generation is expected; the peak egg-laying period is from August 13 to 20, with an affected area of 160,000 mu.
(6) Cotton aphids: slight to moderate occurrence of summer and autumn aphids is expected, with an affected area of 200,000 mu.
(7) Pink bollworm: light occurrence of the second and third generations is expected, with slight to moderate occurrence in non-Bt cotton and some cotton fields near villages, with an affected area of 80,000 mu.
(8) Fusarium wilt: as temperatures drop in late August, Fusarium wilt will show symptoms again in September; occurrence in old cotton areas will be moderate to severe, with an affected area of 450,000 mu, but the overall occurrence will be lighter than during the bud and flowering stage.
(9) Potassium deficiency physiological disorder: in recent years, it has occurred to some extent during the cotton growing period in our city. It began to occur in early June this year and reached its peak in mid-to-late June. Recent surveys show the incidence is lighter than the same period last year. All localities are urged to strengthen surveys.
(10) Cotton boll diseases: the occurrence of cotton boll diseases is closely related to rainfall amount and number of rainy days. In our city, the peak period for cotton boll diseases in normal years is from mid-August to early September. If rainfall is heavy and there are many rainy days during this period this year, it will favor the spread of cotton boll diseases.
II. Control recommendations
Based on the above analysis, the overall control strategy for cotton pests and diseases in our city in summer and autumn is: primarily control cotton mirids, cotton thrips, tobacco cutworms, and cotton spider mites and cotton bollworms in some cotton areas, while also controlling pink bollworm, cotton aphids, beet armyworm and other pests. Pay attention to the occurrence of cotton Fusarium wilt, potassium deficiency physiological disorder, and cotton boll diseases from mid-August to early September. Specific control measures are as follows:
1. Strengthen field management. In combination with fertilization, topping, removal of side shoots, and spraying mepiquat chloride and other measures in cotton areas, regulate the vegetative and reproductive growth of cotton plants, enhance their stress resistance, and reduce the number of cotton bollworm eggs and larvae.
2. Remove egg masses. Adult tobacco cutworms prefer to lay eggs on tall, dark green plants, with the highest number of eggs on the middle and upper parts of plants. Starting in early August, inspect cotton fields every other day in the morning or evening. When egg masses or clusters of newly hatched larvae are found, promptly carry them out of the field for disposal.
3. For cotton boll diseases, take measures such as timely clearing ditches and draining water, removing diseased bolls and spreading them out to dry, removing old yellow leaves from the middle and lower parts, and spraying appropriate pesticides for protection.
4. For potassium deficiency physiological disorder in cotton, adopt control measures based mainly on agricultural practices, with rational and timely fertilization and sufficient potassium fertilizer application.
5. Use chemical pesticides scientifically and rationally. In early August, primarily control the third generation of tobacco cutworm in some cotton areas, while also controlling cotton spider mites, pink bollworm and other pests; in mid-August, primarily control cotton thrips, cotton spider mites and cotton bollworm in some cotton fields, while also controlling cotton mirids, cotton aphids, pink bollworm and other pests; from late August to early September, primarily control cotton mirids and the fourth generation of tobacco cutworm, while also controlling cotton thrips, cotton spider mites, cotton aphids, pink bollworm and other pests. In control, adhere to the strategy of adapting measures to local conditions, providing classified guidance, controlling only when thresholds are reached, using pesticides scientifically, and giving full play to the pest-control role of natural enemies.
Control thresholds
Cotton spider mites: 15% of plants infested; cotton mirids: 3 insects per 100 plants; cotton bollworm: 10 young larvae per 100 plants; cotton aphids: 10,000 aphids on three leaves per 100 plants; tobacco cutworm: 1 cluster of newly hatched larvae per 100 plants, with spot treatment of larval clusters as the main approach, controlling before larvae disperse; cotton thrips: 20% damage rate on terminal buds. During control, pay attention to application quality, advocate alternating and rotating pesticides, and use power sprayers for spraying. Control in the afternoon after 4 p.m. is better. For older larvae, organize cotton farmers to handpick them in the early morning.
The following control pesticides are recommended: For cotton thrips and cotton aphids: choose acetamiprid and imidacloprid-type pesticides such as Aimeile, Yashijing, and Dagongchen, etc.;
Cotton mirids: fipronil (Regent), acephate, chlorpyrifos, beta-cypermethrin, etc.;
Cotton spider mites: Saomanjing, pyridaben, abamectin, propargite, abamectin·pyridaben, abamectin·diesel, etc.;
Cotton bollworm and tobacco cutworm: emamectin benzoate, tebufenozide, flufenoxuron, phoxim + pyrethroid pesticides, profenofos, etc.;
Cotton boll diseases: triadimefon, carbendazim, Lvbang 98, Junbike, Baoxianke, etc.
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