It's the right time to control cotton summer aphids, growers should not miss the opportunity
It's the right time to control cotton summer aphids
(Agricultural Wealth Network) Every year from late July to early-to-mid August is the period of heavy occurrence of cotton summer aphids. Aphids are divided into seedling aphids and summer aphids, which are two ecotypes of the cotton aphid that have differentiated to adapt to different environmental conditions. They mainly gather on the underside of cotton leaves or on tender tips to suck sap. In the cotton region of the Yellow River basin, summer aphids mainly occur from mid-July to mid-August, and can cause the upper tender leaves of cotton to curl, the middle leaves to develop oily patches, and in severe cases lead to shedding of squares and bolls. Because when summer aphids occur, cotton has mostly closed its rows, with many leaves and dense branches, many farmers report that summer aphids are harder to control than seedling aphids.
I. Occurrence situation
At present, cotton summer aphids are widespread in Hengshui City, with heavy damage in some plots. In Wuyi County, the number of aphids on three leaves per 100 plants is 3000-5000, with a maximum of more than 20,000, and severe leaf curling has occurred; in Gucheng, the highest plot had more than 10,000 aphids on three leaves per 100 plants, with a leaf-curling plant rate of 36%. The meteorological department predicts that in July our city will still maintain high-temperature weather, with precipitation close to normal years; hot, humid weather with alternating sunshine and rain favors the occurrence of cotton summer aphids. Here we remind the broad community of farmers to closely strengthen field observation, apply pesticides scientifically and promptly, and reduce the yield loss caused by cotton aphids to a minimum. The field chemical control methods for cotton aphids are provided below:
II. Control methods
1. Rotate the pesticides used. Rotate field conventional pesticides such as acetamiprid, imidacloprid, and chlorpyrifos to reduce the likelihood of aphids developing resistance; once aphids develop resistance to a certain chemical pesticide, even increasing the number of applications and increasing the pesticide concentration will not achieve the ideal control effect.
2. Spray the occurrence sites evenly and thoroughly. Cotton is now in full bloom, and the plants are tall, so when spraying, be careful and thorough, focusing on spraying the undersides of the middle and lower leaves of cotton, strictly preventing missed spraying, and truly ensuring the quality of each spraying. Because aphids reproduce quickly, if one spraying is not thorough, it will leave many surviving insects and increase the difficulty of the next control. Generally, the amount of spray liquid used is 50-60 kg per mu.
3. It is recommended to choose some new pesticides. For plots where the control effect of conventionally used traditional pesticides such as acetamiprid and imidacloprid is not obvious, new pesticides such as 10% nitenpyram aqueous solution, 20% carbosulfan emulsifiable concentrate, or 10% clothianidin can be selected for control. Generally, 10% clothianidin wettable powder at 20 grams per mu or 10% nitenpyram aqueous solution at 20 ml per mu.
4. The timing of pesticide application should be appropriate. During high temperatures, avoid midday and apply pesticides as much as possible in the early morning and evening, preferably before 10 a.m. and after 4 p.m.; on the one hand, this can ensure personal safety, and on the other hand, it can avoid rapid evaporation and loss of the spray liquid caused by high temperatures, which reduces efficacy.
I. Occurrence situation
At present, cotton summer aphids are widespread in Hengshui City, with heavy damage in some plots. In Wuyi County, the number of aphids on three leaves per 100 plants is 3000-5000, with a maximum of more than 20,000, and severe leaf curling has occurred; in Gucheng, the highest plot had more than 10,000 aphids on three leaves per 100 plants, with a leaf-curling plant rate of 36%. The meteorological department predicts that in July our city will still maintain high-temperature weather, with precipitation close to normal years; hot, humid weather with alternating sunshine and rain favors the occurrence of cotton summer aphids. Here we remind the broad community of farmers to closely strengthen field observation, apply pesticides scientifically and promptly, and reduce the yield loss caused by cotton aphids to a minimum. The field chemical control methods for cotton aphids are provided below:
II. Control methods
1. Rotate the pesticides used. Rotate field conventional pesticides such as acetamiprid, imidacloprid, and chlorpyrifos to reduce the likelihood of aphids developing resistance; once aphids develop resistance to a certain chemical pesticide, even increasing the number of applications and increasing the pesticide concentration will not achieve the ideal control effect.
2. Spray the occurrence sites evenly and thoroughly. Cotton is now in full bloom, and the plants are tall, so when spraying, be careful and thorough, focusing on spraying the undersides of the middle and lower leaves of cotton, strictly preventing missed spraying, and truly ensuring the quality of each spraying. Because aphids reproduce quickly, if one spraying is not thorough, it will leave many surviving insects and increase the difficulty of the next control. Generally, the amount of spray liquid used is 50-60 kg per mu.
3. It is recommended to choose some new pesticides. For plots where the control effect of conventionally used traditional pesticides such as acetamiprid and imidacloprid is not obvious, new pesticides such as 10% nitenpyram aqueous solution, 20% carbosulfan emulsifiable concentrate, or 10% clothianidin can be selected for control. Generally, 10% clothianidin wettable powder at 20 grams per mu or 10% nitenpyram aqueous solution at 20 ml per mu.
4. The timing of pesticide application should be appropriate. During high temperatures, avoid midday and apply pesticides as much as possible in the early morning and evening, preferably before 10 a.m. and after 4 p.m.; on the one hand, this can ensure personal safety, and on the other hand, it can avoid rapid evaporation and loss of the spray liquid caused by high temperatures, which reduces efficacy.