At present, cotton has entered the budding period, and some cotton fields have begun to see flowers, which is the key period of field management. On June 28, bozhou agricultural technology extension center organized plant protection monitoring and reporting technicians and cotton experts to conduct a census of the occurrence of diseases and insects in cotton fields in 7 cotton-planting townships (farms) in Bole City and Jinghe County: a total of 60 cotton fields were surveyed, sampling 140 points of about 100,000 mu, representing an area of about 450,000 mu. At present, cotton aphids are in the period of migration, proliferation, propagation and spread of harm, the occurrence of cotton aphids in Bole City has increased by 2 to 3 times compared with last week, and some cotton fields have appeared to have the phenomenon of rolling leaves and oil leaves, the benefit-harm ratio is less than 1:500, and the natural control ability is weak. In order to ensure high and stable cotton yields, the monitoring and control of cotton pests and diseases should be strengthened.
First, the field insect situation census live
On June 8, 2018, the field cotton aphid first saw the central plant, which was 8 days later than the previous year, which was basically the same period as the calendar year. On June 14, the cotton field in Bole City was investigated as a point (lighter than the same period last year). The average aphid field rate was 48.1%, the cotton aphid spot rate was 47.2%, the average aphid rate was 1-7.1%, the amount of aphids per plant was 2 to 11, and the maximum aphid amount per plant was 58.
On June 26, in the suburbs of Bole City, Siding Yicha cotton field system survey, hundreds of plants with aphid rate of an average of 6%, the highest number of aphids per plant is 390, 3 curly leaf plants, curly leaf area of 0.3 to 4 square, winged aphids: wingless aphids = 1:80, and some 15% of the aphids on the curly leaf plants are winged and aphids. The spread of cotton aphids in cotton fields has reached its peak. The amount of natural enemies in the cotton field is small, and the benefit-harm ratio is less than 1:400.
Due to the frequent recent gust weather, it is more favorable to the migration and propagation of cotton aphids, bole city has a cotton aphid field rate of 100%, Jinghe county has a cotton aphid field rate of 25%, Jinghe county is lighter than Bole city, Bole city cotton field has an aphid plant rate of more than 8%, oil leaf field rate of 11.6%, the average inverted three-leaf aphid volume per plant is 70 to 4900 heads, the average curl plant rate is 4.7%, the curl plant aphid volume is about 9800 heads, of which winged and aphids account for 16% of the total aphid volume. According to the monitoring of the state plant protection station, the current population of cotton long pipe aphid in the cotton field is still showing an upward trend, and some small dots have a leaf flow phenomenon, and cotton aphids and long pipe aphids are mixed. At present, cotton aphids in Bole City are rapidly spreading in the fields and breeding hazards. According to the forecast of the state meteorological bureau, the average temperature of the whole state in the near future is between 23 and 27 °C, and the relative humidity in the field is 40 to 60%, which is conducive to the increase of the cotton aphid base. At the same time, the survey had an average of 0.62 natural enemy units per 100 plants, which was slightly less than the same period last year, mainly ladybirds and grass bell adults, and the ability of natural enemies to control insect pests was weak.
2. Meteorological conditions
According to the forecast of the state meteorological department, the average temperature in late June is high, of which the Bole area is about 25 °C and Jinghe County is 27 °C; in late June (after the 29th to July 1), there is a small amount of rainfall throughout the state, and the local area can reach small to moderate amounts, accompanied by 4 to 5 northwest gusts.
Third, the occurrence of trend analysis
At present, cotton aphids have formed dots in cotton fields to occur widely. Affected by the weather process of sunny and rainy weather, it is expected that the aphid will show a local biased occurrence trend, and the harm of local cotton field cotton aphids in the suburbs and near settlements will be more serious.
4. Prevention and control recommendations
1. At present, the "Fu Aphid" has begun to enter the general development period in the cotton field, and the county (city) township (town) government should strengthen the prevention and control command of the field, organize and coordinate the cotton farmers in various villages to carry out joint prevention and control in a timely manner, and ensure the quality of spraying to reduce the harm of cotton aphids in the middle and late stages.
2. In view of the characteristics of cotton aphids that are prone to resistance, it is recommended to use 70% acetamidine emulsion or 10% imidacloprid wettable powder 20 grams plus 20% amidoxic emulsion 20 grams of water 30-45 kg / mu or 5% Aktai 20 grams per mu to water 30-45 kg / mu (remember that the concentration is not too large, in order to prevent drug damage), for drug control.
Author: Sai Liman, Source: Bozhou Agricultural Technology Extension Center, Graphic Editor: Tianshan Plant Protection, please indicate the source when reprinting!