Forecast Of Cotton Main Diseases And Pests In Jingzhou In August

The first and the fourth generation

1. Occurrence period: according to the investigation of the West Gate Branch of Taihu farm in July 30th, and the age analysis of the third generation of Helicoverpa armigera larvae, the 3-6 instar larvae accounted for 57.14%, 14.29%, 14.29 and 14.29% respectively. According to the analysis of the age of the three generation of cotton bollworm in Songzi in July 26th and 27th, the age of 2-6 instar larvae in Songzi accounted for 11.11%, 22.22%, 22.22%, 22.22% and 11.11% respectively. The proportion of the larvae in the age group of the larvae was respectively 0, 2, 3, 2, 14.29 and 14.29% respectively.

According to the dating date, it is estimated that the fourth generation of bollworm eggs will begin to bloom in August 9th or so, and the peak period of spawning in the field will be before August 16th.

2.

3, the main basis: (1) the third generation of cotton bollworm is low in quantity. According to our station system observation, the average number of insect pests per day is 1.3, which is 76.9% lower than that of 2000-2009 years. According to the investigation of plant protection station in public security, Jianli, Songzi and other counties, the average number of insect pests is 0.1-4.5 in the peak period of the larva, and the weight of the public security is as high as 15, which is higher than that of the same period last year.

(2) most cotton fields grow green in August, buds full of branches and rich food, which will benefit the fourth generation of cotton bollworm.

(3) the weather forecast for August is relatively small and the temperature is high. It will be beneficial to the fourth generation of Helicoverpa armigera.

Two.

1. Occurrence and amount of occurrence: the Bemisia tabaci in cotton fields will be moderately biased (grade 4), and the amount of local plots in the mixed vegetable and cotton planting area will reach the maximum level (Grade 5). The peak period will be in the middle and late 8 months.

2, the main basis: (1) according to my station system observation, this year cotton field Bemisia tabaci appeared on 11 days in June, 6 days later than last year. In July 30th, the average number of nymphs per plant in the cotton field was 122, which was 45.3% lower than that in the same period last year.

(2) in August, most cotton fields grew green and had sufficient food sources, which was beneficial to the propagation of Bemisia tabaci.

(3) the weather forecast is low in 8-9 and the temperature is high, which will benefit the whitefly.

The three and fourth generation of bug bug

1. Occurrence period and occurrence amount: the fourth generation of the generation of blind bug is moderately occurring (grade 3), but the cotton fields with large intercropping area, close to vegetable area, high base and late growing green can reach moderate weight occurrence (grade 4). The occurrence period of young nymphs will be around mid August.

2, the main basis: (1) according to the observation of the plant protection station system, the average generation of the third generation of bugs is 7.3, which is 2 higher than that of the 2000-2009 year 10 years.

(2) according to the survey conducted by Jianli, Jingzhou, Songzi and public security, the average generation of 0.5-14 on the peak of the third generation of bugs is 60, which is significantly higher than that of the same period last year.

(3) the weather forecast is low in August and the temperature is high. It will inhibit the occurrence and damage of the four generation of the bug.

Four, prevention and control advice

August is the critical period for the occurrence and control of the fourth generation of Helicoverpa armigera and cotton Bemisia tabaci, and the control of pests and diseases should be the main pests. Cotton pest control, second generation of pink bollworm, red spider, Spodoptera litura, and boll stage diseases should be carried out.

All localities should strengthen field investigation, closely monitor the occurrence of various pests and diseases in cotton, and seriously organize the campaign of prevention and control.

1, continue to open the light to induce moths, trapping cotton bollworm adults, reduce the amount of eggs laid in the field.

2, conscientiously grasp the fourth generation of Helicoverpa armigera spawning period to the low larval stage of chemical control work.

Any field with 30 eggs per day or 5 larvae of a hundred larva larvae should be treated immediately. The agents are mainly single agents, and they can be selected as: methylene salt, chlorpyrifos, acephate, beta cypermethrin and so on. When the field insects are large, they can be properly selected.

3. For cotton fields with large amounts of Bemisia tabaci, dimethyl ether urea, biphenyl pyridine, acetamiprid and imidacloprid can be used alone or with avermectin mixed spraying to prevent and control. The spray is mainly sprayed on the opposite side of the leaf, once every 7-10 days, 2-3 times a day, and attention should be paid to altering the drug and specialized control.

4. For the fourth generation of the blind bug, with 25 insect heads, the pesticides such as chlorpyrifos, malathion and organophosphorus pesticides can be sprayed.

5. Combined with the control of fourth generation of cotton bollworm, bug bug and Bemisia tabaci, spraying 0.3% potassium dihydrogen phosphate solution to prevent the occurrence of late blight. Meanwhile, the early stage cotton fields can be added with fungicides such as chlorothalonil, dactone and more than 3 to prevent boll disease and reduce the occurrence of rotten bolls.