The second generation of the cotton bollworm has entered its peak outbreak period; be on alert for damage to a variety of crops.

Release Date:

2018-06-27

　　According to monitoring by the National Pest and Disease Forecasting Regional Stations, since mid-June, adult cotton bollworms of the first generation have entered their peak emergence period. Trap catches in the Huanghuai, North China, and Northwest regions have been relatively high, and meteorological conditions are favorable for the occurrence of the second generation of cotton bollworms in northern areas. It is expected that this year, the second generation of cotton bollworms will be widespread across most of northern China. Corn 、 Peanut 、 Soybean The pest is expected to occur at a moderate to severe level in vegetable and other crops, with a marked trend toward increased damage in the North China and Northwest regions. In cotton-growing areas, Bt cotton fields are likely to experience only mild infestations. The projected affected area in cotton fields is approximately 10 million mu, while that in other crop fields is about 30 million mu. The peak period of larval damage from the second generation will occur from late June to early July.
　　1 In North China, Northwest China, and most of the Huanghuai region, the population of the first-generation cotton bollworm is relatively high.
　　In various localities, in late May... Wheat According to field surveys of host crops, the average residual pest density per mu for the first generation of cotton bollworm was 86 in Hebei, 41 in Shandong, and 70 in Manas, Xinjiang. In Fucheng, Anxin, and Guantao in Hebei, as well as in Gaomi in Shandong, the numbers exceeded 100 per mu. Since early June, adult cotton bollworms have entered their peak emergence period, with moth populations remaining relatively high across the Huanghuai, North China, and Northwest regions. In Anyang, Henan; Shanghe, Shandong; and Wuyi, Hebei, light-trap catches have reached their highest levels since 2011 (see the table below for detailed data). In Ningxia, numerous localities have reported sightings, with sex‑pheromone trap catches of 244 and 857 moths in Huinong and Nongken, respectively; in Chaoyang, Liaoning, and Alashan and Bayannur in Inner Mongolia, trap catches have exceeded 100 moths.

　　Number of adult cotton bollworm moths trapped by light traps from June 1 to 19, 2018

　　2 Crop cultivation is conducive to the occurrence and damage caused by the cotton bollworm.
　　This year, in each cotton-growing region Cotton The planted area remains relatively stable, with Bt cotton accounting for a high proportion of the total in the Yellow River Basin, the Yangtze River Basin, and the Xinjiang cotton-growing region. Bt cotton exhibits consistent insect‑resistance efficacy, effectively controlling the second generation of the cotton bollworm; as a result, cotton fields often show a high egg count but low larval populations and only mild damage. Corn 、 Peanut 、 Soybean Vegetables and other crops are widely cultivated, providing favorable host conditions for the reproduction and damage caused by the cotton bollworm; consequently, its harm to non‑cotton crops will intensify. Moreover, the cotton bollworm has developed resistance to organophosphates, pyrethroids, and carbamates. Pesticide High levels of resistance develop, and older-stage larvae exhibit increased tolerance to the pesticide, leading to reduced control efficacy and more severe field damage.
　　3. High temperatures and drought in northern regions are conducive to the occurrence and damage caused by the cotton bollworm.
　　According to forecasts from the National Climate Center, from late June to early July, most of northern China is expected to experience above-normal precipitation and temperatures higher than average, with western and northern North China seeing anomalies 1–3°C above normal—conditions that are highly favorable for the occurrence and damage caused by the cotton bollworm.
　　In recent years, the cotton bollworm population has increased markedly, with the second generation migrating from cotton fields to other crops and causing damage. Due to its habit of boring into and damaging growing points, this pest will… Corn 、 Peanut 、 Soybean It causes severe damage to crops such as vegetables during their seedling stage. Local authorities should strengthen field surveys of all crops and promptly provide guidance on the scientific management of egg stages and early‑instar larvae, thereby reducing yield losses and ensuring the safe growth of crops.