Abstract: To improve the integrated pest control efficacy of transgenic insect-resistant cotton and natural enemies, biological control efficacy and ecological effects of mass-releasing Trichogramma chilonis in transgenic insectresistant cotton (cv. Lumianyan15) field were surveyed in Huimin county, Shandong province in 2002, with the chemically controlled cotton field as control. Trichogramma showed high control efficacy on cotton bollworm eggs after three times of release both in the second and in the third generation bollworm periods. The parasitism on the second and third generation bollworm eggs were 66.0%-70.7% and 76.0%-81.2%, respectively, which were significantly higher than that in the control (second generation: 7.0%-12.3%, third generation: 5.2%-7.4%). And the injury rate of cotton buds and bolls in the second and third generation bollworm were 2.2% and 3.1%, respectively, which were significantly lower than that in the control (second generation: 8.5%, third generation: 20.9%). In the second generation bollworm period, number of bollworm eggs or larvae in the Trichogramma released cotton field did not differ to that in the chemically controlled field. But in the third generation, there were significantly less bollworm eggs and larvae in the Trichogramma released cotton field. There were more predators in the Trichogramma released cotton field. These results indicated that cotton bollworm in the transgenic insect-resistant cotton field can be effectively controlled by mass-releasing of T. chilonis. And the biocontrol method is also beneficial to predator protection in the cotton fields.

Key words: Transgenic insect-resistant cotton, Helicoverpa armigera, Trichogramma chilonis, Pest control efficacy

CLC Number: 

• Q986.1