کنترل آفت Helicoverpa armigera توسط زنبورهای پارازیتویید Trichogramma evanescence و Habrobracon hebetor در قالب برنامه رهاسازی اشباعی

Helicoverpa armigera is one of the most destructive pests in agricultural crops, causing significant damage to farms annually. The side effects of insecticides application and developing resistance to chemical pesticides in H. armigera have increased demands to implement non chemical approaches against this pest. H. armigera has been attacked by several biocontrol agents including Habrobracon hebetor and Trichogramma evanescence. Herein, we studied the performance of these biological control agents for controlling H. armigera in an augmentation program in field condition and compared the obtained results with insecticides application. The study was performed with five treatments and four replication in a split plot in time scheme arranged in Randomized Complete Block (RCB) design. The treatments were including H. hebetor, T. evanescence, H. hebetor + T. evanescence releasing, and two control treatments (limited chemical application –Con1 and conventional chemical control- Cont2). Analyzing data showed significant differences among treatments (F=10.5; df=4, 12; p<0.01) and among various harvesting dates (F=3.49; df=3, 36; p<0.05). TRICO-HABROBRACON and Cont2 with the lowest (6.69±0.62) and highest (9.19±0.93) number of the infested fruit were the most and least influential treatments. Mean comparison of the harvesting dates showed that the highest (8.4±1.14) and least (7.2±0.66) number of infested fruits were observed in the second and fourth harvesting sessions, respectively. Interaction between harvesting date and treatments also showed significant differences (F=15.2; df=12, 36; p<0.01). Tomato yield was another factor analyzed in the different treatments and results revealed significant difference among treatments in both main harvesting sessions (F=14.9; df=4, 12; p<0.01 and F=3.40; df=4, 12; p<0.05 for the first and second harvesting date, respectively). However, the treatments showed no significant difference in total harvested yield. By these results we can conclude that biological control agents can be used as a promising alternative with synthetic insecticides for sustainable control of H. armigera in tomato fields.