Abdoolnabi Bagheri - Plant Protection Research Department, Hormozgan Agricultural and Natural Resources Research and Education Center, Agricultural Research Education and Extension Organization (AREEO), Bandar Abbas, Iran.
Majeed Askari Seyahooei - Plant Protection Research Department, Hormozgan Agricultural and Natural Resources Research and Education Center, Agricultural Research Education and Extension Organization (AREEO), Bandar Abbas, Iran.
Yaghoub Fathipour - Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran.
Maryam Famil - Plant Protection Department of Agricultural Organization of Hormozgan province, Iran.
Fatemeh Koohpayma - Plant Protection Research Department, Hormozgan Agricultural and Natural Resources Research and Education Center, Agricultural Research Education and Extension Organization (AREEO), Bandar Abbas, Iran.
Akhtar Mohammadi-Rad - Plant Protection Department of Agricultural Organization of Hormozgan province, Iran.
Shabnam Parichehreh - Department of Honeybee, Animal Science Research Institute of Iran, Agricultural Research Education and Extension Organization, Karaj, Iran.

Health and environmental side effects of chemical insecticides and development of resistant population of Helicoverpa armigera Hubner (Lepidoptera: Noctuidae) to pesticides have resulted in increasing demands for non-chemical control approaches against this pest. In this research, the efficacy of two biological control agents were studied under field condition. Treatments consisted of releasing Habrobracon hebetor (Say) (Hymenoptera: Braconidae), Trichogramma evanescence Westwood (Hymenoptera: Trichogrammatidae) and combination of H. hebetor + T. evanescence (HABROBRACON-TRICO). The results revealed significant differences in the number of infested tomato fruits among treatments and harvesting times. The infested fruits was the lowest (۲.۶۸ ± ۰.۱۴%) in plots treated by HABROBRACON-TRICO. Moreover, the highest (۳.۳۶ ± ۰.۵۰%) and the lowest (۲.۸۸ ± ۰.۲۲%) damaged fruits was recorded in the second and fourth harvesting times, respectively. There was significant interaction between harvesting times and treatments. Regarding the tomato yield in treatments, findings revealed significant difference among treatments in both main harvesting times. However, there was no significant differences in total yield in treatments. It could be concluded that biological control agents can be used as a promising alternative for synthetic insecticides in control of H. armigera in tomato farms without significant crop losses.

Biological control, Cotton bollworm, Tomato field, Chemical application