Parasitization Rate of Helicoverpa armigera Hübner (Lepidoptera:Noctuidae) Eggs After Field Releases of Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) in Cotton in Cukurova Region of Turkey

摘要

The control of the noctuid Helicoverpa armigera Hiibner (Lepidoptera:Noctui-dae) with Trichogramma evanescens Westwood (Hymenoptera:Trichogrammatidae) on a cotton (Malvaceae) farm in Turkey is reviewed. Helicoverpa armigera has five generations in a year, but only three attack cotton in the East Mediterranean region of Turkey. Releases of T. evanescens are made twice against each of the first three generations of H. armigera in the years of 2004-2005. In each release, 120,000 parasitoids ha~(-1) were released, resulting in 62.9% and 71.6% parasitism and the numbers of larvae of H. armigera were reduced by 76.8％ and 80.6％, respectively. In fields where insecticides were applied, the numbers of larvae of H. armigera were reduced by 57.1％ and 77.1％, respectively. Furthermore, it was observed that population of natural enemies was increased in released parasitoid plots, with an average of 33 to 39 Chrysoperla carnea (Steph.) (Neuroptera:Chrysopidae) were encountered in 25 plants. Pollen-generating plants (maize, okra, weeds, etc.) probably increased the density of the predator. The cultivation of okra as a trap plant can be recommended especially in cotton fields where parasitoid release was conducted. The results of biological control of the noctuid H. armigera by T. evanescens appear promising.