The integration between Trichogramma evanescens west. (Hymenoptera: Trichogrammatide) and selected bioinsecticides for controlling the potato tuber moth Phthorimaea operculella (Zell.) (Lepidoptera: Gelechiidae) of stored potatoes

The efficacy of the egg-egg parasitoid Trichogramma evanescens (Hymenoptera: Trichogrammatidae) and certain bioinsecticides (e.g., Neemix, Virotecto, Agerin, Dipel 2x and Spinosad) for controlling the potato tuber moth (PTM), Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) under storage conditions was studied. Single and combined treatments of T. evanescens and the bioinsecticides were tested. Neemix and spinosad were evaluated as spray treatments. Virotecto, Agerin and Dipel 2x were evaluated as dust and spray treatments. Data were recorded in terms of rate of infestation, reduction of infestation, number of P. operculella pupae, and number of mines per 20 tubers as well as percentage of edible parts. Data revealed that the percentage of infestation in the control treatment was as high as in the Neemix treatment being 96.67 and 90% after one and two months of storage, respectively. Obviously, Spinosad and Dipel 2x were the most effective bioinsecticides in reducing tuber infestation and number of P. operculella recovered pupae. Virotecto and Agerin reduced rate of infestation and number of recovered P. operculella pupae over that of the control, but their effect was significantly lower than that of Spinosad or Dipel 2x. Moreover, there were significant differences among treatments in the form of the number of P. operculella tunnels and percentages of edible parts after two months in storage. Data further indicated that the integration between the tested bioinsecticides and T. evanescens enhanced the control of P. operculella. Significant differences in percentages of infestation, edible parts, number of recovered pupae as well as number of mines in stored potatoes existed between individual treatments (without Trichogramma) and combined treatments.