The Integration Between Trichogramma Evanescens West. (Hymenoptera: Trichogrammatidae) and Selected Bioinsecticides for Controlling the Potato Tuber Moth Phthorimaea Operculella (Zell.) (Lepidoptera: Gelechiidae) of Stored Potatoes

Abstract

The Integration BetweenTrichogramma EvanescensWest. (Hymenoptera: Trichogrammatidae) and Selected Bioinsecticides for Controlling the Potato Tuber MothPhthorimaea Operculella(Zell.) (Lepidoptera: Gelechiidae) of Stored PotatoesThe efficacy of the egg-egg parasitoidTrichogramma 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 ofT. evanescensand 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 ofP. operculellapupae, 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 ofP. operculellarecovered pupae. Virotecto and Agerin reduced rate of infestation and number of recoveredP. operculellapupae 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 ofP. operculellatunnels and percentages of edible parts after two months in storage. Data further indicated that the integration between the tested bioinsecticides andT. evanescensenhanced the control ofP. 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 (withoutTrichogramma) and combined treatments.

Potential for the Postharvest Biological Control of Phthorimaea operculella (Lepidoptera, Gelechiidae) by Blattisocius tarsalis (Mesostigmata, Blattisociidae)

“…However, the chemical control of PTM in tuber storage has limited potential since most insecticides cannot be safely applied to potatoes shortly before they are marketed for human consumption [15]. Under these conditions, both microbiological agents (granulovirus, Bacillus thuringiensis and nematodes) and macrobiological agents (Chelonus blackburni (Cameron), Copidosoma koehleri (Blanchard), Trichogramma chilonis Ishii and T. evanescens Westwood) have been applied with different levels of success [8,9,[15][16][17]. More recently, research has begun on the potential of using two species of predatory egg mites from the Blattisociidae family, Blattisocius mali (Oudemans) and B. tarsalis (Berlese), to control PTM [18,19].…”

Toxicity risk of insecticides to the insect egg parasitoid Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae)

“…The parasitoid occurs naturally in various crops under field conditions, where insecticides are frequently used in many countries . In this context, the impacts of insecticides on T. evanescens may be of economical and ecological importance because they may modify the population dynamics of several interacting species, including pest populations …”

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“…The greatest amount of tuber damage occurs immediately before harvest if the crop is left in the field prior to harvesting. Additional damage may occur in storage if conditions are not controlled properly [5][6][7].…”