Selectivity of alternative products to Telenomus podisi Ashmead (Hymenoptera: Scelionidae)

Abstract

The objective of this study was to evaluate the selectivity of alternative products to the egg parasitoid Telenomus podisi (Ashmead) (Hymenoptera: Scelionidae). The products used were Oil Geranium, Natualho®, Pironat®, Rotenat®, Natuneem® and Compostonat at the concentration recommended by manufacturer. Was sprayed 0.2 mL-1 of grout on cards containing 25 eggs of Euschistus heros (Fabricius) (Hemiptera: Pentatomidae) and sterile distilled water as a control. For the free-choice test, a female T. podisi was confined in a glass tube with two cards containing eggs of E. heros one being sprayed with treatment and other with sterile distilled water. . In the no-choice test, a female of T. podisi was confined ina a glass tube containing a card with eggs of E. heros, for a period of 24 h, the card being sprayed with the product prior or subsequent to parasitism. The parasitism percentage, emergence percentage, egg-adult period and sex ratio were evaluated. In free-choice test, the products Compostonat, Natualho® and Geranium Oil reduced significantly the percentage of parasitism. Similar reduction was also observed in no-choice test for Natualho® and Geranium oil in pre and post-parasitism. In pre-parasitism Compostonat and Geranium oil reduced the emergence and egg-adult period was affected by Natualho®. In post- parasitism there was a reduction in the number of eggs with signs of parasitism when the product sprayed was Rotenat®. The sex ratio of emerged adults was reduced by Natualho® and Geranium Oil. Natuneem® was the only product selective to T. podisi in all parameters evaluated.

Keywords

• Euschistus heros; Non-target organisms; Parasitoids