Produtos alternativos e associação com Trichogramma pretiosum Riley (Hym.: Trichogrammatidae) visando o controle de Helicoverpa zea (Boddie) (Lep.: Noctuidae) em tomateiro

Abstract

The tomato fruitworm (TFW), Helicoverpa zea (Boddie) (Lep.: Noctuidae) is considered an important pest in several crops. The purpose of the study was to evaluate the use of castor bean oil, garlic and tobacco extracts to control H. zea larvae, and the influence of these products on the egg parasitoid Trichogramma pretiosum Riley (Hym: Trichogrammatidae). Larval mortality of TFW was investigated when treated with the alternative products at different concentrations through ingestion and contact aplication. Tests of selectivity and susceptibility of T. pretiosum were performed by spraying TFW eggs prior and post parasitism. Castor bean oil at 3% (v/v) through ingestion and contact treatments of TFW larvae caused mortality of 44 and 20%, respectively. Garlic extract at all concentrations and type of application resulted in TFW mortality equal or greater than the tobacco extract. The number of eggs parasitized by T. pretiosum was reduced by castor bean oil, while other biological parameters were not affected. Garlic extract positively interacted with T. pretiosum resulting in greater number of eggs parasitized, although it was observed a lower number of individuals emerging per parasitized egg in selectivity test. Castor bean oil was toxic to TFW larvae in both types of application. Garlic extract produced better results when ingested by TFW larvae and it was superior when compared to tobacco extract to control TFW larvae. Based on the results, castor bean oil and garlic extract are compatible with T. pretiosum, but the former one should be applied after the parasitoid release. Therefore, castor bean oil and garlic extract are promising as phytosanitary tools to control H. zea larvae.