Activity of plant aqueous extracts on Bacillus thuringiensis and their interactions on Anticarsia gemmatalis (Lepidoptera: Erebinae)

Abstract

The association of plant extracts and B. thuringiensis may be important in situations that control of different insects species is required and/or control of insects in various development stages. However, extracts may have different effects on B. thuringiensis, compromising their mode of action. Thus, the objective of this study was to evaluate the activity of aqueous plant extracts on Bacillus thuringiensis subsp. kurstaki (Btk) and their interactions on Anticarsia gemmatalis (Lepidoptera: Erebinae). Cherry plant extracts (Eugenia uniflora), pepper (Capsicum baccatum), trumpet (Brugmansia suaveolens) and grape japan (Hovenia dulcis), were used at 5% concentrations. For compatibility studies, the extracts were mixed with Thuricide® (Btk) and the parameters evaluated were Colony Formation Units (CFU mL-1) for spores and, the A. gemmatalis mortality for crystals. The cherry extracts, pepper, and japan grape completely inhibited the CFU ml-1 of Btk and the cherry extract alone negatively affected the toxicity of Btk crystals, with significantly lower mortality of A. gemmatalis (20.40%) than that observed in the control with only Btk (79.44%). In the association between cherry, pepper, and grape japan extracts with B. thuringiensis, the extracts exhibited a negative effect in the formation of CFU. The cherry extract demonstrated a negative effect on crystals action.

Keywords

• Bactéria entomopatogênica
• Controle associado
• Extratos botânicos.