Bacillus thuringiensis Berliner and Anticarsia gemmatalis Hübner (Lepidoptera: Erebidae) under the action of plant extracts

This study aimed to evaluate the effect of aqueous plant extracts of jambolan, Syzygium cumini (L.) Skeels (Myrtaceae), castor bean, Ricinus communis (L.) (Euphorbiaceae), grape japan, Hovenia dulcis (Thumberg) (Rhamnaceae) and urucum, Bixa orellana (L.) (Bixaceae) at a concentration of 10% on Bacillus thuringiensis subsp kurstaki(Btk) and on Anticarsia gemmatalis (Lepidoptera: Erebidae), and the association of these on A. gemmatalis. The treatments consisted of aqueous extracts and Btk alone and the mixture of extract with Btk. These were incubated in a horizontal shaker (30 ± 2°C, 150 rpm for 2 h) and then applied to artificial diet cubes for A. gemmatalis in Petri dishes. As a control it was used sterile distilled water. Each treatment consisted of 4 Petri dishes (repetition) with 25 second instar larvae each. The disches were placed in a climatic chamber (27 ± 2°C, relative humidity 70 ± 10% and 14 h photoperiod), assessing the mortality after 24, 48 and 72 h. The percentage pupal and pupae weight of surviving insect were also assessed. None of the extracts showed insecticidal eff for A. gemmatalis and negative eff for crystals Btk. The cumulative mortality caused by extracts of grape japan, jambolan, urucum and castor bean were respectively 54.73; 46.09; 47.19 and 65.73%, diff significantly from the control (95.74%). The average weight of pupae did not diff significantly among treatments. The association of extracts of grape japan, urucun and castor bean with Btk caused 100% cumulative mortality in A. gemmatalis.