Influence of Bacillus thuringiensis Berliner on the phytophagous activity of Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae) on kale leaves

The objective of this study was to evaluate the interaction between Bacillus thuringiensis (Bt) and Podisus nigrispinus in the phytophagous activity of the predator on kale leaves. The 6 treatments were as follows: T1, leaf immersed in distilled water and fed to Plutella xylostella larvae; T2, leaf immersed in suspension of Bt (Agree®) and fed to P. xylostella larvae; T3, leaf immersed in suspension of Bt (HD-1) and fed to P. xylostella larvae; T4, leaf immersed in water; T5, leaf immersed in suspension of Bt (Agree®); T6, leaf immersed in suspension of Bt (HD-1). The HD-1 strain was used at a concentration 3 × 108 spores/mL, and the commercial product Agree® was used at the concentration indicated by the manufacturer (0.5 g/333 mL). Kale leaf was replaced every 2 days and immersed in 1% acid fuchsin for 12 h to count the number of sheaths. The nymphs fed on only kale leaves immersed in water, HD-1, or the commercial product Agree® did not complete the nymphal period. When the nymphs were offered only leaves, the number of sheaths were 69.7, 45.2, and 19.33 for the control, HD-1, and Agree®, respectively, and when they were offered prey and leaves, the number of sheaths were 365.3, 217.2, and 133.8 for the control, HD-1, and Agree®, respectively. Consumption during nymphal development was higher for the product Agree® and HD-1 isolate (19.4 and 17.9) than for the control (14.6). The presence of Bt increases prey consumption and decreases the phytophagous activity of the predator.