Abstract:

To understand the control effects of 5 biological insecticides against the younger nymphs of Nilaparvata lugens, the field trials were made in rice through field spray. The results showed that, 7 days after single spray respectively at a dosage of 3000 mL/hm2 and 1800 g/hm2, the control effects of veratridine 0.5% WP and Beauveria bassiana 4.0×1010 spores/g WP were better, i.e. 78.6% and 79.0% respectively, and the efficacy of the two biological insecticides was similar to that of buprofezin 25% WP at a dosage of 600 g/hm2, but these biological insecticides took effect more slower than chemical insecticides. When the two pesticides were mixed at a half dosage of the recommended dosage for spraying alone, the control efficacy of B. bassiana＋buprofezin was the best, i.e. 65.0% in 1 day and 87.6% in 7 days after treatment. Therefor B. bassiana and veratridine can substitute partly for chemical insecticides to control younger nymahs of N. lugens.