Influences of chlorpyrifos on antioxidant enzyme activities of Nilaparvata lugens.

The brown planthoppers (Nilaparvata lugens, BPH) resistant to chlorpyrifos were selected in laboratory for eight generations. In the full course, the successive changes of activities of SOD, CAT and POD were analyzed. The analyses revealed that increasing of LD50 value was parallel to increasing of SOD, CAT, and POD, all of which increased gradually generation by generation.

Effect of fipronil on brain and muscle ultrastructure of Nilaparvata lugens (Stål) (Homoptera: Delphacidae).

The ultrastructure of Nilaparvata lugens brain cells was damaged by treatment at different fipronil concentrations. The cell showed swollen mitochondria and vacuolization, but no mitochondrial cristae. Rough endoplasmic reticulum (RER) fragmentation and degranulation were seen.

Cross-resistance of bisultap resistant strain of Nilaparvata lugens and its biochemical mechanism.

The resistant (R) strain of the planthopper Nilaparvata lugens (Stål) selected for bisultap resistance displayed 7.7-fold resistance to bisultap and also had cross-resistance to nereistoxin (monosultap, thiocyclam, and cartap), chlorpyrifos, dimethoate, and malathion but no cross-resistance to buprofezin, imidacloprid, and fipronil. To find out the biochemical mechanism of resistance to bisultap, biochemical assay was done.