The insecticidal activity of a cockroach gel bait containing a chitin synthesis inhibitor, noviflumuron, was evaluated using laboratory and field strains of the German cockroach, Blattella germanica (L.). Noviflumuron gel bait (0.01-5 mg g-1) caused ≥90% nymphal mortality to laboratory and field strains of B. germanica in choice tests after 11 and 19 days of continuous exposure respectively. In 1 m x 1 m bioassay arenas, laboratory strain B. germanica population levels exposed to 5 mg g-1 noviflumuron bait or 0.1 mg g-1 fipronil gel bait were significantly lower than untreated population levels after 3 weeks and 1 week of exposure respectively. Various noviflumuron bait exposure periods (2, 4 and 7 weeks) caused similar population reductions, with a mean of 99.3 (±0.3)% at 7 weeks. Fipronil gel bait caused 100% population reduction at 2 weeks post-exposure. The control population increased 89.0% at 7 weeks. In a simulated kitchen experiment with mixed stage laboratory populations, cockroach trap catches decreased 96.8 (±2.0)% at 8 weeks in the 0.5 mg g-1 noviflumuron bait treatment. The trap catches in the control increased 506.5 (±493.7)% during the same period. Trap catch reduction by 0.1 mg g-1 fipronil gel bait reached 100% at 4 weeks. Noviflumuron bait caused significantly lower nymph/total ratios to B. germanica populations in bioassay arenas from 2 weeks after exposure, demonstrating its effectiveness as a control agent for B. germanica with a pattern of activity similar to that expected from a chitin synthesis inhibitor.
All Science Journal Classification (ASJC) codes
- Agronomy and Crop Science
- Insect Science
- Blattella germanica
- Gel bait