关键词: 红火蚁, 氟虫腈, 饵剂, 施用技术

Abstract:

Objective　The efficacy of fipronil baits against Solenopsis invicta was determined and the technical specifications for application of the baits were developed. Methods　A combination of small?scale field experiments and single nest experiments was used. Results　The  results  of  small?scale  field  experiments  using  the  three  concentration  gradients, 0.0005%, 0.005% and 0.05%, showed that the 0.05% fipronil baits had the best killing effect, which was evident beyond 3 d after application on a dose of 6 g for each ant nest in the experiment areas. The adjusted decrease rate of active ant nests was 9.52%, and that of worker ants was 43.94%. Significant control effects were observed beyond 6 d after application of the baits, the adjusted decrease rate of active ant nests being 74.03% and that of worker ants 98.05%. At day 27 and 30, both decrease rates reached 100%. Additionally, the baits had no obvious effect on any other arthropod. The results of single nest experiments showed that the optimal dosage of the 0.05% fipronil baits for 25-30 cm mature nests was 5 g/nest. It was shown that the active time of feeding for S. invicta was beyond 17:00 in summer and from 9:00 to 17:00 in winter. Evenly spraying the baits on the surface of ant hills would contribute to the shortest time for worker ants to deposit the baits. Conclusion　The 0.05% fipronil baits can rapidly and completely kill S. invicta  ants  while  sparing  non?target  arthropods. The  technical  specifications  for  application are as follows: based on the recognized optimal dosage, 5 g/nest, for 25-30 cm mature nests, the actual application amount can be adjusted according to the size of nest. The optimal application time was after 17:00 in summer and from 9:00 to 17:00 in winter. The best way to apply the baits is by evenly spraying them on the surface of ant hills.

Key words: Solenopsis invicta, Fipronil, Bait, Application method