| Abstract: | Fipronil, a compound belonging to a new chemical family, the phenylpyrazols, was tested as a barrier treatment in Mauritania against bands of hoppers of the desert locust (Schistocerca gregaria, Forskal1775). An ultra-low volume formulation (ADONIS 12.5UL) was applied at 15.7 and 16.6/km. The doses were 1.96 and 1.04 g ai/ protected ha. Two sites of approximately 2800 and 7200 ha were sprayed from a helicopter flying at 20m. There were 12 track spacings, ranging from 330m to 2600m. The effects of fipronil on hopper bands were determined by comparison with the initial locust populations at the two sites. Several hopper bands were monitored in two untreated areas. The hopper bands were controlled within two days in the area up to 500m from the flight path, within 7 days in the area between 1000 and 2000m, and within 12 days in the area between 2000 and 2600m. The speed of mortality was related to the upwind distance from the flight path. When ADONIS 12.5UL (12.5g ai/l of fipronil) is applied at 16 l/km, at 20m height, with track spacings up to 1000m, the efficacy was similar to that obtained with a blanket treatment (11 g ai/ha) performed the previous year in Mauritania. |
