Locust control by means of selective baiting

Summary Renewed research into baiting as an alternative method of locust control was recently initiated by the Plant Protection Research Institute, Pretoria, South Africa. This technique was reexamined in the light of increasing environmental concern over the repeated use of broad spectrum ultra low volume (ULV) pesticide sprays for the control of the brown locust, Locusiana pardalina, in the Karoo. Screened first in the laboratory to establish optimal dose rates, preliminary field trials in the Karoo with silafluofen 80 EC (Neophan), applied at a concentration of 2000 ppm in a bran bait formulation, demonstrated that rapid and effective control of nymphal bands could be consistently achieved. Rates of 2–10 kg of moistened bait/band, simply broadcast by gloved hand around roosting bands (n = 13) in the early morning, averaged 91% (range 67–100%) control. Median lethal time was 4.6 h in summer. Broadcasting the bait in a ±1-m-wide barrier around the roost before the insects completed their morning descent to the ground was the most effective method of dose transfer. Baiting at other times of the day was less successful. It was equally effective in summer and autumn and was successfully applied in both Karoo scrub and mixed grass biotopes favoured by the brown locust. Being a simple method of locust control, this technique could also provide employment for economically disadvantaged rural communities in the Karoo.