Publications scientifiques
Leïla Bagny Beilhe
David R. Hall
Gerben Martijn Ten Hoopen
Régis Babin
Agritrop (Cirad)
In Cameroon, pheromone traps appear interesting to monitor or even control Sahlbergella singularis populations on cocoa farms. The efficiency of traps baited with pheromones relies on a good knowledge of both visual and olfactory stimuli that attract cocoa mirids and on appropriate trap deployment in cocoa plantations. The aim of this preliminary study is first to compare the attractiveness of traps of different colors and baited with different pheromone blends. To achieve this purpose, we monitored a total of 90 traps of 3 different colors (30 red, 30 yellow and 30 white) and baited with 2 different pheromone blends, deployed in ten 1-ha plots (100 x 100m) PVC tubular traps were monitored from March on a weekly basis. Simultaneously, experiments in flight tunnel were conducted in the laboratory to confirm trends observed in the field. Secondly, to better understand how trap deployment influences mirid capture rate, we tested 3 trap densities in a total of twenty one 1-ha plots (100 x 100m) which received different treatments: 7 plots with a high trap density (16 traps ha-1), 7 plots with a medium trap density (9 traps ha-1) and 7 plots with a low trap density (4 traps ha-1). Traps were monitored on a weekly basis. Also, mirid populations and damage were assessed in each plot twice a year. Seven plantations with no trap were sprayed with insecticide according to spraying recommendations and were also monitored to evaluate the productivity gain or loss between the two control methods. Understanding the factors involved in oriented movements of mirids in the field, will help to formulate relevant recommendations to improve integrated management of S. singularis and potentially to reduce the economical cost of control strategies.
