Double-attraction method to control Frankliniella occidentalis (Pergande) in pepper crops in Tunisia

Abstract

Blue sticky traps with and without pheromone capsules were used to monitor and control Frankliniella occidentalis Pergande (1895) (Thysanoptera; Thripidae) in pepper crop greenhouses in Tunisia. Traps containing pheromone capsules could catch significantly more thrips than those without capsules, proving their efficiency in attracting and controlling this pest. In fact, greenhouses with traps with pheromone capsules caught 585.1, 526.7, and 668.8 adults/trap in a greenhouse with 10 traps with pheromone capsules on April 12, 19, and 26, 2012, respectively. The capture in a greenhouse with five traps with pheromone capsules was about 456.2, 412.8, and 431 adults/trap while in a greenhouse with five traps without pheromone capsules, the capture of F. occidentalis adults numbered 198, 257, and 302 adults/trap for the same three dates. Furthermore, traps with pheromone capsules captured males and females in equal numbers while traps without capsules caught much fewer males than females: 218.2 males/trap on April 26, 2012 in a greenhouse with five traps with pheromone capsules and 212.8 females/trap, 322.4 males/trap, and 342.3 females/trap in a greenhouse with 10 traps with pheromone capsules. In neither case were the differences significant. In contrast, in a greenhouse with five traps without pheromone capsules, the number of adults was about 88.6 males/trap, a significantly lower amount than the number of females/trap (213.4). This indicates that this pheromone plays a double role as a sex pheromone and as an aggregation pheromone by attracting both sexes. In fact, this double attraction approach improved the efficiency of these capsules by preventing the mating of untrapped females with males. This induced a high percentage of males and led to a decline in the thrips population on pepper flowers. Ten blue sticky traps with pheromone capsules reduced the thrips population more effectively in one week only than the use of five sticky traps, which took two weeks to achieve the control.