STUDY OF THE EFFECTIVENESS OF TWO METHODS: MASS TRAPPING AND LEAF AND FRUITS REMOVAL FOR THE CONTROL OF THE TOMATO LEAFMINER, Tuta absoluta MEYRICK (LEPIDOPTERA, GELECHIIDAE) IN TUNISIA

This work aims to develop alternatives to chemical sprays for the control of the tomato leafminer, Tuta absoluta (Lepidoptera, Gelechiidae). Thus, were evaluated in 2014 in two greenhouses planted with tomatoes during the period of intense insect activity through March to May, two techniques: Male mass trapping and cultural control. In plots conducted under mass trapping a high density of pheromone Jackson trap (120 per ha) was used and in plots conducted under cultural control, manual removal of T. absoluta damaged tomato leaf and fruits was carried out regularly usually at weekly interval.

Results indicated that on the whole, both techniques showed low effectiveness in the reduction of insect infestation compared with control. The densities of T. absoluta biological stages (eggs, young larvae and old larvae) and empty galleries per tomato leaflet did not vary between plots dedicated to mass trapping and cultural control compared with control at 5 sampling dates respectively 7, 17, 21, 28 and 35 days following the setup of the experiment. However, a significant difference was found between treatments regarding the density of eggs with a minimum in mass trapping plots (averaging 0.24±0.76 eggs per leaflet) compared with cultural control (1.19±2.33) and check plots (4.2±0.47), at day 42 suggesting an improvement in the effectiveness of mass trapping technique late in the season. The percentage of fruit infestation following three harvesting dates (on 24 March, on 16 April and on 25 April 2014) revealed an average percentage of infestation of 45% for all plots without significant difference among tested approaches except for the first harvesting date. Even though, not clearly evidenced, mass trapping technique could be a future method of T. absoluta control but further studies are needed to take advantage of this technique.