Recherche d'alternatives aux pesticides chimiques pour lutter contre Tuta Absoluta (Meyrick, 1971) et de stratégies d'optimisation de l'utilisation de Nesidiocoris Tenuis (Reuter, 1895), prédateur de ce ravageurau Burkina Faso

Abstract

Solanum lycopersicum L., a tomato species is the second most widely grown and consumed vegetable in Burkina Faso. However, it is attacked by many pests, of which Tuta absoluta Meyrick, a leaf miner, has been found to cause yields reduction. The general objective of this study was to search for alternatives to chemical control of T. absoluta. The study focused on the predatory bug Nesidiocoris tenuis. Indeed, it was revealed from our literature review that this bug was an effective control agent which has been commercialized in many countries. In combination with mass trapping and the use of Bacillus thuringiensis, this bug could be a credible alternative with regards to Burkina context. The ability of N. tenuis to feed on T. absoluta eggs is increasing during its development stage. L1 larvae (18.4± 12.7 eggs in 24 h) are the less voracious compared to the adults (45.0 ± 9.9 eggs in 24 h). Nesidicoris tenuis was unable to predate L1 larvae of T. absoluta at L3 stage (3.0 ± 1.5 larvae in 24 h). This ability also increases with its development stage until the adult stage from which it consumed 11.0 ± 1.8 larvae in 24 h. Only the L5 larvae of N. tenuis can predate T. absoluta at L2 stage (4.4 ± 1.6 larvae in 24 h). The exposure of N. tenuis larvae at L5 stage to insecticides shows that Abamectin, Emamectin benzoate, Spinosad and Spinetoram with LC50 between 0.77 and 4.94 mg/l, when used recommended dose are toxic with a 100% probability of killing the entire population of the predators in 24 h. On the other hand, the use of B. thuringiensis, neem oil, Jatropha curcas oil, extracts of Cleome viscosa, Ocimum basilicum and Parkia biglobosa will maintain part of the N. tenuis population in tomato plots. Overall, these results suggest that the use of N. tenuis could be considered as a promising integrated pest management strategy as bio-pesticides to fight against the spread of T. absoluta in Burkina Faso.