Chlorantraniliprole/lambda-cyhalothrin, a new insecticide mixture to control Tuta absoluta and Spodoptera littoralis in tomato.

A study was performed in the period May-July 2011 by Bioagritest test facility according to EPPO guidelines and Principles of Good Experimental Practice (GEP), in the land of Eboli (SA), southern Italy, with the purpose to test a new insecticide mixture in the defense strategies of processing tomato against Tuta absoluta and Spodoptera littoralis. The insecticide mixture Chlorantraniliprole 100 g/lambda-Cyhalothrin 50 g/l 0,4 It/ha was applied in a tomato field in four (A-B-C-D) application timings (a.t.) alone (treatment 2) and in two a.t. (A-B) combined with emamectin benzoate 0.5%, 1,5 Kg/ha (a.t. C-D) (treatment 3). Its effect in containing insect populations was compared with that exerted by emamectin benzoate 0.5%, 1,5 Kg/ha (a.t. A-B-C-D) (treatment 4) and the combination of chlorantraniliprole 35%, 0.115 Kg/ha (a.t. A-B) and indoxacarb 30% 0.125 Kg/ha (a.t. C-D) (treatment 5). Application of treatments (trt.) and mode of assessment (2 assessments), recording and measurements followed the guidelines foreseen by EPPO Standards PP1/150 and PP1/275. The lepidoptera infestation in the tomato crop was very high on both the leaves and fruits, and this enabled us to evaluate the efficacy of the tested products in conditions of severe pests infestation. If we consider the leaf damage, either as number of mines by T. absoluta or as % of leaf erosion by S. litteralis, all the treatments values were statistically lower than control, but with no difference among them. But when using as an infestation threshold the percentage of damaged fruits (much more relevant in economic terms), we observed statistically significant differences among treatments. Actually, treatment with chlorantraniliprole-lambda-cyhalothrin mixture was significantly more effective than the one with emamectin benzoate in reducing the attack of T. absoluta on tomato fruits, in both dates of assessments. As concerns damage by S. littoralis on the fruits, at the first assessment, trt. 2 and trt. 5 significantly reduced the percentage of infested berries in comparison with the control, whereas the infestation was not significantly reduced by trt. 3 and trt. 4. At the second assessment, no statistically significant difference between the four different treatments was observed. Since the infestation of tomato fruits by S. littoralis was much lower than the one caused by T. obsoluta, the overall performance of the four insecticide treatments was mainly due to the control effects towards T. obsoluta.