Toxicity and Efficacy of Chlorantraniliprole on Pieris rapae (Linnaeus) (Lepidoptera : Pieridae) on Cabbage

 Encore une voie de recherche pour ce produit qui est autorisé en période de floraison pour les abeilles. En action contre les larves d’un lépidoptère comme le papillon paysandisia. Réputé aussi efficace que Spinosad et indoxacarbe et beaucoup plus qu’Emamectine benzoate ( pourtant présentée comme remède miracle). Le chlorantraniliprole est une substance active de produit phytosanitaire de la famille chimique des diamides anthraniliques, qui présente un effet insecticide. Son mode d’action consiste à surstimuler les muscles des insectes en déclenchant l’activation des récepteurs de ryanodine. Cette altération de la régulation musculaire épuise les réserves de calcium présent dans les fibres musculaires et conduit à la paralysie, puis à la mort de l’insecte. Cet insecticide est efficace notamment sur les lépidoptères des cultures fruitières et légumières, contre l’eudémis et la cochylis sur la vigne, contre la pyrale du maïs et contre le doryphore sur pomme de terre, tomate et aubergine. il est présent dans de nombreux produits agréés en France avec la mention pour la plupart "Emploi autorisé durant la floraison (abeilles)" C’est aussi l’occasion pour SNP, de lancer un nouvel appel à FREDON PACA pour l’organisation d’une réunion de travail autour des traitements biologiques (http://www.sauvonsnospalmiers.fr/spip.php?article1602). Nous voulons vérifier pour ce produit comme sur d’autres qu’il suffirait d’une extension d’usage pour augmenter l’arsenal anti paysandisia.

Abstract Toxicity of chlorantraniliprole was assayed against young (first and second instars) and older larvae (third and fourth instars) of cabbage Pieris rapae (Lepidoptera : Pieridae) on cabbage (Brassicae oleracea), and persistence of field–aged leaf residue of chlorantraniliprole was assayed with 5-old-day larvae of P. rapae on cabbage. Efficacies of chlorantraniliprole and other newer insecticides to P. rapae were tested under field conditions for two seasons in Hubei province in China. The LC50 value of chlorantraniliprole for early and later P. rapae larvae were 7.92 and 11.34 mg/L by contact toxicity, respectively. The LC50 value of chlorantraniliprole for early and later P. rapae larvae were 0.95 and 4.32 mg/L through ingestion, respectively. The toxicity of field-aged leaf residues of chlorantraniliprole (0-, 3-, 5-, 7-, 10-, 14-, 21-, 25-, and 28-day-old residues) declined gradually under the field conditions. Almost all larvae died on day 5 after feeding on the leaves with 0-21-day residue, and the mortalities were as high as 83.3% and 72.5% for the 21- and 25-day-old leaf residues. Chlorantraniliprole application suppressed P. rapae larvae below the economic threshold for 21-28 days. The field efficacy trials show that chlorantraniliprole at 52 mg a.i /L rate was effective against P. rapae larvae on cabbage, providing marketable cabbage with three applications per season. In addition, chlorantraniliprole was as effective as indoxacarb and spinosad and significantly more effective than emamectin benzoate. conclusions : 5. Conclusions
Based on both larval densities and plants damage evaluations, chlorantraniliprole, indoxacarb and spinosad were the most effective insecticides against P. rapae on cabbage. Although emamectin benzonate significantly reduced larval densities below the untreated check, they often did not perform as well as the other new products being evaluated. In conclusion, chlorantraniliprole is highly toxic to P. rapae larvae not only through ingestion but also through the cuticle. Its effectiveness under field conditions persisted up to 25 d after treated, and the residue will likely last longer than 25 d. Although biological and other bio-rational methods could play important roles in managing P. rapae, it is normally difficult to produce cabbage and other leaf vegetable for fresh market, with the necessary cosmetic quality and low cull rate, without using insecticide to control pests. Chlorantraniliprole and the newer insecticide evaluated in our field trials represent valuable new chemical control tools that provide growers with alternative to currently used insecticides.

* Journal of Agricultural Science ; Vol. 9, No. 2 ; 2017 ISSN 1916-9752 E-ISSN 1916-9760 Published by Canadian Center of Science and Education Authors Qi Su, Hong Tong, Jiaxu Cheng, Guohui Zhang, Caihua Shi, Chuanren Li, Wenkai Wang