Evaluation of some novel insecticides, biopesticides and their combinations against peach leaf curl aphid, Brachycaudus helichrysi infesting nectarine

Aim: Nectarine (Prunus persica var. nucipersica) is an upcoming stone fruit crop in mid hills of Western Himalayas. Peach leaf curl aphid, Brachycaudus helichrysi (Kaltenbach) is a major regular pest which causes around 50 % crop yield loss. Some biopesticides/plant products and neonicotinoids were evaluated against peach curl aphid, B. helichrysi in the present study. Methodology: Two sprays of neonicotinoids namely, imidacloprid and thiamethoxam (both @0.008% and 0.016%), biopesticides viz. Econeem 10000 ppm (0.01 and 0.02% a.i), neem oil (1 and 2%) were applied on nectarine trees twice (once at pink bud stage followed by at fruit set stage) in different combinations in a Randomised Block Design alongwith a recommended insecticide (oxy-demeton methyl @0.025%). In one of the treatment only winter pruning was carried out and no pesticide was applied. The observations on infestation and aphid count was recorded after 7, 14 and 21 days of second foliar application. The avoidable loss and benefit cost ratio were also calculated. Results: Foliar applications of imidacloprid and thiamethoxam (both @0.008%) at pink bud stage followed by spray of oxy-demeton methyl at fruit set stage were found most effective (<10% infestation) in comparison to 55.56 % infestation in control where only water spray was applied. The biopesticides /plant products did not prove effective. Three fourth winter pruning of one year growth was found superior over biopesticides treatments and control. The avoidable loss in the effective treatments was appreciable and the benefit cost ratio was more than 40:1. Interpretation: The combination based on Neonicotinoid treatments i.e. imidacloprid or thiamethoxam (both @0.008%) followed by oxy-demeton methyl (0.025%) were effective both from bioefficacy and economic points of view in managing (Bra chycaudushelichrysi) infestation in nectarines. [GRAPHICS] .