International Journal Of Biology and Biological Sciences Vol. 2(11), pp. 154-159, November 2013 ISSN 2327-3062 ©2013 Academe Research Journals

Full Length Research Paper

Efficacy of imidacloprid, a nicotinoid group of insecticide against the infestation of chilli aphid, Myzus persicae (Hemiptera: Aphididae)

Gopal Das

Department of Entomology, Faculty of Agriculture, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh. E-mail: gopal_entom@yahoo.com.

Accepted 14 October, 2013

Abstract

An experiment was carried out during October, 2012 to January, 2013 in the farmer field, under Boyra union, Mymensingh Sadar Thana, to evaluate the efficacy of imidacloprid (Rally, 20 SL) against chilli aphid, Myzus persicae. Three doses of Rally 20 SL (imidacloprid) namely: 1, 2 and 3 ml/L were evaluated against the nymphs and adults infestation at the flowering and fruiting stage of chilli. Data were collected at 1, 3, 7 and 10 day after insecticides spray. The highest mortality was observed from 3 ml/L both in the leaf as well as in twigs which was followed by 2 and 1 ml/L concentration in comparison with that in the water treated control. Imidacloprid had good knock down effect on aphid’s populations; those were significantly reduced just 1 day after insecticide spray although the highest mortality was recorded from day 3 after insecticide spray. Once sprayed, the action of imidacloprid clearly persisted at least up to the 10th day. In untreated plant, >70% of leaves were found distorted or in a somewhat twisted condition. Following imidacloprid spray, majority of the distorted leaves were backed to normal condition within 10 days after spray (DAS), but no significant changes were observed on 1-7 days after spray although aphid populations were significantly reduced immediately after imidacloprid spray (>80% reduction was observed after the 1st day). The aphid populations were mostly confined on the ventral surface of the leaf than the upper surface. For controlling chilli aphid, Rally 20 SL would be an excellent neonicotinoid insecticide with the dose of 2 ml/L considering the mortality level.

Key words: Chilli, aphid, Myzus persicae, imidacloprid, efficacy, mortality.