Abstract

Myzus persicae Sulzer, 1776 (Sternorrhyncha: Aphididae) is an insect pest of several crops. Chemical control against pests causing harmful effects, so it is necessary to find alternative methods. In this context, insecticidal activity of water and hydroethanol extracts of neem leaves was investigated against the aphid M. persicae through biological performance and feeding behavior assessment. Water and hydroethanol extracts of neem leaves are prepared by soaking ground leaves in water or 10% ethanol overnight. Both water and hydroethanol extracts of neem leaves at 1, 5 and 10% in artificial diet significantly reduced (p < 0.05) the survival of nymphs, leading to more than 95% mortality. Both extracts at 0.1% significantly reduced (p < 0.05) the survival rate and fecundity of M. persicae adults. The feeding behavior of aphids was studied with a dual-choice assay and using the electrical penetration graph (EPG) technique. Dual-choice assays revealed the aphid rejection of the water extract at 10% and the hydroethanol extract at 1 and 5% concentrations. EPG monitoring showed enhanced duration of probing and ingestion on artificial diet containing the water extract at 10%. On plants sprayed with water extract at 10%, EPG monitoring showed reduced duration of probing, delayed phloem access, and reduced salivation and ingestion phases. Our results showed that neem leaves-based preparations are insecticidal agents and effective to control M. persicae.

Key words: Neem leaves extracts, Myzus persicae, survival, feeding behavior.