Acute toxicity and field evaluation of spinetoram 12 SC against Helicoverpa armigera Hubner on tomato

Abstract

A new biological insecticide molecule, spinetoram 12 SC was evaluated in the laboratory to determine acute toxicity on the third instar larvae of tomato fruit borer, Helicoverpa armigera (Hubner). The homogeneity response of H. armigera to different rates of spinetoram12 SC was observed and median lethal concentration (LC50) was 5.20, 3.54 and 1.94 ppm after 24, 42 and 48 h after treatment. Field experiments were conducted and results revealed that application of spinetoram 12 SC at 45 g a.i./ha was significantly superior in minimizing the larval population (77.9 and 80.2% reduction) and fruit damage (80.3 and 81.2% reduction) of H. armigera and in increasing tomato fruit yield (100.5 and 94.4% increase) than indoxacarb 15 SC, novaluron 10 EC and quinalphos 25 EC. There was also minimum to moderate level of toxicity observed due to spinetoram at 45 g a.i./ha against coccinellids predators (9.6 and 5.5% reduction) of tomato ecosystem.