The efficacy of seed extract of Tephrosia vogelii and Annona squmosa on larvae of Helicoverpa armigera

Abstract

Abstract. Nenotek PS, Ludji R. 2020. The efficacy of seed extract of Tephrosia vogelii and Annona squmosa on larvae of Helicoverpa armigera. Trop Drylands 4: 5-9. Corncob borer (Helicoverpa armigera) is important pest of corn, urging the use of insecticide for its eradication. While using chemical insecticides is not sustainable, the use of plant-based insecticides is thus recommended. This study aimed to determine the efficacy of Annona squamosa and Tephrosia vogelii seed extract mixture on the mortality of 3rd instar larvae of Helicoverpa armigera. A range of concentration, as treatments, were evaluated, i.e., 0.05%, 0.11%, 0.28%, 0.65%, 1.5% and a control (water only) applied with three replicates in each treatment. Ten larvae of H. armigera at each treatment were infested in baby corn, using the residue method. Mortality was observed at 24, 48, 72, 96, and 120 hours after treatment (HAT). Percent mortality of the 3rd instar of H. armigera larvae was analyzed using Probit Polo PC, then proceed with mixed activity analysis. The results showed that the mixture of A.squamosa + T. vogelii seeds extracts killed H. amigera larvae with the value of LC50 and LC95 of 0.07% and 2.07%, respectively. A mixture of A. squamosa seeds + T. vogelii seeds extract was synergistic to H. armigera larvae with combined index values at LC50 and LC95 were 0.53 and 0.58, respectively. Thus, the use of a mixture of A. squamosa seed extract and T. vogelii seed is more efficient because the raw materials used were less at low concentrations to control H. armigera larvae than the extract applied separately.