Effects of Insecticides on Voracity of Menochilus sexmaculatus in a Prey Plant System

Abstract

Zigzag ladybird, Menochilus sexmaculatus (Coleoptera: Coccinellidae) is a common predator that feeds aphids, whiteflies and mealy bugs. Insecticides are the dominant tool to manage the pest population, but they have a negative impact on non-targeted organisms. Thus, present study focused on impact of different insecticides on the predatory consumption of 4^th larval instar, male and female of M. sexmaculatus, mortality rate of aphids and foraging behavior between predator and prey in a treated plant system. The experiment was set using Completely Randomized Design (CRD) with five replications. There were two insecticides used along with control, i.e., T1: Abamectin (1.0 ml/ 500 ml water), T2: Acetamiprid (1.0 ml/500 ml water) and T3: Control (500 ml water). The results revealed that the maximum mean consumption was recorded in T2 (Acetamiprid) on 4^th larval instar (26.2), male (27.4) and female (28.6) stages of M. sexmaculatus at 24 Hours After Spray (HAS) followed by T1 (Abamectin), respectively. Similarly, the highest aphid mortality percentage was observed in T1 (Abamectin) during predatory efficiency of 4^th larval instar (48%), male (43%) and female (45%) stages of zigzag beetle at 24 HAS as compared to T2 (Acetamiprid), respectively. Furthermore, the maximum mean foraging behavior between predator and prey was observed in T2: Acetamiprid during 24 HAS followed by T1: Abamectin, respectively. In T3 (control), the highest mean predatory consumption, aphid mortality percent and foraging behavior between predator and prey was observed at 24 HAS followed by 2 and 6 HAS, respectively. The analysis of variance showed significant differences (P<0.05) between various treatments and intervals. Overall, the maximum mean consumption and predator prey interaction was recorded in T2 (Acetamiprid), however the highest aphid mortality percentage was seen in T₁ (Abamectin), respectively.