The utilization of organic adjuvants to increase the effectiveness of chlorpyrifos insecticides against Spodoptera litura

Abstract

Public awareness of consuming healthy food with minimal pesticide residues has been on the rise. By contrast, farmers still rely on synthetic chemical pesticides to control pests. The shift from synthetic chemical insecticides to botanical insecticides or bioinsecticides is quite complex, especially in Indonesia. Farmers must have the appropriate technology to be independent of synthetic chemical insecticide. This study aims to test the effectiveness of organic adjuvants to increase the effectiveness of insecticides coupled with chlorpyrifos as an active ingredient. We tested the organic adjuvants containing sulfur, acetic acid, NaCl and aqueous extract of Azadirachta indica leaves. The test involved mustard (Brassica juncea (L.) Czern.) plant on land with a high record of S. litura attacks. The study followed a randomized block design with 8 treatments and 5 blocks, with each block consisting of 20 test plants. The treatments involved water control, chlorpyrifos insecticide at recommended concentration, and a combination of chlorpyrifos insecticide and organic adjuvant. The results showed that the combination of insecticides and organic adjuvants did not have a negative impact on mustard growth, as evinced by the absence of significant difference in all treatments. Furthermore, the combination of insecticides and organic adjuvants reduced the rate of plant damage, the population of S. litura and the population of other insect pests. On the other hand, the combination of insecticides and organic adjuvants did not significantly affect the number of beneficial insects compared with treatment without insecticides. The study documented that the combination of 40 mL L-1 organic adjuvant + 1.8 mL L-1 insecticide chlorpyrifos led to the best results. This combination is found the most effective in reducing plant damage and pest population, without any negative impact on beneficial insects. This study has proven the value of organic adjuvants coupled with chlorpyrifos as the active ingredient to reduce the use of insecticides.