Utilizing Organic Waste for Biopesticide: Efficacy and Mortality Test against <i>Spodoptera litura</i> with Entomopathogenic Microorganisms

Abstract

Spodoptera litura is an agricultural pest that attacks almost all types of herbaceous plants, especially vegetable commodities. Spodoptera litura causes serious damage during the immature or larval stage. The attack of Spodoptera litura larvae can cause significant losses to farmers. To deal with these pests, they still use chemicals that have a negative effect on the environment. Therefore, a good solution is required by utilizing biological agents to control agricultural insect pests. It is an alternative strategy that is more environmentally friendly than the use of chemical pesticides. Research on the use of biocontrol agents as biological control agents for insect pests is still being pursued, one of which is the use of entomopathogenic microorganisms. Biological control using entomopathogenic bacteria is an alternative strategy that is effective and environmentally friendly compared to the use of synthetic insecticides. This study aims to determine the mortality rate from the use of organic waste and bacteria against pathogenic pests Spodoptera litura and to determine the activity of pathogenic pests Spodoptera litura after treatment. This study begins with observations to determine the log phase of bacterial growth by culturing bacteria. The tested bacterial cultures were grown on nutrient broth media so that the bacteria were observed and counted using a hemocytometer method to determine the contact time. The next step was to make nutrient broth liquid media and sterilize using an autoclave at 121°C for 15 minutes. Prepare organic waste of coconut water and 10% molasses to be contacted between the substrate and bacteria. Spodoptera litura was collected from Keputran Market Surabaya - Indonesia every day. Spodoptera litura was treated with biopesticide and mustard greens once at t = 0 hours and the activity and mortality rates were observed at 4 hours, 24 hours, 48 hours, and 72 hours. The results showed that the best variable in % mortality was the consortium of bacteria Bacillus thuringiensis, Bacillus cereus, Pseudomonas fluorescens, and the bacterial community of Sidoarjo mud and a mixture of organic waste coconut water with a pathogenicity value of LT50 for 22 hours and mortality rate at 100%.