Efektivitas Asap Cair Tempurung Kelapa terhadap Pengendalian Ulat Bawang Spodoptera exigua (Hubner)

Abstract

Shallots (Allium cepa L.) are a group of root crops that have high economic value. Shallot production in Indonesia according to the Central Bureau of Statistics (BPS) records for 2022 is 1.97 million tons, this number is down compared to the previous year which reached 2 million tons. Spodoptera exigua (Hubner) is one of the main pests in shallot cultivation that attacks the leaves. Damage caused by S. exigua caterpillar attacks can cause a decrease in production and even a significant loss of yield. One alternative that can be used to control S. exigua caterpillars to replace chemical pesticides is liquid smoke from coconut shells. The purpose of this study was to determine the effectiveness of coconut shell liquid smoke on the mortality of S. exigua shallot caterpillar pests as well as biological observations of S. exigua. The results of this study are expected to provide information to farmers about the benefits of using coconut shell liquid smoke as shallot caterpillar control. The research was conducted from May 2022 to January 2023 located in Banjarmlati, Mojoroto District, Kediri City. Research preparations included field observations, preparation of tools and materials, propagation of S. exigua as a test insect, and preparation of coconut shell liquid smoke. While for the research phase, coconut shell liquid smoke was tested on S. exigua with a concentration level of 0%, 1%, 3%, 5%, 7%, and 9%. Observations were made 7 days after the application of coconut shell liquid smoke to observe its effect on the mortality and larval biology of S. exigua. The experiment used a non-factorial Completely Randomized Design (CRD) and significant differences between treatments were tested using the DMRT (Duncan Multiple Range Test) with a 5% confidence level. The results of the analysis of variance showed that the mortality of S. exigua larvae treated with coconut shell liquid smoke was not significantly different compared to the control, except for the 4th day after application. However, giving coconut shell liquid smoke was not effective in causing test larvae mortality of up to 50%. While the results of biological observations showed that the concentration of coconut shell liquid smoke given to each treatment affected the average number of pupae and imago formed. Each liquid smoke concentration had a very significant effect on the number of pupae and imago S. exigua. Treatment with 9% liquid smoke gave the lowest average pupa and imago values among the other treatments with both values of 0.75. However, the treatment was not significantly different from the 5% and 7% concentration treatments. It is known that giving liquid smoke with the highest concentration (9% liquid smoke) can extend the life of the pupae up to 9 days until the pupae finally form imago, longer than the pupal age in the control with a phase of 7.50 days until they form imago. Coconut shell liquid smoke has the potential as an antifeedant against Spodoptera exigua larvae.