Phytochemical Content and Insecticidal Activity of Oil Palm Solid Waste Liquid Smoke

Abstract

Indonesia is one of the countries that relies on palm oil as a source of state income. However, palm oil waste has not been utilized optimally. Liquid smoke is one of the products that can be utilized from palm oil solid waste to control pests and diseases with many chemical compounds. This study aims to determine the content of chemical compounds in palm oil solid waste (fronds, mesocarp fiber, and shells) and the level of effectiveness against pests. Phytochemical analysis was carried out to determine the content of chemical compounds in our several liquid smoke. The solutions (liquid smoke) were analyzed by using UV-vis spectrophotometer and GC-MS. The experiment of liquid smoke against Spodoptera frugiperda was carried out by leaf-residual feeding method. Experiments on the effect of storage on toxicity were also carried out by testing liquid smoke fibers stored for 3 months (L). Leaf feeds (sized 4 x 4 cm) were dipped in a liquid smoke solution with a concentration of 0% (control); 2.5%; 5%; 7.5%; and 10% that mixed with emulsifier tween 80 (0.5 ml/l). The parameters observed in this experiment were the test larvae's mortality, the feed consumption area, the pupae's weight, and the larval stages' development time. Our research showed that the highest compounds in shell, fronds, and mesocarp fiber of palm oil waste liquid smoke were carboxylic acid derivatives (esters), phenols, alcohols, and furans, respectively. Liquid smoke originating from the fronds with a concentration of 7.5%, 10%, and fibers with a concentration of 10% cause the mortality of S. frugiperda larvae by 70%, 62.5%, and 60% respectively. Liquid smoke (from fronds, mesocarp fiber, and shells) also reduces feed consumption by 31-65% at a concentration of 10%.  Meanwhile, the liquid smoke provided did not affect the development time and weight of the pupa. Thus, palm oil solid waste liquid smoke can be used as an alternative for pest control and a solution for utilizing waste.