Evaluasi Konsentrasi Lethal dan Waktu Lethal Insektisida Botani Terhadap Ulat Bawang (Spodoptera exigua) di Laboratorium

Abstract

<p><strong>[Evaluation of Lethal Concentration and Lethal Time of Botanical Insecticide Against Beet Armyworm (<em>Spodoptera exigua</em>) in The Laboratory]</strong></p><p>Pemanfaatan insektisida botani merupakan salah satu pilihan untuk mengendalikan serangan hama Spodoptera exigua yang ramah lingkungan. Tujuan penelitian adalah untuk menetapkan konsentrasi sublethal dan waktu prolethal insektisida botani terhadap larva instar ketiga S. exigua di laboratorium. Percobaan dilaksanakan di Laboratorium Entomologi Balai Penelitian Tanaman Sayuran di Lembang ( ± 1.250 m dpl.), mulai bulan Mei sampai Desember 2015. Penelitian menggunakan metode pencelupan serangga. Mortalitas larva S. exigua diamati mulai 1, 3, 6, dan 12 jam setelah perlakuan dan diulang setiap 24 jam sampai 96 jam. Data mortalitas larva diolah menggunakan analisis probit untuk menetapkan nilai LC50 dan LT50. Hasil penelitian menunjukkan bahwa mortalitas larva S. exigua paling tinggi terjadi pada saat 96 jam setelah perlakuan ekstrak bintaro (85,0%), diikuti oleh ekstrak akar tuba (82,5%), dan yang terendah diperoleh dari hasil aplikasi ekstrak huni yang hanya dapat mematikan larva S. exigua sebesar 57%. Dari lima ekstrak tumbuhan tersebut, nilai LC50 terendah diperoleh dari ekstrak daun bintaro (1.002,67 ppm), diikuti oleh ekstrak daun akar tuba (1.256,07 ppm), ekstrak kirinyuh (1.304,37 ppm), ekstrak suren (1.307,37 ppm), dan tertinggi diperoleh dari ekstrak huni (3.316,06 ppm). Waktu kematian 50% (LT50) S. exigua yang terpendek terjadi pada 33,50 jam dengan fiducial limit 23,24 – 48,42 jam untuk ekstrak daun akar tuba, sedangkan waktu kematian 50% (LT50) S. exigua yang terpanjang diperoleh dari ekstrak daun huni, yaitu 136,52 jam dengan fiducial limit 76,47 – 234,51 jam. Dari penelitian ini diketahui bahwa insektisida botani menunjukkan efikasi yang tinggi terhadap larva S. exigua sehingga dapat direkomendasikan sebagai komponen untuk pengendalian hama terpadu (PHT).</p><p><strong>Keywords</strong></p><p>Bawang merah; Mortalitas; Insektisida botani; LC50; LT50 </p><p><strong>Abstract</strong></p><p>Utilization of botanical pesticides is one option of environmentally friendly methods to control the attack of Spodoptera exigua . The objective of this study was to evaluate of lethal concentration and lethal time of plant extracts as botanical insecticide against third instar larva of beet armyworm, S. exigua under laboratory condition. The experiment was conducted at Indonesian Vegetables Research Institute at Lembang (±1,250 m asl.), from May to December 2015. Insect dipping method was used in this research. Mortality of S. exigua larvae was observed at 1,3,6, and 12 hours after exposures to the plant extracts and repeated every 24 hours up to 96 hours of exposures. The results of the experiments showed that at 96 hours post treatment, the highest mortality (85.0%) of the S. exigua larvae was caused by sea mango extract followed by Derris leaf extract (82.5%) and the lowest mortality of S. exigua larvae (57%) was obtained from spreng extract. The lowest LC50 from five of the extracts of botanical insecticide derived from sea mango leaf extract (1,002.67 ppm) followed by Derris leaf extract (1,256.07 ppm), Eupatorium leaf extract (1,304.37 ppm), Toona leaf extract (1,307.37 ppm), and the highest LC50 derived from spreng leaf extract (3,316.06 ppm). The shortest of the mean lethal time 50 (LT50) values of S. exigua was 33.50 hours obtained from Derris leaf extract with fiducial limits 23.24–48.42 while the longest of the mean (LT50) values of S. exigua was 136.52 hours obtained Spreng leaf extract with fiducial limits 76.47–234.51 hours. The botanicals insecticides were proven to be effective against S. exigua larvae, so it can be recommended to be used as components for integrated pest management (IPM).</p>

In-vitro effectiveness test of leaf extract of cattapa and derris to control anthracnose in chili

“…According to Maini and Rejesus [24], leaf extract of derris contains active compounds, such as dequelin (0.15 -2.9%), eliptone (0.35 -4.6%) and toxicarol (0 -4.4%). While Hasyim et al [21] found that from the results of GC-MS analysis, leaf extract of derris contained 7-isopropensil-1, 4a dimethyl-4, 4a, 5,5,7,8hexahydro-3 H-naphthalen-2-0 ne, squalen2 , ergosi-5-en-3-ol, compesterol stigmasterol, rotenone, gamma-sitosterol, 2,3,6-trimethoxy-5-methylphenol, and n-hexadeconoic acid. Based on these contents, it is possible that there are active ingredients that greatly affect the suppression of C. capsici pathogens.…”

“…The use of leaf extract of derris for pest control has been widely practiced. Hasyim et al [21] has evaluated of leaf extract of derris on concentration and lethal time in onion caterpillar (Spodoptera exigua) in the laboratory. Meanwhile, leaf extract of derris for disease control have been tried against Fusarium oxysporum [22].…”

Potensi Daun Lamtoro (Leucaena leucocephala) Sebagai Biopestisida Ulat Grayak (Spodoptera litura F.)

“…Enzim protease akan menurun akibat adanya aktivitas saponin serta dapat mengganggu penyerapan makanan (Chaieb, 2010;Kuddus et al, 2011). Masuknya saponinke dalam tubuh larva mengakibatkan terganggunya sekresi enzim pencernaan, dengan tidak adanya enzim pencernaan maka metabolisme pencernaan akan terganggu, sehingga akan mengakibatkan larva mati karena kekurangan nutrisi untuk kelangsungan hidupnya (Hasyim et al, 2019). Mekanismekerja dari senyawa saponin ialah sebagai stomach poisoning pada ulat dengan cara saponin akan menurunkan tegangan permukaan selaput mukosa traktus digertivus ulat sehingga dinding traktus digestivus menjadi korosif.Saponin juga menyebabkan iritasi lambung apabila dimakan (Utami, 2010).Adanya senyawa saponin diduga juga menyebabkan ulat grayak mengalami gagal melakukan pergantian kulit (molting) (Gambar c).…”

In Vitro Test on the Effectiveness of Citrus limon and Allium sativum as Pediculicides

“…Phytochemical test results showed that essential oils contain secondary metabolites in the form of alkaloids, terpenoids, and tannins (4). Toxic alkaloids and nerve poisons are alkalic substances and contain one or more nitrogen atoms (24). The research results conducted by Samilati, et al (4) showed that the death of mosquito larvae given Allium sativum solution was through four phases, namely stimulation (changes in larval behavior from normal circumstances), convulsions, paralysis, and ended with death.…”

“…Tannins found in Citrus limon and Allium sativum are toxic, have a bitter taste, and have an antifeedant effect (23). Tannins play a role in disrupting the process of absorption of proteins needed for growth by binding to proteins in the digestive system of insects (24).…”