Pengendalian Hama dan Penyakit Utama Tebu (Saccharum officinarum L.) di PT PG Rajawali II Jatitujuh Majalengka

ABSTRACTPest and disease monitoring aim to determine the type, sign/symptoms, and intensity of attacks. The rat (Bandicota indica), stem borer (chilo sacchariphagus Bojer), and shoot borer (Scirpophaga excerptalis Walker) place major constraints on a sugarcane plantation in PT PG Rajawali Jatitujuh Majalengka districts. The intensity of attacks (IS) of these pests reached 8.6%, 1.26%, and 0.86%, respectively. The intensity of rats reached as high as more than 5%. Shoot borer and stem borer attack are low under 5%. The smut disease caused by the fungus Ustilago scitaminea Sydow with an attacking intensity of 1.53% and belongs to the low category. Integrated pest and disease control include technical, physical / mechanical, biological, and chemical culture. ABSTRAKMonitoring hama dan penyakit bertujuan untuk mengetahui jenis, gejala, insidensi serangan dan cara pengendaliannya. Hama utama tebu di PT PG Rajawali II Jatitujuh Majalengka yaitu hama tikus wirok (Bandicota indica Bechstein), penggerek batang tebu/stem borer (Chilo sacchariphagus Bojer), dan penggerek pucuk tebu/shoot borer (Scirpophaga excerptalis Walker). Insidensi serangan (IS) masing-masing mencapai 8,6%, 1,26% dan 0,86%. Insidensi serangan hama tikus tergolong tinggi dengan standar ambang batas ekonomi yang ditentukan yaitu 0%. Insidensi serangan hama penggerek tebu termasuk kategori ringan yaitu di bawah ambang ekonomi 5%. Penyakit utama yaitu luka api/cambuk jelaga yang disebabkan jamur Ustilago scitaminea Sydow dengan insidensi serangan 1.53% dan termasuk kategori ringan. Pengendalian hama dan penyakit dilakukan secara terpadu meliputi kultur teknis, fisik/mekanis, biologi dan kimia.

Transcriptome Characterization and Expression Analysis of Chemosensory Genes in Chilo sacchariphagus (Lepidoptera Crambidae), a Key Pest of Sugarcane

Insect chemoreception involves many families of genes, including odourant/pheromone binding proteins (OBP/PBPs), chemosensory proteins (CSPs), odourant receptors (ORs), ionotropic receptors (IRs), and sensory neuron membrane proteins (SNMPs), which play irreplaceable roles in mediating insect behaviors such as host location, foraging, mating, oviposition, and avoidance of danger. However, little is known about the molecular mechanism of olfactory reception in Chilo sacchariphagus, which is a major pest of sugarcane. A set of 72 candidate chemosensory genes, including 31 OBPs/PBPs, 15 CSPs, 11 ORs, 13 IRs, and two SNMPs, were identified in four transcriptomes from different tissues and genders of C. sacchariphagus. Phylogenetic analysis was conducted on gene families and paralogs from other model insect species. Quantitative real-time PCR (qRT-PCR) showed that most of these chemosensory genes exhibited antennae-biased expression, but some had high expression in bodies. Most of the identified chemosensory genes were likely involved in chemoreception. This study provides a molecular foundation for the function of chemosensory proteins, and an opportunity for understanding how C. sacchariphagus behaviors are mediated via chemical cues. This research might facilitate the discovery of novel strategies for pest management in agricultural ecosystems.

Toxicity of Barringtonia asiatica Seed Extract Against Chilo sachariphagus

Barringtonia asiatica is one of the plants that the seeds extracts has insecticidal properties. However, the bioactivity of this seed extract has not been tested against Chilo sacchariphagus larvae which is the main pests in sugar cane. The treatment was carried out at several levels of concentration of methanolic seed extract of B. asiatica. The 15 cm of fresh sugarcane shoot dipping into the extract solution in some second. After the solution of extract on the sugarcane shoot dried, the first instar of larvae infested to the sugarcane shoot and then put into 20 cm test tube with 3 cm of diameter. The duration of feeding on treated sugarcane shoot was two days and on the following day the larvae were fed on sugar cane shoots until the survived larvae reached the 5th instar. The results of the experiment indicated that B. asiatica seed extract was toxic to C. sacchariphagus with an LC50 value of 0.398% at 16 days after treatment. Besides toxic, B. asiatica seed extract also has atifeedant activity, and inhibits the growth of immature of C. sacchariphagus in all tested concentrations.Keyword: Toxicity, antifeedant, lethal concentration, Barringtonia asiatica, Chilo sachariphagus