Komposisi Spesies Penggerek Batang Padi dan Parasitoid Telurnya pada Ketinggian Tempat yang Berbeda

Composition of Rice Stem Borer Species and Their Egg Parasitoids at Different Altitudes. Rice stem borer is one of the main pest of rice plants that always percolating and attack plants in the field. The pests can result in damage to plants and lost of the grain from season to season. The aim of this research is to know composition and dominance rice stem borer species and role of their eggs parasitoid at an altitude of different places. Research is done by survey based on the height of different altitude in rice plants two weeks after cropping up until eleven weeks after planting. Research conducted from April until August 2019 in rice field that belonging to farmers at Subak Cemagi Let, Cemagi Village and Subak Teba, Mengwi village, Badung regency, Bali province. Subak Cemagi Let are at an altitude of 15 meters above sea level whereas Subak Teba are at an altitude of 300 meters above sea level. Identification of Rice stem borer larvae and their eggs parasitoid done in Pest Laboratory, Agriculture Faculty of Udayana University. Found three species rice stem borer in the height 15 mdpl namely Scirpophaga incertulas; Sesamia inferens dan Chilo suppressalis, whereas in the height 300 mdpl found four species namely Scirpophaga incertulas, Sesamia inferens, Chilo suppressalis, dan Chilo polychrysus. S. incertulas was the most dominant at the two different altitude. Three species of eggs parasitoid that have role to suppress the development of rice stem borer at the different altitude namely Tetrastichus schoenobii, Telenomus rowani dan Trichogramma japonicum. T. schoenobii was the most dominant to suppress rice stem borer populations.

Pheromone Receptors Help Cnaphalocrocis medinalis Avoid Competition in Rice Fields

Cnaphalocrocis medinalis (Guene'e) (Lepidoptera: Pyralidae) is one of the most important insect pests that attack the rice crop, Oryza sativa L., in China, feeding on rice leaves. Chilo suppressalis and Sesamia inferens are two common insects living within the same ecological system that feed on rice stalks. Their behavior could affect C. medinalis's choice of oviposition place, so we tested the electroantennogram (EAG) response of C. medinalis to a conspecific sex pheromone (Z11-18:OH; Z11-18:Ald; Z13-18:OH; Z13-18:Ald) and two other insects' pheromone compounds (Z9-16:Ald; Z11-16Ald; Z11-16:OH;Z11-16:Ac and 16:Ald). The results indicate C. medinalis can detect those pheromones and is sensitive to Z11-16:Ald and Z9-16:Ald. In the heterologous expression system of Xenopus oocytes, we cloned three pheromone receptor genes, CmedPR1, CmedPR2, and CmedPR3. These had the same electroantennogram response, in addition to the response to the conspecific pheromone. CmedPR2 and CmedPR3 displayed strong sensitivity to Z11-16Ald and Z9-16:Ald. These results may contribute to clarifying how C. medinalis recognizes pheromones and interspecies communication.

An Overview of the Bionomics, Host Plant Resistance and Molecular Perspectives of Sesamia inferens Walker in Cereals and Millets

There is an urgent need to enhance agricultural production as well as productivity to meet the food demand of the growing population, estimated to be 10 billion by 2050, using a holistic and sustainable approach. The daily food sources for almost three-fourth of the global population, cereals and millets, are prone to several biotic factors and abiotic pressures. In particular, cereals and millet cultivation are limited by the polyphagous pink stem borer, Sesamia inferens Walker (Lepidoptera:Noctuidae) gaining national importance, since its larvae and pupae are concealed within the stem, none of the management measures have been found effective in controlling the menace. However, host plant resistance (HPR) is a reasonable and ecologically safe method wherein resistance mechanisms of crops could lower the stem borer infestation. The foremost challenge in understanding the mechanism would be to detecting the genes of interest in the crop using novel biotechnological approaches. The fundamental criterion for developing insect-resistant lines relies on recognizing the mechanism of plant resistance. The entire life cycle of this group of borers is completed or hidden within the stem, posing a hurdle in their management. Thus, molecular markers and Quantitative Trait Locus (QTL) mapping offer a more efficient approach to entomologists and plant breeders wherein they can work with traits like QTLs for stem borer resistance. In this review, an attempt has been made to provide an extensive summary of the host range and crop losses due to this borer, besides its taxonomic position, geographic distribution, bionomics, genetics of resistance, and molecular perspectives.

Keragaman Organisme Pengganggu Tanaman (OPT) pada Tanaman Padi Varietas Unggul Baru (VUB) dan Varietas Lokal pada Percobaan Semi Lapangan

Serangan Organisme Pengganggu Tanaman (OPT) pada tanaman padi apabila tidak ditangani dengan serius akan menurunkan produktivitas tanaman secara signifikan. Keragaman OPT yang menyerang tanaman padi varietas lokal dan varietas unggul baru (VUB) sangat penting untuk diketahui agar dapat dilakukan tindakan pengendalian yang lebih efektif dan efisien. Penelitian dilaksanakan pada bulan Agustus sampai Februari 2018, di Teaching Farm Fakultas Pertanian Universitas Hasanuddin Makassar. Metode yang digunakan pada percobaan semi lapangan ini dengan mengamati secara langsung jenis OPT yang menyerang rumpun tanaman padi, gejala serangan yang ditimbulkan serta menghitung persentase serangan. Pengamatan dilakukan setiap hari, dimulai pada saat tanaman berumur ± 30 hari setelah tanam. Hasil penelitian menunjukkan bahwa OPT yang menyerang VUB dan varietas lokal yaitu Locusta migratoria. L, Sesamia inferens, Cnaphalocrosis medinalis serta patogen penyakit hawar daun bakteri (HDB). Persentase serangan tertinggi terdapat pada VUB Inpari 16 dan Inpari 42 yang terserang HDB mencapai 50% sedangkan varietas lokal Kamba yang diamati memiliki reaksi ketahanan yang agak baik terhadap berbagai serangan OPT dengan persentase serangan ≤25%. Serangan Nilaparvata lugens hanya ditemukan pada varietas Inpari 16. Hasil penelitian ini dapat dijadikan referensi dan sumber informasi agar pengelolaan dan tehnik pengendalian dapat dilakukan secara tepat, cepat, efisien dan efektif.