The effectiveness of the entomopathogenic fungus Metarhizium anisopliae in controlling the green leaf hopper (Nephotettix virescens)

Green leafhopper (Nephotettix virescens) is one of the major pests on rice plants that can be a vector of tungro disease. Current pest control using insecticides by farmers is very worrying because in general it is not as recommended which can cause disturbances in the balance of the ecosystem, so it is necessary to use more environmentally friendly control alternatives, one of which is the use of entomopathogenic fungi that are targeted and do not cause the death of natural enemies. The potential of entomopathogenic fungi as biological control agents needs to be continuously developed to reduce the use of insecticides, one of which is the fungus Metarhizium anisopliae which is a type of entomopathogenic fungus that can kill insect pests. The purpose of this study was to determine the effect of several concentration and application method of M. anisopliae on the mortality of the green leafhopper (Nephotettix virescens). The study was conducted in the Laboratory and Greenhouse of the Tungro Disease Research Station starting from February - April 2020 using a two-factor factorial design in a completely randomized design (CRD). The first factor was the application method consisting of two treatments, namely the spray method (A1) and dip method (A2) while the second factor was the conidia density of Metarhizium anisopliae with 4 levels, namely 0 (C0) as control, conidia density 106 (C1) conidia density 107 (C2) conidia density 108(C3). Each treatment was repeated three times. The results showed that the concentration of 106 by dipping application showed the fastest average death time of green leafhopper imago, which occured after 4 days of application, while the fastest average death time of green leafhopper nymph was 3.67 days after application at a concentration of 10 7 by dipping applications.

A comparative study on the insecticidal property of Bambusa vulgaris and Bambusa malingensis shoot and leaf extract against green leafhopper (Nephotettix virescens)

Rice is considered one of the staple foods in Southeast Asian countries, most especially in the Philippines. There are many factors needed to be considered in growing rice crops: the soil nutrient, the climate, the water supply, and the fertilizer used as a supplement to crop growth. But one important thing that farmers should consider is the infestation of pests, specifically the green leafhoppers, which is the primary carrier of tungro virus. This virus affects the growth and development of rice crops. This study aims to investigate the insecticidal effect of Bambusa vulgaris and Bambusa malingensis shoot and leaves extract against green leafhoppers (Nephotettix virescens). The extract was obtained by the decoction method. Phytochemical analysis of the two bamboo species has been carried out, as it was found out that both of them contains alkaloids, flavonoids, and glycosides. The results showed that both the shoot and leaves extract of Bambusa vulgaris and the shoot extract of Bambusa malingensis have potential insecticidal activity against Nephotettix virescens. Further research is needed to identify other factors that could strengthen the effectiveness of applying the extract to the insect specimen.

Hubungan Antara Profil Protein Populasi Vektor Wereng Hijau Nephotettix virescens dan Gejala Penularan Tungro pada Tanaman Padi

Nephotettix virescens is the most effective vector for transmitting tungro disease to rice plants. Two different viral particles cause Tungro transmission. Disease control was often not anticipated in the field, especially when planting is asynchronous, that cause been detected lately. At the cellular level, vector interactions with viruses indicate vector proteins response to viral in the body of vector insects which involved in virus transmission in plants. This study aims to describe the relationship between the differentiation of N. virescens vector protein profiles on the types of tungro symptoms resulting from the transmission to develop techniques for early detection and control of the transmission process. The workflow of this study is screening on vector insects to obtain protein candidates thought to have a role in tungro transmission that had never been previously reported. The results of this study suggested that proteins with estimated molecular weights of 132, 73, and 49 kDa are candidates for proteins that can be used for screening purposes or virulent vector tracing as an early warning alternative to control tungro disease in endemic areas.

PREFERENCE TEST OF GREEN LEAFHOPPER (Nephotettix virescens Distant) TO SOME TUNGRO-RESISTANT PROMISING LINES

Preference test of green leafhopper (GLH) Nephotettix virescens Distant to some tungro-resistant promising lines. Tungro is the most important diseases of the rice plant, caused by two types of viruses, namely Rice Tungro Bacilliform Virus (RTBV) and Rice Tungro Spherical Virus (RTSV), transmitted by green leafhopper (GLH) especially Nephotettix virescens Distant in a semi- persistent manner. The aim of this research was to study some of the varieties dislike (resistant) to GLH and resistant to rice tungro virus. The study was conducted on Januari to August 2019 at Green House of Indonesian Tungro Disease Research Station and at farmer’s field in Polman West Sulawesi. The experiment in the green house was preference and survival test using a Randomized Completely Block Design (RCBD) with three replications. The materials consisted of 48 tungro-resistant promising lines and 2 varieties as a check. The field experiment using an augmented design with four blocks. Every block consisted of 20 promising lines and four varieties of checks (Ciherang, Tukad Unda, Inpari 9 Elo, and IR 64). Variables observed were the number of GLH present and survival in promising lines, the population of GLH at the field, the percentage of tungro incidence, the filled with spikelet number, the unfilled of spikelet number, the weight of 1000 grain, and the grain yield at 14% moisture content. The results showed that ten promising lines was dislike (resistant) to GLH and resistant to rice tungro virus with the percentage of tungro incidence lower or equal than resistant check varieties (Inpari 9) and had high yield potential (6,2 – 10,2 t/ha).

Komunitas serangga hama padi rawa lebak yang ditanam dengan berbagai jarak tanam

Jarak tanam padi mempengaruhi spesies dan populasi serangga hama. Jarak tanam lebih rapat ideal untuk habitat dan relung serangga hama. Penelitian ini bertujuan untuk mengobservasi perbandingan komunitas serangga hama padi rawa lebak yang ditanam dengan berbagai jarak tanam. Percobaan lapangan dilaksanakan pada padi di lahan rawa lebak seluas 15 ha yang ditanam dengan jarak tanam tegel (25 cm x 25 cm) dan jajar legowo pada berbagai kombinasi jarak (4:1, 5:1, 6:1, dan 7:1). Serangga hama diambil menggunakan jaring serangga. Semua spesies serangga hama yang ditemukan pada satu musim tanam padi pada penelitian ini adalah 27 spesies. Spesies yang dominan ditemukan pada padi fase vegetatif adalah Oxya chinensis (Thunberg), Acrida turrita (Linnaeus), Nilaparvata lugens (Stål), Nephotettix virescens (Distant), dan Cofana spectra (Distant), sedangkan pada fase generatif didominasi oleh Leptocorisa acuta (Fabricius) dan Riptortus sp. Populasi N. lugens dan N. virescens tidak dipengaruhi oleh jarak tanam. Populasi kedua jenis wereng tersebut rendah dan tidak menjadi hama utama di padi rawa lebak. Spesies serangga hama utama adalah L. acuta dan populasinya dipengaruhi oleh jarak tanam padi. Populasi hama lebih tinggi pada padi dengan jarak tanam yang lebih rapat, yaitu jajar legowo 6:1, 7:1, dan tegel dibandingkan dengan jajar legowo 4:1 dan 5:1. Untuk itu, jajar legowo 4:1 atau 5:1 sebaiknya diterapkan di sawah rawa lebak untuk menekan populasi fitofag agar tidak menjadi hama penting.