Seasonal Abundance and Species Composition of Nephotettix spp., in Endemic and Non-Endemic Areas of Rice Tungro Virus Disease in South Sulawesi Province, Indonesia

Rice tungro disease is semi-persistently transmitted by five species of leafhopper. Nephotettix virescens Distant and N. nigropictus Stal. (Homoptera: Cicadellidae) are predominant species in South Sulawesi with vectoring efficiencies of 83 and 27%, respectively. Relative composition of those species affects the RTV incidence in the field. The purpose of the study was to determine the presence and abundance of those species in RTV-endemic and non-RTV-endemic areas in South Sulawesi. The presence of both species at different altitudinal levels was also determined. The results showed that N. virescens was present in both RTV-endemic and non-RTV-endemic areas. In RTV-endemic area, N. virescens was the only species found. Higher number of N. nigropictus existed in non-endemic area with less intensive use of insecticide than in non-endemic area with intensive use of insecticides. Nephotettix virescens was found in the low (< 100 m above sea level) and mid (500-700 m) altitudes but not in the high elevation (> 1000 m). In the high altitude, only N. nigropictus existed. This species was also present in the mid and lower levels in non-RTV-endemic area with lower intensity of insecticide use.