Factors affecting the feeding behaviour of Nephotettix virescens (Distant), a vector of rice tungro virus disease

Intensity of xylem and phloem feeding of Nephotettix virescens (Distant), an important vector of rice tungro virus (RTV) disease, was measured in three rice varieties having different levels of resistance against the GLH and RTV. The pest was exposed to two temperatures (30±1°C and 17±1°C) and light conditions (day and night time) using a caged method in the laboratory. The green leafhopper (GLH) fed more at 30±1°C than at 17±1°C and also during the day time. Varieties like TN-1, IR-36 and IR-50 differed in respect of xylem and phloem feeding. More feeding on xylem tissues by leafhopper was observed on IR-36 and IR-50, while more phloem feeding on TN-1 both in respect of temperature and light variations. A significant relationship, however, was observed between the varieties, temperature and their interaction in relation to phloem feeding only. IR-64 revealed the highest xylem feeding area (159.5 mm²). But, it was minimum in IR-26 (29.2 mm²) with maximum survival (6.4 days) and the highest infection up to 85.7 per cent. This suggested susceptibility of IR-26 to both the virus and vector. Cultivar Vikramacharya showed high amount of xylem feeding (106.8 mm²) and low GLH survival (9.8 days) with 30.0 per cent virus transmission.