EVALUATION OF NONCHEMICAL MANAGEMENT PRACTICES AGAINST BROWN PLANT HOPPER, NILAPARVATA LUGENS (STAL.) (HOMOPTERA: DELPHACIDAE)

Abstract

The investigation was made to evaluate the effectiveness of nonchemical management practices against brown plant hopper (BPH), Nilaparvata lugens (Stal.). The treatments of the cultural practices were three different levels of Urea fertilizer application and three different seedling spacing. The experimental results showed that the number of BPH was increased with the increased of days after transplanting in both treatments. The highest number of nymphs and adults were recorded at maximum doses (225 kg/ha) of urea fertilizer application and closer seedling spacing at 75 day after transplanting while the lowest number was observed in minimum doses with maximum wider seedling spacing at 30 days after transplanting in both locations. The methanol solvent extracts at 0.5, 1.0 and 1.5 % concentration of six plants were evaluated for their toxic effects against nymph and adult of brown plant hopper. The results revealed that all six plant extracts had different toxic effects against BPH. Chili plant extract showed the highest toxic effect whereas castor showed the lowest toxic effect against both the nymphal and adult stages. Mortality percentage was also found directly proportional to the level of concentrations of plant extracts and to the exposure period. All the doses of six tested plant extracts were found to be excellent mortality of both the nymph and adult at different time intervals (30, 45, 60 and 75 DAT) and were effective at higher dose. The lowest LD50 value also indicated that the chili leaf extract is highly effective against the nymph and adult of BPH. The results clearly indicate that the plant based pesticide containing low lethal concentration can be used effectively to control the BPH. Key words: Urea fertilizer, spacing, plant extract, methanol, mortality, BPH.