Field Evaluation of Insecticides for the Management of Rice Planthoppers, Sogatella furcifera and Nilaparvata lugens

摘要

Rice planthoppers, especially the whitebacked planthopper, Sogatella furcifera (Horvath) and the brown planthopper, Nilaparvata lugens (Stal.) are the major delphacid hoppers attacking rice in tropical Asia. Hopper-burn caused by these planthoppers threatens global rice crops, particularly in Asia (Backus et al, 2005). The brown planthopper alone causes 10-30 per cent loss in rice yield (Li et al., 1996). In India, both the planthoppers are economically important, the brown planthopper (BPH) being more widespread in comparison to the whitebacked planthopper (WBPH). In Punjab, the WBPH is of major economic importance (Shukla and Gupta, ,1991); yield losses as high as 79.8 per cent have been reported (Kushwaha and Singh, 1986). The BPH was not a serious problem in the state until mid-2000 but, during kharif 2007 season, it appeared in serious proportions causing hopper-burn in some districts of the Punjab. Since then, its incidence has started increasing on rice, particularly late in the season. Farmers rely solely on insecticides for management of these planthoppers on rice and basmati crops. Several insecticides in different formulations have been reported effective against these hoppers (Singh et al., 1989; Panda et al, 1995, Varma et al, 2003; Krishnaiah et al, 2004; Kendappa et al, 2005; Wang et al, 2008; and Catindig et al, 2009). Imidacloprid, quinalphos, monocrotophos and chlorpyriphos have been recommended for the control of planthoppers in the State (Anonymous, 2010). The indiscriminate use of insecticides over the years has led to the development of insecticide resistance in planthoppers (Heinrichs, 1994; Liu et al, 2003; Krishnaiah et al, 2006). Keeping in view the economic importance of rice crop and damage potential of these insect pests, the present study was undertaken to compare the efficacy of buprofezin (an insect growth regulator), thiomethoxam and imidacloprid (neonicotinoids) at different dosages with the already recommended insecticide, chlorpyriphos.