Bio-Efficacy of DOR Bt, a Bacillus thuringiensis formulation against Rice Leaf Folder, Cnaphalocrosis medinalis (Guenee) in Punjab

The studies on bio-efficacy of DOR Bt, a Bacillus thuringiensis formulation against rice leaf folder, Cuaphalocrosis mediualis (Guenee) in Punjab were conducted for three years) during 2005 to 2007, Three dosages of DOR Bt (1.0, 1.5 and 2.0 Kg/ha) were applied on appearance of the pest and were compared with chemical control (monocrotophos 36 SI. @1.4 l/ha) and untreated control. After 45 days of transplanting the lowest mean incidence (1.38%) was recorded in higher dose (2,0 kg/ha) of DOR Bt followed by monocrotophos (l.44%) and incidence in these two was significantly lower than all other treatments. After 60 days of transplanting the lowest mean incidence (1.08%) was observed in monocrotophos, which was significantly lower than all other treatments except higher dose (2,0 kg/ha) of DOR Bt (1.11%), which was also significantly lower than all other treatments. The maximum mean yield (61.12 q/ha) was harvested from monocrotophos which was also significantly higher than all other treatments except higher dose (2.0 kg/ha) of DOR Bt (60,75 q/ha). Significantly lower yield was obtained from control plot (53,81%). It can be concluded that DOR Bt @ 2.0 kg/ha was as effective as monocrotophos 36 St. @ 1,4 l/ha in controlling the rice leaf folder and increasing the grain yield of rice.