Effect of dates of sowing, fertilizer levels and varieties on the incidence of top shoot borer (Cydia tricentra Meyr.) of sunnhemp (Crotalaria juncea Linn.)

Effect of dates of sowing, fertilizer levels and varieties on the incidence of top shoot borer, Cydia tricentra Meyr. and its effect on fibre yield in sunnhemp were studied for four years (1994–1997). The infestation of top shoot borer was significantly less in April sowing and the fibre yield increased significantly in April sowing during all the years. Effect of different levels of fertilizers and varieties on the incidence of top shoot borer was statistically insignificant. All the interactions between dates of sowing, fertilizer levels and varieties on pest incidence were insignificant in all the years. However, higher dose of fertilizer (N10 P20K20) increased the pest infestation from 4.60–8.30 per cent over control where no fertilizer was applied, and variety K-12 yellow showed marginally less infestation over K-12 Black and Chindwara. The effect of fertilizers on fibre yield was significant in 1996 and 1997, while the effect of varieties on fibre yield was significant in all the years except in 1994.