Evaluation of spray regimes of monocrotophos to control budworm (Earias spp.) damage to seed kenaf (Hibiscus cannabinus L.)Evaluation des regimes d'atomisation de monocrotophes pour regler les vers du bouton (Earias spp.) degats causes aux graines de kenaf (Hibiscus cannabinus L.)

Abstract

The effect of timing of monocrotophos application on its efficacy for the control of budworm, Earias spp. on seed kenaf was evaluated in replicated field trials at Moor Plantation, Ibadan, Nigeria. Monocrotophos was applied at the same rate, three times per season over four different kenaf growth phases and its effect (in time) on budworm attack and damages to young plant shoots, flower and capsules was noted. Results showed that spray applications initiated at 50 per cent flower set stage were as effective as those initiated at the flower bud stage for budworm control. Applications initiated at the flower bud stage gave very low per cent budworm damage (12) and larger kenaf seed yield (1,444 kg ha^-1) as compared to the unsprayed control treatment that gave high per cent budworm damage (25) and smaller kenaf seed yield (672 kg) in the first season. The results of the second season trial followed a similar trend. Similarly, applications initiated at the 50 per cent flower set gave 11 per cent flower bud damage and seed yield of 1453 kg ha^-1 compared to the unsprayed control that gave 27 per cent budworm damage yield of 690 kg ha^-1. From these results, chemical application initiated at the flower bud stage will effectively reduce budworm damage and consequently increase kenaf seed yields.

Keywords: monocrotophos, budworm, Hibiscus cannabinus, spray regimes

Agricultural and Food Science Journal of Ghana Vol. 3 2004: 269-277