Effect of chemical control of insects at three growth stages on the yield parameters of Kenaf (Hibiscus canabinus L.) in Nigeria
ABSTRACT: Three sprays of a synthetic pyrethroid, Polytrin 440 EC (cypermethrin + protonenofos) were applied fortnightly to control insect pests at the vegetative, flowering and fruiting stages of Kenaf. These
correspond to 2-6,6-10 and 10-14 weeks after planting (WAP). Data gathered included the number capsules damaged by both bollworms and sap-sucking insects. At harvest, data were collected on capsules, fibre and seed yield as well as stem length and diameter (butt). The plants protected only at the vegetative stage had mote capsules damaged by insect when compared with other treatments. Significantly higher seed yields were obtained from plants sprayed against insects at the flowering stage.