Perceived Ineffectiveness of Insecticides Used to Control Cotton Pests in the Western Cotton Growing Areas of Tanzania

Abstract

The ineffectiveness of insecticides against cotton pests has been a haunting scourge to cotton farmer, for almost a decade. Cotton farmers blame Tanzania Cotton Board (TCB) while the later blames the Tropical Pesticides Research Institute (TPRI) for registering and allowing the unrestricted sale of ineffective and counterfeit products. Lack of correct information about proper use of insecticides brought about the knowledge gaps that had to be fixed. Survey on the source, acquisition, storage and use of insecticides supplied by Tanzania Cotton Development Trust fund (CDTF) and agro dealers was conducted in some selected Districts (Meatu, Maswa, Bariadi, Kwimba and Misungwi) of Western Cotton Growing Areas (WCGA) of Tanzania followed by two-years field experiments at Tanzania Agriculture Research Institute (Ukiriguru centre) to determine the efficacy of five insecticides commonly used by farmers. Zetabestox (Zeta-Cypermethrin 5% E.C), Duduall (Cypermethrin 150 g/L + Chlorpyrifos 300 g/L E.C), Ninja (Lambdacyhalothrin 50 g/L E.C), Bamethrin (Deltamethrin 2.5% E.C) and Agromethrin (Alfa-Cypermethrin 5% E.C) against key insects pest of cotton in Tanzania. The results showed that, most of the insecticides supplied to cotton farmers of selected Districts of WCGA were acquired from CDTF yet some cotton farmers acquire insecticides from agro shops within their proximities. The results also showed that all insecticides were statistically equally effective against major cotton insects pest when sprayed at 20% and 30% threshold during the first, second, third and fourth round compared to unsprayed check of the experiment for both two years 2015/2016 and 2016/2017. The unsprayed check had more insect pests, more damaged buds, leaves and bolls than all other treatments at P<0.05.