Efficacy of Different Rates Of Formulated Neem Seed Oil And Frequency Of Application On The Control Of Flower Thrips Infesting Early Maturing Pigeonpea Cultivar In Owerri, Imo State, Nigeria.

Thrip (Megalurothrips usitatus Bagnall) poses a serious threat to pigeonpea production in Nigeria. Studies on the thrips population management using formulated neem seed oil (F-NSO) at different doses and spraying frequencies was examined. The study was carried out in the Postgraduate Teaching and Research Farm, Department of Crop Science and Technology, Federal University of Technology, Owerri (FUTO) Imo State, beginning from May 2009, 2010 and July 2010. The experiment was laid out in 3 x 5 factorial comprising three rates of F-NSO, 2 ml (4.2 L ha-1), 4 ml (8.3 L ha-1), 6 ml (12.5 L ha-1) with 0 ml (0 L ha-1), and synthetic pyrethroid (cypermethrin) 0.72 ml (1.5 L ha-1) as check plots and three intervals of application: once a week, once in two weeks, and once in three weeks. Results showed that the application of synthetic pyrethroid (SPY) significantly (p<0.05) controlled the population of M. usitatus while formulated neem seed (F-NSO) control measures showed non-significant (p<0.05) effect on the population of M. usitatus even at higher dosage of 6 ml (12.5 L ha-1) at once a week 2 or 3 weeks in a four spraying regime. The different rates of F-NSO were not effective in controlling the population of the flower thrips while SPY showed effective control but lacks merit due to its toxic in nature. More research efforts are going on in the Department of Crop Science and Technology (FUTO), towards mixing F-NSO with two or more plant extracts that might have very strong systemic activity which can penetrate flowers to cause mortality of the thrips. Keywords: Improved pigeonpea, Thrips, flowers, population, formulated neem seed oil, rates, and frequencies