Impact of rates and frequency of formulated Neem Seed Oil (F-NSO) on pest damage of improved Pigeonpea cultivar in Southeastern Nigeria

Abstract

Research on Podsucking Bugs (Riptortus dentipes Fab., Hemiptera: Coreidae) was carried out at the Postgraduate Teaching and Research Farm, Department of Crop Science and Technology, Federal University of Technology, Owerri Imo State beginning from MAY 2009, MAY 2010 and JULY 2010. In this study, the populations of the R.dentipes and pod/seed damages were monitored under control with formulated Neem Seed Oil (F-NSO) and Synthetic Pyrethroid (SPY) (cypermethrin) at different rates and frequencies. July planting season often chosen by farmers as the appropriate planting date was also subjected to control strategy with F-NSO to determine plant performance under pest control measures. The experiment was laid out in 3 x 5 factorial comprising three rates of F-NSO: 2 ml (4.2L ha-1), 4 ml (8.3L ha-1), 6 ml (12.5L ha-1) with untreated control (OL ha4), and SPY 0.72 ml (1.5L ha-1) as checks. There were three intervals of application: once a week, once in two weeks, and once in three weeks. Results from the research showed that application of F-NSO at the highest dose of 12.5L ha4 and at four regime spraying intervals of once a week significantly (p<0.05) reduced the population of R. dentipes on pigeonpea plants resulting to reduced pod/seed damage and better pod/seed quality observed irrespective of the planting seasons. In the humid environment of Owerri in South eastern Nigeria, application of 6 ml (12.5 L ha-1) of F-NSO once a week and at four spraying intervals especially during July pigeonpea planting season should be incorporated into pigeonpea Integrated Pest Management Programmes (IPM) as the planting season witnessed low pod/seed damage with enhanced seed quality (percentage wholesome seeds) when compared with MAY planting season.