The sensitivity of flower bud thrips, Megalurothrips sjostedti Trybom (Thysanoptera: Thripidae), on cowpea to three concentrations and spraying schedules of Piper guineense Schum. & Thonn. extracts

摘要

The extracts of pods of West African black pepper, Piper guineense, at 5, 10 and 20% (w/v), were applied at two, four and six weekly schedules to control the legume flower bud thrips, Megalurothrips sjostedti on flowers of cowpea, Vigna unguiculata. The trials were conducted for 2 years under rain fed conditions in the northern Guinea savanna region of Nigeria. The results showed that the M. sjostedti population was significantly controlled on treated plots compared with the untreated check in both years. The extracts at the 20 and 10% rates and with six or four weekly applications significantly (P < 0.05) reduced thrips pressure on cowpea flowers, were better than the 5% extract at all spraying schedules, and had the same efficacy as the synthetic insecticide treatment. Pod density per plant was significantly higher (P < 0.05) on plots treated with the 20% extract at six or four weekly applications compared to other extract rates and was similar to that of the synthetic insecticide treatment. Thus, the extracts could be a good alternative to the synthetic insecticides on organically managed farms as well as on farms of limited resource farmers in the tropics and subtropics.Keywords:control of Megalurothrips sjostedti; extracts of Piper guineense; Vigna unguiculata; application Scheduledownload PDF Impact factor (Web of Science – Thomson Reuters) 2016: 0.742