Efficacy of Syringa (Melia Azedarach L.) extracts on eggs, nymphs and adult red spider mites, Tetranychus spp. (Acari: Tetranychidae) on tomatoes

Abstract

This study evaluated the effect of Syringa (Melia azedarach) fruit and seed extracts (SSE) on red spider mite (Tetranychus spp.) eggs, nymphs and adults. Bioassay investigations were carried at the Vegetable and Ornamental Plant Institute (VOPI) outside Pretoria in South Africa using different concentrations (0.1, 1, 10, 20, 50, 75 and 100%) of SSE. Mortalities were measured at 24, 48 and 72 h after treatment and compared to the effects of the synthetic acaricides: Abamectin, chlorfenapyr and protenofos. A completely randomized design (CRD) was used with 12 treatments. Analysis of variance (ANOVA) was used to test for effects of treatments. Differences in treatment means were identified using Fisher’s protected t-test least significant difference (LSD) at the 1% level of significance. Data were analysed using the statistical program GenStat (2003). The result of the analyses revealed that the efficacy of SSE and commercial synthetic acaricides increased with exposure time.Concentration of 50% and above SSE was as effective against red spider mite (RSM) adults, eggs and nymphs as the synthetic acaricides. Key words: Syringa fruit and seed extracts, Melia azedarach, red spider mites, acaricidal activity, tomatoes.