Biocidal activity of selected plant powders against <i>Tribolium castaneum</i> Herbst in stored groundnut (<i>Arachis hypogaea</i> L.)

Abstract

The efficacy of powders of plant parts from Telferia occidentalis (fluted pumpkin), Zingiber officinale (ginger), Vitex grandifolia (Vitex) and Dracaena arborea (dragon tree) at 5g, 10g, and 15g/500g seeds was tested using Completely Randomized Design (CRD) against the storage pest Tribolium castaneum (Herbst) in groundnut in the laboratory. At 28 days after application, mean number of seeds damaged/85 cm³ scoop at the concentration of 5g powder/500g seeds was 2.00 for D. arborea and 3.00 for V. grandifolia and were significantly lower (p ≤ 0.05) than the control (6.67). Phostoxin gave complete control (0.00). Five grammes (5g)/500g of D. arborea and V. grandifolia were as efficacious as phostoxin in protecting groundnut seeds against damage by T. castaneum. No adults were recovered from seeds treated with 10g and 15g of D. arborea at 14 days after application of plant powders. Adult recovery (0.33) from seeds treated with V. grandifolia was equally poor and significantly lower (p ≤ 0.05) than the control (16.33). Larval recovery from seeds treated with V. grandifolia (0.33) and D. arborea (0.67) were significantly lower (p ≤ 0.05) than the control (10.00). At the end of three months of storage, mean weight loss from original weight of 500 g was 81.77g (16.35%) for untreated seeds, 28.58g (5.72%) for V. grandifolia and 28.56g (5.71%) for seeds treated with D. arborea. Phostoxintreated seeds suffered minimal loss (0.76%). D. arborea and V. grandifolia at 5g/500g of seeds are recommended for post-harvest control of T. castaneum in stored groundnut for planting.

Keywords: Plant powders, biocidal activity, Tribolium castaneum, groundnut.