Comparative effect of two indigenous organic biopesticides and Furadan 3g in the management of Meloidogyne incognita in soybean (Glycine max (l.) Merrill

Abstract

The soybean crop improvement programme in Nigeria led to the development of several high-yielding varieties. However, TGx 1019-2EN which is one of the top-yielding varieties has been devasted by Meloidogyne incognita, the most predominant phytonematodes attacking crops worldwide, including Nigeria. Due to the increasing health hazards associated with the use of some synthetic nematicides globally, scientists have continued to explore several non-chemicals, especially biopestides as safer and cheaper nematode disease management alternatives, especially in organic agriculture production system. Therefore, leaf powder of organically grown Azadirachta indica, and Carica papaya, were evaluated alongside a commonly-known synthetic pesticide, Furadan 3G, singly or in combination with each other, for their effectiveness in the management of the southern Root-knot nematode disease in susceptible TGx 1019-2EN soybean variety, a very important oilseed crop. The relative efficacy of the two leaf powders and the Furadan 3G in the reduction of Meloidogyne spp. population and soybean growth were determined. The leaf powders were prepared using leaves of A. indica (Neem leaf) and C. papaya (Pawpaw leaf) and used in amending sterilized soils potted and grown to TGx 1019-2EN, and two weeks seedlings inoculated with the nematode eggs. The experiment was laid out in a Completely Randomized Design with four replications. Powder of Azadirachta indica was most effective (P ≤ 0) in reducing nematode population in the soil. Both neem leaf powder (NLP) and its counterpart pawpaw leaf powder (PLP) treatments produced taller soybean plants (57.38 – 58.40 cm, 84.50 – 85.98 cm and 89.20 – 88.38 cm at 2WAI, 4WAI, and 8WAI, when compared with the control (P ≤ 0). Soybean root gall index significantly (P ≤ 0) reduced from 15.75 in the control pots to 2.00 in NLP-treated plots, representing 87.30%.