Biopesticides as Eco-friendly Alternatives for the Management of Root-Knot Nematode, Meloidogyne incognita on Cowpea(Vigna unguiculata L.)

Biopesticides based on pathogenic microorganisms or plant origin offer an ecologically sound and effective strategy for the management of plant parasitic nematodes. Therefore, a greenhouse experiment was conducted to assess the impact of six commercial biopesticides on root knot nematode, Meloidogyne incognita infecting cowpea. Biopesticides used in the present study were: BioArc® (Bacillus megaterium), BioZeid® (Trichoderm album), BioNematon® (Paecilomyces lilacinus), NemaStop (5% CS Abamectin, Streptomyces avermitilis), and Tervigo (2% avermectin, S. avermitilis) and Neem Azal-T (Azadirachtin) compared to chemical nematicide, oxamyl and untreated check. All biopesticides were applied as soil drench one (3days) and two times (3 and 10 days) after nematode inoculation at their recommended rates. Both times of application achieved a significant (P≤ 0.05) improvement in plant growth parameters and significant suppression in nematode population. In most treatments, application of biopesticides two times was better than those applied once. BioArc® applied two times recorded maximum augmentation in shoot length and plant biomass. Whilst, BioNematon recorded the highest percentages of reduction in total nematode population, number of females, egg masses and eggs/single egg mass. All the tested biopesticides significantly showed positive percentages of increased values in biochemical constitutions i.e. nitrogen (N), phosphorus (P) and potassium (K), photosynthetic pigments (Total chlorophyll content and Carotenoids), and plant defense substances (Ascorbic acid, Salicylic acid and Total phenol content).