Effect of some Kinds of Fungal and Bacterial Biopesticides for the Control of Damping-off and Root Rot Fungi of Okra Seedlings in the Greenhouse

Abstract

Fungal biopesticides preparations Trichoderma harzianum, T.viride individually or in combination with the bacterial biopesticides Pseudomonas fluorescens or Bacillus subtilis showed a significant inhibition to the mycelial growth of fungi causing damping-off and root-rot of okra seedlings Abelmoschus esculentus L.. The maximum inhibition of the growth of fungal colonies was recorded with a mixture of Trichoderma harzianum + Pseudomonas fluorescens which caused complete inhibition (100%). Seed treatment with a mixture of biopesticides proved to be superior than individual treatments in reducing the infection of damping –off disease significantly and increasing the length of shoots and roots and dry weight of the plant. The use of biofungicide preparations individually or in mixture raised the levels of peroxidase and polyphenol oxidase enzymes indicating the induction of systemic resistance of okra plants against fungi causing damping- off and root-rot disease. A highest enzyme activity was noticed with Trichoderma harzianum + Psedomonas fluorescens in soil contaminated with F.solani or M. phaseolina and reached 2.823 and 0.185/min./g fresh weight respectively.