Integration of Biological and Fungicidal Alternatives for Controlling Foliar Diseases of Vegetables Under Greenhouse Conditions

Abstract

Evaluation the efficacy of bio-agents, resistance chemical inducers and/or thyme oil application as foliar spray against vegetables foliar diseases incidence was carried out in open greenhouse conditions. The tested bio-agents were Trichoderma harzianum, T. Viride, Bacillus subtilis, Pseudomonas flourescens and Saccharomyces serevisiae. Calcium chloride, Potassium monohydrogen phosphate, Potassium bicarbonate, Saccharin, Ascorbic acid, Chitosan and Humic & Folic acid (mixture) as resistance chemical inducers were evaluated. The recorded foliar diseases, i.e. Powdery, Downy mildews of Cucumber, Cantaloupe and Pepper as well as Early, Late blights of Tomato were significantly reduced at all treatments either alone or in combinations comparing with untreated plants. Application with either T. harzianum and B. subtilis showed significant reduction in diseases incidence comparing with the other applied bio-agents. Under artificial infestation the most significant reduction in diseases incidence of tested vegetables were recorded in combined treatments of chemical inducers and S. serevisiae, i.e. (Chitosan + Thyme oil); (Chitosan + Saccharin); (Chitosan + Calcium chloride + S. serevisiae); (Chitosan + Potassium monohydrogen phosphate); (Saccharin + Potassium monohydrogen phosphate) ; (Humic & folic + Thyme oil) and (Chitosan + S. serevisiae) comparing with other applied treatments as well as untreated control. On the light of the present study it could be suggested that the usage of combined application of the bio-agents with resistance plant chemicals might be used as easily applied, safely and cost effective control methods against such foliar plant diseases.