Effectiveness of Some Organic Fertilizers and Bio-Control Agents for Controlling Root-Knot Nematodes Meloidogyne spp. in Cowpea Forage (Vigna unguiculata) in New Valley, Egypt

The effect of some organic fertilizers viz., Farmyard manure, chicken manure, date palm compost, filter cake mud and the two bio-control agents Trichoderma viride and Bacillus megaterium alone and/or in a combination against root-knot nematodes Meloidogyne spp., infecting cowpea forage plants under field conditions was studied. The combined treatments showed more efficacy for controlling Meloidogyne spp., reproduction than individual treatments; the most effective treatment in reducing root galling was the combined treatments between B. megaterium or T. viride with date palm compost, followed by the combined treatment of T. viride with filter cake mud. While, the greatest decrease of the numbers egg-masses per root system, and number of eggs per egg-mass were detected by the combined treatment B. megaterium with date palm compost. However, the highest reduction in second stage juvenile j2 in the soil was the combined B. megaterium with chicken manure. The tested treatments increased growth parameters significantly in growing two seasons compared with control treatment. The greatest of plant height, number of branches per plant, and fresh weight were recorded by the combined treatment B. megaterium with chicken manure. The combined treatments increased the content of cowpea forage from minerals viz., nitrogen, phosphorus, potassium, and protein. The highest of nitrogen and protein content of cowpea forage was recorded with the combined treatment B. megaterium with filter cake mud. As well as, the combined treatment B. megaterium with chicken manure recorded the highest contents of potassium and phosphorus in forage cowpea. The second part of this study studied the effect of the above mentioned treatments on the defense-related enzymes and total phenol contents in cowpea forage plants infected with, M. incognita under greenhouse conditions. The combination between organic fertilizers and bio-agents increased activities of defense-related enzyme peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), pathogenesis related protein (chitinase and β1,3 gluconase) and total phenol contents more than applied individually.