The root-knot nematode Meloidogyne incognita is one of the most important nematode pests that causes great losses and affects agricultural production, especially on tomatoes. with one or more types of this pest; and the lack of resistance in most plants against nematodes, and the pollution caused by nematicidal pesticides to the environment and a threat to human and animal health, hence the idea of research using materials that are safe for humans, animals and plants and effective in eliminating nematodes intrusive on plants. Several experiments were conducted at the research station of the Faculty of Agriculture in Shebin El-Kom, El-Menoufia Governorate, to study the effect of some biological microorganisms and biological substances in combating root knot nematodes that infect tomato plants and their relationship to some vegetative characteristics of plants. Therefore, the following materials were applied singly and in combinations in four successive experiments:
Glomus mosseae - Trichoderma harzianum - Azotobacter chroococcum - Pseudomonas fluorescens - Steinernema feltiae – Diplogaster lheritieri
From the obtained results, it can be recommended to use the combined treatment of D. lheritieri + A. chroococcum + G. mosseae, which achieved the highest reduction percentages of nematodes more than the percentage achieved by the Oxamyl pesticide , and it also led to an increase in the vegetative and root system, which is reflected on the fruit yield of tomato plants.