الفهرس 
Title : Potency evaluation of some microorganisms against root-knot nematodes in tomato plant /
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Abstract
Root-knot nematodes are the major limiting factor in tomato production in many regions of the world including Egypt. These nematodes disrupt the physiology of the plant and reduce crop yield and product quality. Alternative methods are required for control of nematodes because of high toxicity of current chemical pesticides. Therefore, the present study aimed to evaluate the biocontrol activity of some microorganisms against root-knot nematodes under both in vitro and in vivo conditions. Sixteen Trichoderma isolates were assayed for chitinase activity using basal solid medium supplemented with colloidal chitin and bromocresol purple. Four Trichoderma isolates recorded the highest chitinase activity, were identified morphologically as Trichoderma asperelloides, T. hamatum, T. harzianum and T. viride. Further, five bacterial isolates viz., three Serratia isolates, Bacillus subtilis isolate and B, megaterium isolate were primary screened for their chitinase potentiality by using chitin agar medium. All tested bacterial isolates showed chitinolytic activity except for B. subtilis. Moreover, the four selected Trichoderma species and the chitinolytic bacterial isolates were quantitatively assayed for their chitinase activity. Maximum chitinase activity (1.736 U/mL) and specific activity (0.176 U/mg) were recorded in case of T. asperelloides. In vitro studies revealed that egg hatching and second stage juveniles vitality of Meloidogyne incognita were inhibited by chitinase-containing growth culture suspensions as well as free cells culture filtrates of all tested microbial isolates but at different rates