Hadeel Badri Dawood - Department of Plant Protection, Agricultural Engineering Sciences Collage, University of Baghdad, Iraq
Saad Tareq Abdul Malek Yass - Department of Plant Protection, Agricultural Engineering Sciences Collage, University of Baghdad, Iraq

This study was conducted to isolate biological control agents from soil samples surrounding the roots of uninfected cucumber, watermelon, eggplant, tomato, and okra plants in fields infested with root-knot nematodes and to evaluate their effectiveness. Therefore, fifteen bacterial isolates were selected to study their effects on the vitality of the second stage juveniles (J۲) of the root-knot nematode, Meloidogyne incognita. Nine bacterial isolates showed a mortality rate of juveniles ranged between ۸۰ and ۱۰۰%, while isolate HB۸ was unique in having a high ability to influence the vitality of the juveniles, as the mortality rate reached ۱۰۰%. This isolate was chosen to test its effectiveness in inhibiting egg hatching. The results showed that the inhibition rate after ۷۲ h of incubation reached ۹۴.۳۳%. The effect of the bacterial filtrate of isolate Priestia megaterium HB۸ was tested using three concentrations (۱۰, ۲۰, and ۳۰%) on the mortality rate of J۲ and the inhibition rate of egg hatching. Moreover, the ۳۰% concentration exhibited a high ability to increase the mortality rate of a juvenile to ۹۷.۶۶% after ۴۸ h of incubation, while the inhibition rate of egg hatching was ۹۶.۶۶% after ۷۲ h.

Priestia megaterium, Root-knot nematode, Meloidogyne incognita