Effect of Certain Pseudomonas fluorescens Isolates on Root-Knot Nematode, Meloidogyne incognita on Eggplant as Affected by the Time of Addition

Abstract

Under screen house conditions, four isolates of bacterium, Pseudomonas fluorescens (Pf¹, Pf², Pf⁹ and Pf¹⁰) were used for controlling of root-knot nematode, Meloidogyne incognita (Ne) on eggplant as influenced by time of addition. The obtained results proved that, the tested isolates adversely affected reproduction of root-knot nematode, M. incognita, either when bacterium was added before, after or at the same time with Ne inoculation. On the basis of the average overall percentages nematode reduction, bacterial isolates added before and after nematode inoculation were equal in decreasing M. incognita numbers, as they achieved higher average overall reduction (69.8%), when Pf isolates were added with the same time with Ne. Also, number of galls recorded the highest overall percentage reduction (60.3%), when Pf isolates were added before Ne followed by other groups. Also plant growth criteria improved according to the tested material at the time of addition and the highest percentage plant growth increase (55.5%) was achieved, when Pf isolates were added before Ne. As for enzyme activity, peroxidase and polyphenol oxidase activities increased at the different degrees as influenced by the different treatments. When comparing on the basis of average percentages potential of peroxidase activity, the highest potential (2.446%) was recorded, when P. fluorescens was added, 3 days after nematode inoculation than the other treatments. Bacterium and nematode applied at the same time were the first in increasing polyphenol activity (3.907%) than the other groups, but there were no significant differences among them.