Protective effect of Bacillus subtilis, B. pumilus, and Pseudomonas fluorescens isolates against root knot nematode Meloidogyne incognita on cowpea

Abstract

Bacillus subtilis (Bs2) recorded the highest average total percentage reduction (82%) of M. incognita reproductive parameters followed by B. pumilus Bp2 (81.8%). Also, Carbofuran 10% recorded the highest average total percentage reduction (76.5%) in terms of numbers of second-stage juveniles (J2) in plant roots and soil as well as nematode galls and eggmasses compared to the untreated check. The highest total average percentage plant growth increase (99%) was obtained by B. pumilus (Bp1), but B. subtilis (Bs2) and medium recorded 26.3 and 12.8% only, respectively. P. fluorescens (Pf1) scored the highest yield increase (97%) followed by Pf2 (63.8%). Number of bacterial nodules showed the highest percentage increase (78%) by P. fluorescens (Pf2). B. pumilus (Bp1) caused the highest increase of phenolic compound contents followed by P. fluorescens (Pf1). The nematicide Carbofuran 10% G was the first in increasing soluble protein contents followed by P. fluorescens (Pf1). Bacillus pumilus (Bp1) caused the highest total contents of photosynthetic pigments followed by P. fluorescens (Pf1) and (Pf2).