Bulletin of the National Research Centre (Apr 2019)

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

  • Hassan Abd-El-Khair,
  • Wafaa M. A. El-Nagdi,
  • Mahmoud M. A. Youssef,
  • Mahfouz M. M. Abd-Elgawad,
  • Mona G. Dawood

DOI
https://doi.org/10.1186/s42269-019-0108-8
Journal volume & issue
Vol. 43, no. 1
pp. 1 – 7

Abstract

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Abstract Background Due to the fact that chemical nematicides frequently cause environmental pollution and toxic hazards to human, plants, and domestic animals, certain biocontrol agents of environmentally and toxicologically safe properties and secure to human and animals were tested against root-knot nematode Meloidogyne incognita on cowpea. Objective The protective effect of two isolates of Bacillus subtilis, B. pumilus, or Pseudomonas fluorescens on M. incognita reproductive parameters infecting cowpea was examined, and consequently, plant growth and yield parameters were investigated. The nematicide, Furadan (10% G) was, also, included in this study for comparison. Results 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). Conclusions The tested biocontrol agents could achieve various degrees of M. incognita control on cowpea under screen house conditions with consequent increase in cowpea growth and yield parameters. These bacterial isolates need to be studied under different field conditions for confirmation.

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