Biological control of common root rot of spring wheat by coating seeds with Bacillus or Trichoderma spp.

الملخص EN

Common root rot of wheat (Triticum aestivum L.) caused by Fusarium graminearum and Cochliobolus sativus is the most destructive disease in Qassim region, Saudi Arabian fields.

The objective of this work was to obtain and test new bioagents for control of wheat root rot.

Rhizobacteria isolated from healthy wheat roots were tested for their antagonistic effect on F.

graminearum and C.

sativus in petri plates.

Bacillus polymyxa and a new Bacillus sp.

were selected for their strong antagonists to F.

graminearum and C.

sativus.

Bacillus isolates and two Trichoderma spp.

were applied to wheat seeds and sown in soil infested with F.

graminearum and C.

sativus and tested in both greenhouse and field experiments for two successive growing seasons (1998 / 1999 and 1999 / 2000).

Application of rhizobacteria to wheat grains reduced incidence of seedlings foot rot in greenhouse experiments.

Meanwhile, seed treatment with Bacillus spp.

reduced severity of common root rot symptoms significantly and increased wheat grain yield up to 102 % compared to Vitavax treated seeds in the field.

Wheat seeds treated with Trichoderma spp.

improved plant growth and increased wheat grain yield in the field up to 62%.

The efficacy of the tested biocontrol agents was greatly affected by growing season.