Abstract :
Hypovirulent Gaeumannomyces graminis var, tritici
strain L108hv, five strains of Pseudomonas spp., and a
mixture of four of these bacterial strains were used individually
and in combination for the suppression of takeall
ofwheat. In the growth chamber, L108hv and all five
individual bacterial strains provided a significant
reduction in take-all severity compared with an untreated
control. Combination of L108hv and the bacteria did not
significantly enhance the suppressiveness of either agent.
In the field at Pullman, WA, 108hv significantly reduced
crown root infection of winter wheat but not seminal
root infection, while the reverse was true for a mixture of
bacterial strains suggesting these agents may be more
effective at different stages in disease development. In a
second field trial at Pullman, yield of spring wheat was
increased by 20.8%. In contrast, in two field trials at Mt.
Vernon, WA, L108hv had no effect on take-all of spring
wheat. We conclude that specific biocontrol agents may
be better stiited for certain environments and that biocontrol
treatments should be customized for the target site
