Survival and multiplication of Gaeumannomyces graminis var. tritici (the wheat take-all fungus) and related fungi on different wild and cultivated grasses

Effects of different cultivated or weed grasses, grown as pure stands or in combination with wheat, on take‐all and its suppression in subsequent wheat crops

“…The perennial, cultivated grasses were also less effective hosts, having effects ranging from those of black‐grass to those of fallow. These observations agree with comparisons made among different grasses and wheat in pots (Gutteridge et al ., 2005). Where perennial grasses were grown mixed with wheat in field plots, soil infectivity in May was often less than that in plots with grass‐free wheat.…”

“…The annual brome‐grass weeds, A. sterilis and B. secalinus , were comparable with winter wheat in their ability to maintain take‐all inoculum, at least in July. In recent experiments, A. sterilis was shown to be particularly susceptible to take‐all in comparison with a range of other grass weeds (Gutteridge et al ., 2005), and may therefore sometimes have an important role in maintaining inoculum between wheat crops. Black‐grass ( A. myosuroides ) was a less effective host.…”

“…Most research on grasses as hosts of Ggt has not considered their subsequent effects on epidemic development in wheat, although the effects of the perennial weed grass couch ( Elytrigia repens ) in transmitting take‐all through break crops are well known (Nilsson & Smith, 1981). Some evidence for other grasses was obtained from pot experiments in which wheat was grown after perennial cultivated grasses (Garrett, 1941) and after these or annual weed grasses (Gutteridge et al ., 2005). The latter publication presented evidence to suggest that, in general, annual weed grasses were more effective hosts of Ggt than were cultivated perennial species, allowing its better survival in the absence of wheat.…”

The potential of non‐pathogenic Gaeumannomyces spp., occurring naturally or introduced into wheat crops or preceding crops, for controlling take‐all in wheat

“…This creates opportunities for new approaches to disease management that could involve more flexible use of non‐cropped breaks such as set‐aside (while respecting any regulations relating to the permitted methods and timing of their cultivation). Different grass species sown to provide covers on land in set‐aside may have different effects on take‐all inoculum or suppressiveness to take‐all, with implications for disease in wheat grown subsequently (Bateman et al , 2005; Gutteridge et al , 2005; Gutteridge et al , 2006). They may also provide an opportunity to introduce and multiply known antagonists of take‐all such as the non‐take‐all Gaeumannomyces species and varieties.…”

“…They may also provide an opportunity to introduce and multiply known antagonists of take‐all such as the non‐take‐all Gaeumannomyces species and varieties. These developments in arable farming, as well as recent new findings from infection studies on pot‐grown wheat (Gutteridge et al , 2005), have prompted a re‐examination of earlier, unpublished results on the behaviour of these fungi, either introduced or as natural populations, in crop sequences, and also the establishment of new field experiments to complement the earlier work. Results of all these studies are described here, with the objective of assessing whether practical biological control of take‐all in wheat is possible using fungal antagonists of the disease, either by introducing inoculum into preceding covers or crops or into the wheat crops themselves, or by manipulating natural populations.…”