THE INCIDENCE AND SPATIAL PATTERNS OF WHEAT PLANTS INFECTED BY FUSARIUM-GRAMINEARUM GROUP-1 AND THE EFFECT OF CROWN ROT ON YIELD

The incidence and spatial patterns of wheat plants infected by Fusarium graminearum Group 1 were assessed in six fields in northern New South Wales, Australia, over a four-year period. The incidence of infected plants declined from 1978 to 1981 in fields where wheat was sown each year, where there was a bare fallow of 18 months and where sunflowers were sown in one season. The pattern of infected plants tended to be regular (uniform) where the incidence of infected plants was particularly high (> 96%). In all fields where a clustered (aggregated) pattern was detected, 12% to 64.4% of plants were infected. A random pattern was observed at a number of sites. There was a positive association between loss in potential yield and the incidence of infection, basal browning of plants and whiteheads. Losses of up to 89% were recorded.