Barley (Hordeum vulgare �Conlon, Drummond, Lacey, Legacy, Robust�)�������������������������� S. Halley
���� Fusarium head blight; Fusarium graminearum����������������������������������������������������������������
���� Septoria leaf blotch; Septoria passerinii���������������������������������������������������������������������������
Barley cultivar response to fungicide application for the control of Fusarium head blight and leaf disease, 2003.
The experiment was conducted
Stand reduction was evident early in the growing season, Table 1. Visual assessment of the roots indicated infection from Pythium sp. An assessment of the % ground coverage of each plot was made at Feekes growth stage 6 and recorded as percent reduction to reflect differences due to Pythium sp. Conlon had significantly greater ground coverage than other cultivars and Drummond had significantly less coverage. Leaf disease developed at a late growth stage and was visually assessed on 1 Aug by evaluating 5 leaves/plot. Conlon had the greatest leaf disease levels. Leaf disease on Drummond and Legacy was less than Lacey. Fusarium head blight levels were low and all fungicides reduced levels to less than 1%. Mean Fusarium head blight (FHB) incidence and severity (spikelet count per individual head multiplied times incidence of FHB infected spikes per plot) by untreated cultivar were 41 and 1.9, 55 and 2.6, 60 and 3.8, 58 and 2.2, and 53 and 2.4 for Conlon, Drummond, Lacey, Legacy, and Robust, respectively. Despite early season growth problems the growing season was one of the most productive in recent years due to little visible disease development. All yields were excellent. Lacey and Legacy had greater yields than the other cultivars. Test weight was not affected by fungicide application to Conlon and Legacy, increased by treatment that included subsequent application of JAU 6476 to Drummond, increased treatment that included a subsequent Folicur application to Lacey, and reduced by treatment with subsequent Folicur application to Legacy Figure 1. Test weight increases and decreases did not appear to be correlated with leaf disease. Plumps were excellent in all treatments. Treatments that included JAU 6476 had greater plumps. Conlon has been reported to have less deoxynivalenol concentration than many cultivars. Similar results were detected in this trial, Figure 2, with slight differences between some other cultivars. Subsequent applications with JAU 6476 reduced deoxynivalenol levels over Folicur applied alone on Legacy cultivar. Treatments than included either subsequent fungicide application reduced deoxynivalenol levels on Lacey. Deoxynivalenol reductions were measured by all fungicide applications to Drummond, Lacey, Legacy, and Robust.
Table 1. Pythium, leaf disease, yield, test weight, plump, and DON by cultivar and fungicide, 2003.
Figure 1. Test weight by barley cultivar and treatment, Langdon 2003.
Figure 2. Deoxynivalenol levels by barley cultivar and treatment Langdon, 2003.