Grasshopper injury in relation to stem rust in spring wheat varieties
1939
Smith, R.W.
The leading cereal crops at Dickinson, N. Dak., in the extent of grasshopper injury, ranked in descending order as follows: Barley, oats, wheat, corn, and sorghum. Certain spring wheat varieties were injured by the grasshoppers more than others. With some exceptions, badly rusted wheat varieties were injured considerably more than those showing but little rust. In three different groups of spring wheat in the nursery the correlation coefficients between percentage of stem rust and percentage of grasshopper injury were r = +0.512 +/- .033, +0.767 +/- .028, and +0.787 +/- .016. Several unconfirmed reasons are suggested for the greater damage to rusted varieties. The stage of maturity of a variety seems important but apparently cannot account for all the differences since both early and late varieties were found in both the badly injured and slightly injured groups.
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