A model simulating grasshopper damage to wheat planted in infested stubble.
The authors present a model simulating the effects of the acridid Melanoplus sanguinipes on the yield of spring wheat planted in infested stubble. The data suggested that the model tended to overpredict yields in favourable situations (adequate rainfall, no M. sanguinipes attack), and to underpredict in unfavourable conditions. Tentative economic injury levels developed from the model suggest that economic thresholds for wheat planted in infested stubble should be lower than the general threshold now in use in western Canada. The danger of economic damage would be particularly acute, according to the model, if wheat were planted late in a warm, dry season or if M. sanguinipes were to hatch early relative to planting date.