Date of this Version
Chapter in 2012 Crop Production Clinic Proceedings, University of Nebraska-Lincoln Extension, Institute of Agriculture and Natural Resources, pp. 124-127.
The effect of damage caused by blowing soil and leaf contact with high speed winds and hail will all create a similar level of wounding that is often sufficient for pathogens that require wounds to enter (infect) plants. As we look at the level of disease and crop damage we can identify several examples in the corn and soybean disease systems when this can be a factor that could lead to significant disease development and possibly trigger a disease management action.
Hail and wind damage can result in an open canopy which can affect the microclimate and impact disease development. For example, results from research conducted at the University of Illinois demonstrated that simulated hail injury could increase gray leaf spot disease severity in areas of the field where the canopy was more open (Bradley and Ames, 2010). Anyone that has walked a corn field has noticed more disease in open spots in the field and along edges or pivot roads. This increase in disease severity is the result of the canopy changing temperature more rapidly and dew periods being lengthened, thus favoring disease development.
In this research project, although simulated hail injury had a significant effect on plant yield both years, the application of a foliar fungicide (either pyraclostrobin or azoxystrobin) did not improve yield compared to nontreated controls that were also injured.