Core Ideas Severe early‐season defoliation, such as hail injury, may cause abnormal growth and development of corn tassels. If defoliation induced tassel deformation occurs within a large field, poor pollen production could greatly reduce yield. Certain genetic backgrounds may be more likely to express tassel deformation in response to early‐season defoliation.

Multi‐peril crop insurance (MPCI) requires that if corn ( Zea mays L.) is insured for grain and the producer wants to use it for another purpose, that is, silage, the producer must have the corn grain yield appraised before corn silage harvest. This appraisal requires an adjuster to determine the weight of grain corn, and based on stage of maturity, apply a factor to convert the determined weight to the weight of mature corn at 155 g kg −1 moisture. This study was designed to test the hypothesis that corn grain yield can be estimated accurately before grain is combine harvested using the USDA–Risk Management Agency (RMA) methods and routine silage quality measurements for starch. Corn was established at two locations from 2006 to 2008. Management factors involving planting date, hybrid, and harvest timing were applied to create a range in yield and forage quality. Both RMA methods and the starch‐based method underestimated combine grain yield by 4 to 36% at silage harvest stages between 75 and 25% kernel milk (KM). At silage harvest, the starch method estimated final combine grain yield more accurately than the RMA maturity line weight (MLW) method, but when applied after silage harvest or just before grain harvest, the RMA Weight method was the better predictor of final combine grain yield. With careful assessment, starch‐analysis of silage theoretically could produce an equitable estimate of grain yield for insurance adjustments.

The current standard for assessing corn (Zea mays L.) yield loss due to stand reduction from hail assumes that remaining plants lose the ability to compensate for lost plants by mid-vegetative growth. From 2006 to 2009, experiments were conducted over 12 site-years in Illinois, Iowa, and Ohio to determine the agronomic responses of corn to stand reduction at the 5, 8, 11, and 15 leaf collar stages (V5, V8, V11, and V15, respectively), and whether these responses vary between uniform and random patterns of stand reduction with differences in within-row interplant spacing. When compared to a control of 88,900 plants ha(-1), grain yield decreased linearly as stand reduction increased from 16.7 to 50%, but was not affected by the pattern of stand reduction. This rate of yield loss was greatest when stand reduction occurred at V11 or V15, and least when it occurred at V5. With 50% stand loss, yield was 83 and 69% of the control when stand loss occurred at V5 and V15, respectively. With 16.7% stand loss at V5, V8, or V11, yield averaged 96% of the control. Per-plant grain yield increased when stand loss occurred at earlier stages and was more severe. With 50% stand loss at V11 or V15, per-plant grain yield increased by 37 to 46% compared to the control. These results show that corn retains the ability to compensate for lost plants through the late vegetative stages, indicating that current standards for assessing the effect of stand loss in corn should be re-evaluated.

Soybean [Glycine max (L.) Merr.] producers across the United States are confronted with significant economic losses annually from hail. Plant injury and yield loss are associated with defoliation and node or stand loss due to bruising and breaking of plant stems from the hail. The correlation of yield loss and leaf defoliation is well defined; however, limited information exists relative to whole plant loss. This research was designed to simulate severe hail injury by quantifying the influence of whole plant removal at different development stages on soybean seed yield and composition. Research was conducted near Clay Center, NE and West Lafayette, IN from 2003 to 2005. The timing of removal (V3, V6, R1, and R3.5) and the percent of plants removed (0, 25, 50, and 75%) were simultaneously studied. Seed yield decreased linearly as percent stand reduction increased at each location at all plant removal timings. The severity of yield loss differed within location and was dependent on removal timing and percent stand reduction. Soybean seed mass was nonresponsive to the various treatments except when plants were removed at R3.5. Seed oil content increased when 75% of plants were removed across all removal timings whereas seed protein response to plant removal timings was variable. Our research indicated that hail injury that leads to significant stand loss will cause yield loss as early as V3 soybean. Our data also suggest that stand loss did not have a deleterious effect on percentage oil content.

This is the third year of a multi-year study to determine the effect of simulated hail damage on oil yield of peppermint. Damage levels were 33, 67, and 100 percent inflicted 17 and 35 days before harvest. There was a yield loss for all levels of damage inflicted both 17 and 35 day prior to harvest. The amount of oil per biomass was increased by all treatments 35 days prior to harvest and by 33 percent damage 17 days prior to harvest.

This is the second year of a 3-year study to determine the effect of simulated hail damage on Kentucky bluegrass (Poa pratensis) seed yields. Treatments were applied at three growth stages in the spring to simulate 33, 67, and 100 percent damage. Treatments of 33 and 67 percent damage applied at head emergence caused significantly greater yield reductions than those applied at the boot stage or seed fill. It appears the plant may be particularly sensitive to damage at head emergence. When 100 percent damage was applied at the boot stage, seed yield was reduced by only 59 percent, indicating the plants may be able to recover from significant damage at that stage.