Sugarbeets (Beta vulgaris L.) grown in the western United States are subject to hailstorms that reduce yield and profits to the grower. A better understanding of growth characteristics before and after hail damage will enable growers to make correct decisions regarding soil and plant treatments to hasten recovery from hail damage and maximize sucrose yields. Most studies of hail damage to sugarbeets, however, have simulated hail defoliation, using various mechanical flails. These have shown

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... the decrease in root and sucrose yields depends on the plant growth stage when plants are injured and the degree of defoliation. Morris (8, 9) 3 found in Montana that 25, 50, and 100% plant defoliation in late June or July reduced sugarbeet yields by < 10, 17 and 25%, respectively. Losses were smaller when sugarbeets were defoliated in late August. Jones, et al. (5) in England found that 50, 75 and 100% plant defoliation at the 4-to 8-leaf stage caused root yields to decrease 5, 10 and 27% respectively. Afanasiev and coworkers (1, 2) in Montana reported that yield reductions were maximum from mid-season defoliations and equaled 5, 9, 10 and 31%, respectively, for 25, 50, 75 and 100% defoliation. Sucrose percentage was decreased very little, except for the 100% defoliated plants. September injuries had little effect on yields. Lilly and Harper (6) in southern Alberta, Canada, reported that root yields were significantly decreased when sugarbeets were defoliated 25% at 60 days, 50% at 45 days or 75% at 45, 60 and 75 days after seeding. Soine (10) in the Red River Valley in Minnesota and North Dakota reported that the greatest reductions in yield occurred from damage on August 15, and these were 7, 13, 14 and 28% for the 25,