Impact of hail on cereal crops will depend on growth stage of the crop at the time of the hail event and the severity of damage. In the article “Hail Damge in Small Grains” by Joe Lauer, Universityof Wisconsin, it states before jointing, small grains are least susceptible to hail damage. The spike is still below ground and protected from injury.
In a study by R.H. Busch in North Dakota in wheat, the greatest yield reduction resulted when stems were broken in the milk stage, followed by anthesis, soft dough, boot, and hard dough stages – see Table below (Busch, 1975).
|Grain yield reduction in spring wheat with 100 percent of stems bent.|
|Growth stage||Yield reduction (%)|
|Boot (Zadoks 45)||28 to 39%|
|Anthesis (Zadoks 65)||15 to 60%|
|Milk (Zadoks 75)||30 to 70%|
|Soft dough (Zadoks 83)||16 to 55%|
|Hard dough (Zadoks 87)||3 to 47%|
|Table derived from Busch, 1975|
Source: Busch, R. H. 1975. The effect of simulated hail injury on spring wheat. North Dakota AES Bulletin 497. 18 pp.
Remember that estimating yield loss due to hail is only an estimate. The remainder of the growing season will help determine final yields. Please contact your hail insurance provider for their procedures in assessing hail damage as they may be different than what has been provided here.
Submitted by: Pam de Rocquigny, MAFRI Cereal Crops Specialist