Crop & Pest Report


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Hail Damage in Beans and Sunflower (07/12/18)

Every growing season usually has several severe thunderstorms, which sometimes result in crop damaging hail.

Hail Damage in Beans and Sunflower

Soybean and Dry Bean

Every growing season usually has several severe thunderstorms, which sometimes result in crop damaging hail. The growing point of the soybean and dry bean plants is located at the top of the plant where new leaves are emerging. There are also vegetative buds in leaf axils that can serve as growing points where new branches can develop. If the top of the plant is damaged or the stem is cut off above the cotyledonary node, the plant will re-grow from one or more of the axillary buds. However, it will take some time for the plant to recover when many leaves are removed or damaged by the hailstones. Bruised or broken stems are regularly observed after hail, but the hail damage is often not severe enough to kill the plant. Damaged stems may lodge later in the season, especially after pod development and filling. Lodging and plant breaking from hail injury will depend on the severity of the bruising, position of the damage on the stem, the variety, and other environmental factors. Bruised areas of the plant may also be entry points for bacteria or other disease organisms. Loss of leaves opens the canopy which may result in a flush of weeds due to the extra light available for the weeds to germinate and develop. The degree of defoliation and stage of plant development at the time of the hail may affect the expected grain yield. Typically, damage done later in the reproductive phase of the plant will lead to greater percent yield loss. This is a function of limited remaining time until fall plant senescence. Nevertheless, if there are still enough evenly distributed plants remaining, the crop can still produce reasonable yields with a favorable remaining growing season.


The tolerance of the sunflower plant to hail depends on the intensity of the storm, hail size, and the stage of the growth. Sunflower is less tolerant to hail during the budding stage compared to the vegetative stage. Damage occurs from defoliation and severely bruised or broken stems (Photo 1). If the growing point is hit by hail and removed, sunflower plants may branch out and result in many small heads. Those tiny heads will not contribute to yield.



Hans Kandel

Extension Agronomist Broadleaf Crops

This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

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