Evaluating potato yield loss following plant injury

Abstract

This information has been developed to make available to the crop insurance adjuster, information previously contained in comprehensive reports as well as information developed especially for this publication. Determining stage of growth and percent plant damage at time of injury are necessary to accurately predict yield loss. Knowledge of the potato plant and its ability to recover following injury may also aid the adjuster in his evaluation. Types of injury following hail damage include defoliation, severed stems and bruised and broken stems. Experiments were conducted which showed that yield losses were usually less than visual estimates of vine damage would indicate. Conclusions drawn from the research include: multiple bruising was not more damaging than one bruise 3/4 of the distance below the plant top and was also similar to 50% defoliation and severing stems 50% through; simultaneous bruising and defoliation did not always have an additive effect over either injury separately; the potato stem possesses an interconnected vascular system so if damage occurs it is likely that one or more vessels will remain functional; severe defoliation results in at least a temporary increase in the photosynthetic rate of remaining leaves. Procedures for the adjuster to follow in the field have been designed to improve the estimate, incorporating the results of the research work. Symptoms of possible injuries present with hail are also included.