Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Plant Science

First Advisor

George W . Buchenau


This paper deals with the assessment of yield loss due to wheat scab. The following paragraphs discuss the topic of why loss estimates are needed, why they are difficult to obtain, and how the research provides information toward these ends. Reasonably accurate loss estimates are needed for two purposes: one of the most important may be to guide further research on the problem. In addition, methods of loss assessment are needed to evaluate the degree of control provided by fungicides, cultural practices, or resistant cultivars. Loss estimates are difficult to obtain for two reasons. First, the time period during which the symptoms are visible is very short; the observer has perhaps ten days to survey the research experiment, production field, county, state or region. This time frame also coincides with the time that other research and extension activities are creating maximum demands on the wheat worker's time. Therefore, the need exists for survey methods that are simple, fast, and reasonably accurate. A second obstacle to estimating scab losses is the uncertain relationship between disease severity, maturity level of the crop, cultivar resistance, and yield loss. These interrelationships are the subject of the research presented here. Specifically, the objectives of the research were: 1. To develop simple regression models for the relationship between yield loss of spring wheat (y) and scab intensity (x) at various times after anthesis. 2. To determine if the regression coefficients obtained are similar for all cultivars. 3. To determine if these relationships are independent of the rate of disease progress.

Library of Congress Subject Headings

Wheat -- Diseases and pests
Wheat -- Losses



Number of Pages



South Dakota State University


No Copyright - United State