This year white mold was prevalent in Iowa, causing more severe damage than in 1992 and 1994. The disease is going to stay, and is very likely to increase in future if we do not manage it properly. I have developed two new sources of information that may help soybean producers manage this disease:

• an information sheet that lists results of the 1996 variety tests for tolerance to white mold
• a white mold educational slide set.

Information sheet on variety tests

This year, we tested 63 entries of soybeans for tolerance to soybean white mold. These entries included one to three varieties from 27 different companies/brands. Experiments were conducted at three locations, of which two had severe white mold. In these locations, many varieties were highly tolerant to the diseases with consistent results across locations. Susceptible varieties had 70 to 80 percent plants killed, while many tolerant varieties had only 10 to 20 percent plants killed. Our information sheet ranks varieties for white mold tolerance, level of tolerance, maturity, and yields. Some varieties are high performers in the ISU yield test.

Slide set

This set of 13 slides was developed from my white mold slide collection. It is designed for extension or agribusiness agronomists for presentation at winter grower meetings. It includes three parts:

1. the biology of white mold and how to identify the disease and the disease cycle;
2. how to assess disease risk; and
3. strategies to manage the disease.

The slide set includes a written script. Individual slides can be presented separately or with other slides in a presentation. A small duplication fee will be charged ($10). If you have access to the World Wide Web, go to this address for a complete list of the tolerance results: http://www.exnet.iastate.edu/Pages/plantpath/whitemold.html To get these materials, contact:

XB Yang

351 Bessey Hall

Department of Plant Pathology

Iowa State University

Ames, Iowa 50011

Email: xbyang@iastate.edu

515-294-1741