Title: Managing Fungicide and Bactericide Resistance in Plant Diseases
Description: Mark Longstroth, District Extension Educator for Horticulture and Marketing, MSU Extension
Abstract:
Here in Michigan fruit growers are beginning to understand that many of the very effective materials that they have used for 5 to 10 years no longer work as well as they used to work. It is apparent that there is resistance in apple scab, cherry leaf spot, black rot of grapes and sevreal othe fruit diseases to materials that seemed to be wonder drugs 10 years ago.
Growers and pest management consultants need to be concerned about fungicide and bactericide resistance and should incorporate strategies to delay the development of resistance in plant pathogenic diseases. In Michigan, we have documented examples of materials which are no longer effective because of resistance in the pest population. Dodine (Syllit), benomyl (Benlate), and thiophenate-methyl (Topsin-M) are no longer recommended for apple scab; streptomycin resistance has appeared in fire blight; and copper resistance is common in bacterial canker.