The Effect of Fungicides on Vesicular-Arbuscular Mycorrhizae

Abstract

Two experiments were conducted to survey the effect of certain fungicides on vesicular-arbuscular mycorrhizae. In Experiment I, peas and onions were planted in field soil treated with captan, zineb, benomyl, and Cyprex at concentrations from 20 - 80 ppm. The plants were raised from seeds under greenhouse conditions. Concentration of fungicides and fungicide type were found to have a significant effect on mycorrhizal infection in certain cases. Experiment II was designed to determine the effect of fungicide type, application technique, and the interaction of these factors on mycorrhizal infection. Peas, onions, and soybeans were treated with captan, zineb, benomyl, and Cyprex under normal field conditions. Although results were not consistent among species, all factors tested significantly affected mycorrhizal infection in at least one species. It is suggested that more data from field investigations are needed before general conclusions can be made, and that the interaction of plant species and fungicide may be an important factor in determining effect on mycorrhizal infection.