What causes dogwood anthracnose?
The fungus that causes dogwood anthracnose, Discula destructiva, was named and described in 1991 (Redlin, 1991). The fungus grows slowly in culture, and exudes spores from fruiting bodies both in culture and on leaves. I sent samples from Connecticut leaves and twigs to various mycologists for comparison, and they confirmed that the fungus present on our dogwoods was indeed D. destructiva. Even though the Connecticut fungus was identical to those in other locales in the U.S. where dogwood anthracnose was rampant, I did not observe the severe dieback and decline symptoms on dogwood that researchers in other states had attributed to anthracnose infection. In addition, I experienced difficulty in reproducing symptoms by artificially inoculating healthy dogwood trees. However, due to the consistent association of the fungus with diseased dogwoods, I accepted that this was the fungus causing leaf blight and twig dieback on our dogwoods.