Left - Discula destructiva, a fungus believed to cause anthracnose. Right - an undescribed species of Discula which also causes anthracnose. Plants are able to survive because they contain chlorophyll to make food. Once the fungus is on the dogwood tree, it releases a substance that breaks down the complex structure of dogwoods into something the fungus can absorb and use for growth, energy, and reproduction. The fungus also releases toxins that kill the leaves of the tree, can spread into the stem to infect new limbs and can cause cankers.
Researchers can remove a sample of the fungus from the tree.
The photos above show the difference between the fungi. You have probably heard about the use of DNA to identify both victims and criminals. The use of DNA to identify the type of fungus on dogwood trees was developed at the University of Tennessee. DAF is like looking at the bar code on a coke can to borrow an analogy from Dr. Peter Gresshoff. Bar code from a Pepsi can.