Abiotic stressors in the dogwood anthracnose complex

Acidic precipitation reportedly enhances disease severity of dogwood anthracnose (DA) caused by Discula destructiva, on Cornus florida, the flowering dogwood. Seedlings were subjected to acidic fog episodes at pHs 2.5, 3.5, 4.5, and 5.5, using a simulated acidic rain solution. Leaf discs from these and non-treated plants were examined by scanning electron microscopy (SEM). Damage was noted at all pH levels. Discula destructiva conidia may germinate at trichome bases where damage may cause the leaching of nutrients. Also, the difference in stomatal damage may account, in part, for differences in disease susceptibility.

Cardinal growth temperatures and response to thermal stress regimes were determined for isolates of Discula destructiva. This information may lead to an understanding of possible climatic barriers, and the thermal treatment of plant material.