Woodland Health:Foliar Anthracnose Diseases of Deciduous Hardwoods

摘要

Anthracnose diseases of trees and shrubs are caused by a dynamic group of fungal pathogens that vary in their host specificity "and ability to cause disease. Anthracnose fungi are taxonomically diverse and many new species are still being discovered today. To illustrate this point, there are at least five different species of fungi that cause anthracnose of birch in northern temperate forests. All anthracnose fungi attack the foliage of susceptible trees and infections result in the developmentof spots, blotches, marginal blight or a total collapse of the foliage. Trees with compound leaves may have the petiole attacked, resulting in wilt and premature shedding of large volumes of foliage. A subset of anthracnose fungi can also infect flowering parts, fruit, current season's stems and even small branches. Sycamore anthracnose kills the terminal buds on infected trees, causing the lateral buds to flush and compete for dominance. This perennial pattern of damage results in thedistinctive right-angle branching structure that American sycamore exhibits. The non-native pathogen responsible for dogwood anthracnose (Discula destructive^ causes shoot blight and perennial branch cankers that weaken and ultimately kill flowering dogwoods. Typically, anthracnose fungi are not primary pathogens that kill trees in forest settings, but more often secondary agents that contribute to growth loss and decline.