BOTANY 123 Study Guide - Final Guide: Emerald Ash Borer, Dutch Elm Disease, Bark Beetle
Document Summary
Fading forests: tree disease and pest epidemics and their societal and ecological consequence. Is a wilt fungus, grows in the sapwood: primarily vectored by bark beetles, also spreads through root grafts of trees growing close to each other, devastated elms across north america in both urban areas and forests. Estimated 77 million street trees killed in us by 1970: replaced by other species, many were ash trees Larvae girdles the tree by tunneling and feeding underneath bark. Introduction usually in port cities: human vectors are very important, wood products are an important long-distance transport mechanism. Spread depends on landscape makeup - barriers, transportation corridors: quarantines can be effective but not 100% Hosts have no acquired or genetic immunity or resistance. No natural control by predators or pathogens as in native habitat. In some cases management has created monocultures of trees all the same age: also pollution and climate change can have an impact.
