

When fire blight-resistant cultivars are exposed to the pathogen, it will not spread More information about eachįactor is provided below. Presence and spread of fire blight in a given orchard. This fire blight risk tool can help growers determine their general risk based on factors contributing to the The bloom period (typically increases with the number of cultivars planted), treeĪge and vigor, local presence of fire blight, and risk of infection based on heatĪnd humidity during bloom. The risk of fire blight in an orchard depends on cultivar susceptibility, length of Risk Factors Contributing to Fire Blight Infection Where infection has overwintered, providing inoculum for future infections.


The photos above and below are of early spring infections in flower buds and cankers Infected plant matter can be submitted to the lab through your Montana extension office. MSU's Schutter Diagnostic Lab can identify and confirm fire blight present in orchard specimins. Michigan State University provides a thorough guide on scouting for blossom blight symptoms of fire blight in apples for early detection. WSU Fire Blight guide offers comprehensive identification information in addition to management resources. Early detection is an important aspect of controllingįire blight. Later, infected fruit oozes and branches develop cankers. As the pathogen spreads,īranch tips will appear scorched and droop with the characteristic “shepherd’s crook.” Once infected, blossoms may appear shriveled or frost-damaged. Fire blight spreads between trees primarily by insects and secondarily by wind In addition to infecting pears and apples, it can affect other members of the Rosaceaeįamily, including native mountain ash, serviceberry, raspberry, cotoneaster, and hawthorn Vulnerable to the disease, which thrives under warm (70-90☏) and humid conditions. It infects pear and apple blossoms and can rapidly spread through the tree, killingīoth the scion and the rootstock of susceptible cultivars. Fire blight ( Erwinia amylovora) is a major bacterial pathogen of apple trees in Montana (Zidack et al.).
