These cultivars are moderately resistant:Īll strains of ‘Delicious’ are highly resistant to fire blight, except when tissues are damaged by frost, hail, or high windsįor more information, see Table of Apple Cultivar Relative Fire Blight Susceptibility. Of the apple varieties planted in the eastern region, those that are most susceptible include: Trees most susceptible are those under drought stress. Branches die back and become covered with dark-brown to black, pimple-like fungal fruiting structures. Leaves on affected branches wilt and die. Fire blight can destroy tree limbs or the entire tree in severe cases. It can spread by splashing water or by insects (including honeybees) more so in warm, humid conditions. An apple rootstock study was established at the Chilton Research and Extension Center near Clanton, Alabama in 2014 as part of a multistate NC-140 project. The destructive potential and sporadic nature of fire blight, along with the fact that epidemics often develop in several different phases, make this disease difficult and costly to control. Informational table showing disease name, symptoms, pathogen/cause, and management of Crabapple diseases. Fire blight is a bacterial disease that affects apple trees, pear trees, and other members of the Rosaceae plant family. This erratic occurrence is attributed to differences in the availability of overwintering inoculum, the specific requirements governing infection, variations in specific local weather conditions, and the stage of development of the cultivars available. Rootstock or collar blight of apple is an important phase of fire blight, but only when susceptible trees are grown on highly susceptible rootstocks (VAN. Below are some apple tree varieties that show moderate to high resistance to fire blight make sure they are hardy to your plant growing zone before purchase: Ace Delicious Arkansas Black. Outbreaks are typically very erratic, causing severe losses in some orchards in some years and little or no significant damage in others.įigure 2. Apple shoot with fire blight showing typical “shepherd’s crook” symptom associated with wilting. Trees that bloom later in the season (when temperatures are warmer) are more likely to get severe blight damage. The disease is generally common throughout the United States wherever apples are grown. Biggs, West Virginia University)įire blight is a destructive bacterial disease of apples and pears that kills blossoms, shoots, limbs, and, sometimes, entire trees (Figs. Crabapples (Malus spp.) are susceptible to several diseases, most prominently apple scab, fire blight, powdery mildew, and cedar apple rust.The International Ornamental Crabapple Society, a network of public gardens with extensive crabapple collections, assesses these flowering trees annually for disease resistance as well as aesthetic qualities. Understanding the genetics of the disease resistance. Figure 1. Blossom cluster and adjacent shoot with fire blight. The introduction of wild species traits into cultivars is a slow process in fruit tree breeding.
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