Fungus on fruit trees can destroy your crops and leave your trees in decline. Planting fruit trees resistant to fungus is ideal as it allows the prevention of infection in the home garden. With the vast array of fungi, fungal strains and fruit tree varieties, getting an idea of some main constituents in the fight against fungal infections will set you on track toward a landscape full of vigorous fruit trees.
Resistance Through Care
Caring for fruit trees raises resistance whether or not the tree is naturally resistant against the particular fungus in question. Trees that are not provided adequate culture or maintenance experience diminished health and are much more vulnerable to fungal infection than healthy trees. Additionally, trees that are already sick with a disease or pest infestation are that much more likely to become infected by fungus. Provide your fruit trees with the sun exposure they need for proper growth. Soil is highly important, particularly drainage, as waterlogged soil often depletes water and nutrient absorption in trees and promotes the germination of fungi.
Level of Resistance
Fruit trees that are susceptible to fungus are those that are vulnerable and more likely to experience infection, according to the Virginia Cooperative Extension. Depending on common fungi that thrive in your region's soil as well as whether you plant a fruit tree in the appropriate USDA hardiness zone, resistance varies. Keep in mind that "resistant" does not mean "immune." To determine the level of resistance of fruit trees in your particular location, contact your local county extension agent or a licensed professional who applies fungicides.
Fruit trees resistant to fungus are perfect replacements for those trees that are susceptible to fungus. If you have already experienced the severe illness or death of a tree in infected soil, you know not to replant the same type of tree. After tree removal, the best option for replanting is with a resistant variety that will not suffer the same infection, according to the University of Minnesota Extension.
For soil-borne fungus, your need for application of preventive fungicides greatly decreases with resistant fruit trees. However, precautionary application of fungicides on resistant trees provide a home grower with an even greater sense of security since the likelihood of infection is already low. Verticillium wilt, for example, is a soil-borne fungus caused by the fungi Verticillium albo-atrum and Verticillium dahliae. Common fruit trees with reported resistance are apple and pear, according to the University of Minnesota Extension.
Foliage and Flower Fungus
For a fungus problem that infects the foliage and flowers of fruit trees as opposed to through the soil, sporadic spreading of fungi often makes predicting infection difficult. Powdery mildew is one common type of fungus that affects a wide variety of woody ornamentals, including fruit trees. Repeated fungicide applications are often necessary for susceptible trees. Resistant fruit trees include an extremely wide variety of crabapple tree cultivars including, but not limited to, Adirondack, Beauty, Golden Raindrops, Harvest Gold and Purple Prince, according to the Virginia Cooperative Extension.