Pear trees not only make wonderful ornamental trees, but also produce delicious fruit when well maintained and free of disease. Rust is a common pear tree infliction caused by fungi. There are over 2,000 species of fungi rust that cause harm to fruit trees. Harvests produce smaller yields, sugar levels in fruit are reduced and defoliation occurs to the leaves. Defoliation or leaf loss causes the tree to live off of food reserves that result in adequate food sources for bud development and premature blossoming.
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Inspect the leaves of your pear tree for orange spots in May. Summer climate promotes rapid growth in the fungi spores, which can cause spots to grow up to one centimeter in diameter. Black spots will soon develop in June, and by August the leaves with thicken with spores. Be sure to inspect underneath the leaves. Large orange jelly like swellings on the tree are further indications that the tree has rust.
Examine all junipers and pear trees in the local area. Both junipers and pear trees are susceptible to pear trellis rust. Fungal spores can travel long distances when dispersed. It is important to treat not only your cultivated pear trees, but any nearby infected trees.
Spray a fungicide on your pear tree. Fungicides have a low rate of treating rust, yet may occasionally be effective when the rust is sprayed early. Be sure to spray underneath the leaves and to repeat the procedure in a couple of weeks.
Prune any diseased branches with sharp pruners, loppers or pruning saw. Dip your pruning tool in a mixture of 70 percent denatured alcohol and 30 percent water to avoid spreading the fungal spores. Make a 45 degree downward cut close to the branch collar when removing entire branches. Cut to a healthy bud when trimming portions of the branch.
Remove any fruit, leaves or branches from underneath pear trees. Place the debris in a garbage bag or burn. Leaving any diseased portion of the tree will continually infect healthy portions of the tree.
Prevent fungal infection to your pear trees by removing any wild diseased trees.
Examine all pear trees for rust from nurseries before purchasing.