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Pear trees sometime develop distinctive raised pink or yellowish green blotches which usually turn black on their leaves during the spring and summer. This is a sign of a pear blister mite infestation.
Pear blister mite
Pear blister mite is a microscopic mite that feeds within the foliage of pear trees.
Similar mites can be found on Sorbus and other Rosaceae trees, these are different species to that found on pear.
Pear trees suffering from blister mite will look as follows;
Fortunately, although heavily infested trees may look unhealthy, the mite has little impact on the tree’s health or ability to produce fruit.
In light infestations infested leaves or shoots can be removed, this may stop the mite spreading all over the tree. Taking infested leaves off a heavily affected tree will do more harm to the plant than the mite.
There are currently no pesticides available to home gardeners that are effective against this mite, so its presence has to be tolerated.
The mites overwinter underneath the outer bud scales on pear trees.
In spring, the mites emerge and penetrate into the developing foliage. They feed by sucking out the contents of the leaf cells and while doing so, they produce secretions that create small discoloured blisters around where the mites are feeding.
The mites spend the summer feeding and breeding inside the leaves but come out and to seek overwintering sites before leaf fall.
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