Pear blister mite

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

Quick facts

Common name Pear blister mite
Latin name Eriophyes pyri
Plants affected Pear
Main symptoms Many slightly raised pink or yellowish green blotches on the foliage in spring, later becoming blackish brown
Caused by A microscopic gall mite
Timing April-September

What is 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.

Symptoms

Pear trees suffering from blister mite will look as follows;

  • In spring, new foliage develops many slightly raised blisters, up to 3-4mm in diameter, that are reddish pink or yellowish green in colour
  • Later in the summer, these blister become blackish brown
  • The whole leaf can be affected and almost all the leaves on a tree may become blackened
  • The mite does not normally affect cropping or the health of the tree

Control

Fortunately, although heavily infested trees may look unhealthy, the mite has little impact on the tree’s health or ability to produce fruit.

Non-chemical

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.

Chemical

There are currently no pesticides available to home gardeners that are effective against this mite, so its presence has to be tolerated.

Biology

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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