Pear midge

Pear midge can cause the loss of large numbers of pear fruitlets in spring.

Severe damage caused to a fruitlet by the larvae of pear midge.

Severe damage caused to a fruitlet by the larvae of pear midge.

Quick facts

Common name Pear midge
Latin name Contarinia pyrivora
Plants affected Pear
Main symptoms Pear fruitlets go black, starting at the eye end, and drop off in June. Small maggots may be found inside the fruitlets
Caused by Larvae of a gall midge
Timing May-June

What is pear midge?

Pear midge is a tiny fly with larvae that develop inside pear fruitlets, causing them to turn black and drop off the tree in early summer.

Symptoms

  • Pear fruitlets with pear midge larvae will turn black and fall from the tree
  • Infested pear fruitlets initially grow faster and are softer than healthy fruitlets but during May they begin to turn black at the eye end of the fruit (opposite end to the stalk)
  • The black colour spreads up the fruitlet and it drops off in June
  • A high proportion of the potential crop can be lost
  • Inside the damaged fruitlets are many orange white maggots, up to 4mm in length

Control

Non-pesticide control

  • Look for infested fruitlets and remove them before the larvae complete their feeding and enter the soil to pupate
  • The midge larvae enter the soil when fully grown, where possible hoeing the soil around the base of the tree may reduce survival of the pupae
  • Severity of infestation varies from year to year, in some years very few pears will be affected in others a majority of the crop can be lost

Pesticide control

  • On trees small enough to be sprayed thoroughly, the contact synthetic pyrethroid lambda-cyhalothrin (e.g. Westland Resolva Pest Killer) or deltamethrin (e.g. Provanto Ultimate Fruit & Vegetable Bug Killer) may have some effect if used when the blossom is at the white bud stage (i.e. when the petals can be seen but before the blossom opens). Making to follow the label instructions for the crop. This may control the adult flies and reduce the number of eggs that are laid
  • Plants in flower should not be sprayed due to the danger to pollinating insects
  • Inclusion of a pesticide product does not indicate a recommendation or endorsement by  RHS Gardening Advice. It is a list of products currently available to the home gardener

Download

Pesticides for gardeners (Adobe Acrobat pdf document outlining pesticides available to gardeners)

Biology

The adult flies are tiny midges that emerge in spring, when the females lay eggs in pear blossom shortly before it opens.

The larvae feed inside the developing fruitlets, reducing the centre to a blackish brown mush. The larvae are fully fed by late May-June, when the damaged fruitlets drop off.

The larvae enter the soil where they overwinter inside silk cocoons before pupating in the spring.


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