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.

Quick facts

Common name Pear midge
Latin name Contarinia pyrivora
Plants affected Pear
Main symptoms Pear fruitlets go black 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 small 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 will turn black and fall from the tree
  • Affected 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

Monitor pear fruit development for midge damage throughout spring. If the midge has been a problem in previous seasons decide if control measures are likely to be needed at the beginning of the season. When choosing control options you can minimise harm to non-target animals by starting with the methods in the non-pesticide control section. If this is not sufficient to reduce the damage to acceptable levels then you may choose to use pesticides. Within this group the shorter persistence pesticides (that are usually certified for organic growing) are likely to be less damaging to non-target wildlife than those with longer persistence and/or systemic action.


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 during dry weather in June and July, 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. It may be possible to tolerate some crop losses.
  • Encourage predators and other natural enemies in the garden such as birds, hedgehogs and ground beetles

Pesticide control

On trees small enough to be sprayed thoroughly, contact insecticides may have some effect if used when the blossom is at the white bud stage (before flowering). This may reduce the number of adult flies and reduce the number of eggs that are laid
  • Organic sprays, such as natural pyrethrum (e.g. Bug Clear Gun for Fruit & Veg, Neudorff Bug Free Bug and Larvae Killer), fatty acids (e.g. Solabiol Bug Free, Doff Greenfly & Blackfly Killer) or plant oils (e.g. Vitax Plant Guard Pest & Disease Control, Bug Clear for Fruit and Veg) These pesticides have a very short persistence and so may require reapplication to keep pear fruit midge numbers in check. Plant oil and fatty acid products are less likely to affect larger insects such as ladybird adults. 
  • More persistent contact-action insecticides include the synthetic pyrethroids lambda-cyhalothrin (e.g. Westland Resolva Bug Killer), deltamethrin (e.g. Provanto Ultimate Fruit & Vegetable Bug Killer, Provanto Sprayday Greenfly Killer)
Follow label instructions when using pesticides. On edible plants make sure the food plant is listed on the label and follow instructions on maximum number of applications, spray interval and harvest interval. Plants in flower should not be sprayed due to the danger to bees and other 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 (pdf document)

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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