Rosy apple aphid

Rosy apple aphid is one of several aphid species that can occur on apple trees, it is often the most damaging.

Rosy apple aphid damage on fruit and foliage

Quick facts

Common name Rosy apple aphid
Scientific name Dysaphis plantaginea
Plants affected Apple
Main cause Sap-sucking insects cause distorted foliage and fruits
Timing April-September

What is rosy apple aphid?

Rosy apple aphid is a small sap-sucking insect that feeds on apple foliage and  fruitlets during spring and early summer. Because it damages fruits even low numbers of aphids can cause significant damage.

Symptoms

Dense colonies of pinkish grey aphids develop on the underside of the foliage in spring and early summer. Affected leaves at the shoot tips become curled and yellowish. Where the aphids have been sucking sap from the fruitlets, they prevent the fruits' normal development. Affected fruits often remain small with a pinched appearance around the eye end. In late summer, some branches may have normal fruits while others have only damaged fruits, reflecting the distribution of aphids on the tree earlier in the growing season.

Heavily infested shoots show stunted growth with distorted leaves that start to turn brown during the summer. The main damage is to the developing fruits, which can be severely undersized and malformed.

Control

Non-chemical control

  • Light infestations can be tolerated as measures such as manual removal of the aphids is not usually feasible
  • Research indicates that earwigs on fruit trees can reduce aphid numbers and in fruit trees they do not cause damage. Providing shelters such as flower pots loosely stuffed with hay in trees can help increase earwig numbers

Chemical control

  • Plant oil winter wash (considered organic e.g. Vitax Winter Tree Wash) can be applied to dormant trees to reduce the number of overwintering eggs. Thorough application is required
  • When the foliage is emerging from the buds an insecticide can be applied to control newly hatched aphids
  • Pesticides with contact action may give some control, these include products based on plant oils and extracts (considered organic e.g. Vitax organic pest & disease control), fatty acids (considered organic e.g. Solbiol Bug Free, Doff Greenfly and blackfly Killer), natural pyrethrum (considered organic e.g. Defenders Bug Killer, BugClear Gun for Fruit and Veg)
  • Synthetic pyrethroid insecticides lambda-cyhalothrin (e.g. Westland Resolva Bug Killer) or deltamethrin (e.g. Sprayday Greenfly Killer) may also give some control
  • Systemic sprays containing the neonicotinoid acetamiprid (e.g. Scotts Bug Clear Ultra) which are absorbed by the foliage may also be used
  • Manufactures instructions for application must be followed for food crops. Thorough application is required and the pesticides must be applied before the aphid has caused leaf curling if there is to be any likelihood of control
  • There is no point in spraying pear trees in mid-summer, when the aphid damage has already occurred
  • Plants should not be sprayed when in flower due to the danger to pollinating insects
  • Inclusion of a pesticide product does not indicate a recommendation or endorsement by the RHS. 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

Rosy apple aphid overwinters on apple trees as eggs that are laid in autumn in bark crevices and around the buds on the shoots. These eggs hatch in spring as the leaves begin to emerge from the buds. While sucking up sap, the aphids secrete chemicals into the foliage and fruitlets, which cause the distorted growth.

Several generations of wingless aphids develop between bud burst and early summer. During June-July, winged forms of the aphid develop that migrate away to wild flowers known as plantains, Plantago species, where they spend the rest of the summer. Infestations on apple die out during the summer but there is a return migration from plantains in autumn when overwintering eggs are produced.

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