Common Fruit Tree Pests

Pests and disease are an inescapable part of growing fruit; simply planting a few pears or apples in the garden seems to invite an army of fruit tree pests to turn up and take a bite out of your juiciest produce.

Fortunately, for many of the common kinds you’re likely to come across, there are some very effective treatments available – and half the battle is recognising the tell-tale signs of infection as early as possible.

Caterpillars

A range of caterpillars qualify as fruit tree pests, eating the leaves of apples, pears and plums. The most serious of these are the various kinds of “loopers” – caterpillars named after their characteristic looping movement. They have a voracious appetite for fresh young leaves, graduating to eat petals and the stalks of flowers as the year moves on.

Codling moths caterpillars principally affect apples, but they are also pests of pears and plum trees. Their creamy pink larvae burrow into the core of developing fruit in mid-summer and feed on it from the inside – leaving a sawdust-filled chamber at the centre.

Control is only really practical before the caterpillars enter the fruit – small trees can be sprayed in mid-June with a repeat treatment three weeks later. Alternatively there is a biological control available from specialist suppliers – the nematode Steinernema carpocapsae.

Vapourer moth caterpillars – colourful and hairy – also happily decimate foliage from May to mid-August, while the black and yellow larvae of the buff-tip moth can completely strip a young tree. Other serious fruit tree pests include the caterpillars of the March, Winter and Umber moths.

Some growers use grease bands around the trunks of susceptible trees as a preventative measure, while spraying with pesticides is the most effective method of control if caterpillars have actually been spotted. It’s important to make sure that the product you intend to use is approved for the type of fruit tree you need to treat – so make sure you read the label carefully.

Sawflies

Sawflies affect a number of fruit trees including apples, cherries, pears and plums. The tell tale signs are a scar on the skin as the sawfly maggot burrows into the growing fruit, and a sticky residue on the outside. Their activity ultimately leads fruits to drop early, before they have reached maturity and ripened.

The grubs then leave the fallen fruit and burrow into the ground to pupate and subsequently emerge in the new growing season to repeat the cycle. Cultivating the soil at the base of the trees can help expose the grubs to birds and other predators, while spraying at petal fall can help prevent infestation.

The pear and cherry slugworms – the slimy larval stages of their respective sawflies – attack foliage from early summer to late autumn, leaving papery windows in their upper surfaces. The effect is unsightly, but only really needs action if the problem is severe; a good contact insecticide usually deals with these slug-like grubs very successfully.

Weevils

Blossom weevils affect apples and pears in spring and early summer, grubs feeding within the developing flower buds making the petals go brown and fail to open; later they move to the leaves and continue feeding there. Treatment involves a thorough spraying with suitable pesticides such as pyrethrins early in the spring as the flower buds first emerge, to kill the females before they can lay their eggs.

Woolly Aphid

Although they do not count amongst the really serious fruit tree pests, the feeding activities of woolly aphids – named after the appearance of the white waxy defensive covering they produce – lead to corky galls on the stems, which can often provide an easy point of entry for disease. A spray with bifenthrin should be all that is needed to keep them under control.

A glance through any gardening book will reveal a frightening number of creepy-crawlies, moulds, mildews and diseases that can afflict almost any type of plant – and fruit growers are no strangers to their attentions. Left to their own devices, fruit tree pests can be a serious blight, but with care, vigilance and timely action when necessary, they needn’t ruin your crop.