The pests that matter in a cider orchard

Rosy apple aphid, Dysaphis plantaginea, overwinters as eggs on apple bark and hatches around bud burst. Colonies feed on the developing leaves and shoot tips, injecting saliva that causes severe leaf curl and shoot distortion. Later in the season the aphids migrate to plantain as a summer host and return to apple in autumn to lay.

The damage that matters is to the fruit. Feeding near developing fruitlets produces small, hard, misshapen apples that never size properly, and the effect persists for the rest of the season after the aphids have gone. A heavily infested tree can carry a crop that looks like a crop and weighs a fraction of one.

It is also the pest where the difference between orchard systems shows most clearly. In a bush orchard it is monitored and treated. In an unsprayed traditional orchard, control depends on the predators the orchard supports — earwigs, hoverfly and lacewing larvae, ladybirds, and the tits that work the buds in spring — which is one of the more concrete instances of orchard biodiversity doing agronomic work.

Woolly aphid, Eriosoma lanigerum, forms conspicuous white waxy colonies on bark, and the swollen galls its feeding produces crack open and provide entry points for canker. Its importance in a cider orchard is largely indirect and runs through the canker it enables. Some rootstocks carry resistance to it, which was one of the original selection criteria for the Malling-Merton series.

Apple blossom weevil, Anthonomus pomorum, lays into unopened flower buds and its larva destroys the flower from within, leaving a characteristic capped brown bud that never opens. It is more prominent in unsprayed traditional orchards, particularly those near woodland where the adults overwinter, and in a bad year it removes a meaningful share of the bloom.

Apple sawfly larvae tunnel into fruitlets and cause them to drop in early summer, leaving a distinctive ribbon scar on fruit that survives. Codling moth larvae enter later and tunnel to the core. Winter moth caterpillars feed on buds, blossom and young leaves in spring and can defoliate badly in a heavy year. Fruit tree red spider mite bronzes foliage in hot dry seasons, usually after a broad-spectrum spray has removed its predators.

A dessert grower treats to protect appearance, and the tolerance for a codling moth entry hole is effectively zero because a single tunnelled apple in a pack is a rejected pack. A cider grower has no such constraint, and the correct threshold is set by yield and by rot risk instead. This raises the intervention threshold for several pests by a large margin, and it removes it altogether for some.

The consequence is that cider orchards are, on average, treated far less than dessert orchards, and that this is a rational response to the crop rather than an ideological position. It also means cider orchards retain more of the predator and parasitoid fauna that regulate pests, which further reduces the need to intervene — a genuinely virtuous loop, and one of the reasons unsprayed traditional orchards are not overwhelmed by pests despite receiving no protection at all.

The exceptions are the establishment period and the pests that damage the tree rather than the fruit. A rabbit that rings a maiden has killed it, and no threshold argument applies. Protection of young trees is not optional in any system.