There are few specific cultural controls for apple-grass aphid. Natural enemies should be encouraged by avoiding the use of broad-spectrum insecticides and by providing flowering plants in and around the orchard. Artificial refuges can be provided for predators. High nitrogen levels in the tree favour apple grass aphid.
Natural enemies
Predatory insects and spiders
- A wide range of predatory insects, including anthocorid, mirid and nabid bugs, ladybird adults and larvae, hoverfly, predatory midge and lacewing larvae and spiders feed on apple grass aphid in spring.
- The aphid often provides an important early food source which increases predator numbers for natural regulation of other pest species.
- Spiders and earwigs are more important as natural enemies of the returning migrants and their offspring in the autumn.
Parasitic wasps
- The parasitic wasp Monoctonus mali is the most important parasitoid of apple grass aphid, though there are several other less important species including Ephedrus persice, Ephedrus validus, Praon necans, Praon volucre and Trioxys auctus.
- The parasites lay their eggs (usually singly) in the body of the aphid which continue to feed during the early stages of development of the parasite.
- The parasites eventually pupate within or beneath the skeleton of the aphid forming a so-called ‘aphid mummy’.
- Monoctonus mali is a host-specific parasite which has two generations on apple grass aphid in spring before entering a summer diapause when its host begins to migrate to grasses.
- Although parasitic wasps are common natural enemies of apple grass aphid, they are not usually abundant enough to greatly reduce aphid populations.
Biological control
Biological control approaches have not been developed for apple grass aphid.