Arthropod ecosystem services in apple orchards and their economic benefits

Abstract

Apple is grown as a long-term perennial crop and orchards provide relatively stable ecological habitats. Only a small proportion of the diverse fauna of arthropods that can inhabit the orchard ecosystem are important pests, the majority of species being minor pests, beneficial or benign. In this paper, the interacting ecosystem services provided by five contrasting naturally occurring arthropod groups in cool temperate apple orchards are reviewed, and their economic benefits broadly quantified. These are:The roles of bees and other insects in apple pollination increasing yields and fruit quality, the economic value of which may be significantly underestimated. Naturally occurring, pesticide-resistant phytoseiid predatory mites and their role in regulating phytophagous mites. They eliminate the need for 1-2 acaricide sprays per annum and the risk of acaricide resistance. The earwig Forficula auricularia L. and its role in regulating several important apple pests. There is great variability in populations between orchards for reasons not fully understood. It is estimated that F. auricularia reduces insecticide applications by 2-3 per annum and reduces pest damage. Mutualism between the common black ant Lasius niger (L.) and important pest aphids, the roles of competitors, natural and artificial food sources, and ant exclusion in disrupting mutualism which can foster biocontrol of aphids by generalist predators so greatly reducing the need for sprays. Beneficial epigeic arthropods and their role in predating the soil dwelling life stages of insect pests. These contribute to the control of pest populations although the level of suppression is not consistent depending on several ecological factors.