A wide range of plant covers and interplanted peach trees were tested by the authors (Tab. II). Most of the tested assemblages aimed at providing beneficial arthropods with pollen and nectar through flowers or peach nectaries. Grassy or flower strips sown in the orchard alleys (between rows) are proposed in apple orchards to help control the rosy apple aphid Dysaphis plantaginea. Single species covers with buckwheat, phacelia or alyssum were experimented on in New
Zealand to help control Tortricidae.Weeds are also companion plants in orchards and may shelter natural enemies ,especially flower weeds. The plant cover not only shelters an abundant arthropod community likely to offer alternate preys or hosts, but also orchard pests: aphids, mites, phytophagous mirids, leafhoppers, tortricids and Coleoptera. However, the migration of these pests towards the cultivated trees is often more affected by the management of the plant cover than by the plant cover itself: weeding leads the hosted pests to migrate towards another resource, i.e. orchard trees. Natural enemies hosted by the plant cover of the alleys are also negatively affected by frequent mechanical mowing.