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Aphid predator (Hemiptera : Miridae)
Phylus coryliOn this page: Identification & Distribution Biology & Ecology Biological Control of Aphids
Identification & Distribution
Adult Phylus bugs are fairly long and slender. Phylus coryli has forewings that vary from light brown to black, with the cuneus usually (but not always) slightly reddish. The head is black. (cf. Phylus palliceps which has red to yellow-red forewings and a yellow to pale brown head) (cf. Phylus melanocephalus which has yellow to orange-red forewings and a dark brown or black head). Adult length is 4.5-5.5 mm.
Phylus coryli is found on hazel (Corylus avellana), whilst the related species Phylus palliceps and Phylus melanocephalus are found on oak (Quercus). All three species are zoophagous and phytophagous. Phylus coryli is widespread in Europe through to the Caucasus, but it missing from parts of southern Europe.
Biology & Ecology
Ecevit (1992) studied the ecology of Phylus coryli on hazelnuts in Turkey. Males and females of Phylus coryli were predators of the small hazel aphid (Myzocallis coryli). Immature Phylus coryli appeared in mid-April and consumed approximately 10 aphids/day for a 10-day period. Adults were present from late May to late June. After June, eggs were laid at the bases of plants.
We have observed Phylus coryli predating large hazel aphids (Corylobium avellanae) on hazel (see picture below).
In this case the bug is investigating a dead aphid, although it was not clear whether it was the remains of a previous meal, or an aphid that had been killed by Entomophthora fungus. Phylus coryli are known to be scavengers of dead aphids as well as predators of live aphids. Wheeler, 2001 gives numerous examples of mirids scavenging, and notes that necrophagyis a strategy that helps mirids minimize the effects of low nitrogen levels in host plants. It may also be energetically more efficient than actively hunting for live aphids.
As well as several instances of finding Phylus coryli predating hazel aphids, we have also found them on umbellifers in hazel-rich woodland consuming large numbers of Cavariella aphids (see picture below).
Biological control of Aphids
Phylus coryli feeds on small insects and on hazel, but without damaging the hazelnut crop. In hazelnut orchards it is one of eight beneficial mirid bug species which aids in the control of pests (Guidone et al., 2008 ).