Authors: Van Driesche, R.G., J.H. LaForest, C.T. Bargeron, R.C. Reardon, and M. Herlihy. 2012. Forest Pest Insects in North America: a Photographic Guide. USDA Forest Service. Forest Health Technology Enterprise Team. Morgantown, WV. FHTET-2012-02.
Orientation to Pest
Woolly beech aphid, Phyllaphis fagi (L.), is an invasive aphid in North America, likely of European origin. It feeds on all species of beech, but high densities are usually only found on European beech (Fagus sylvatica L.), which is widely used in landscape plantings. The aphid is usually not a problem in the United States on the American beech, Fagus grandifolia Ehrh., growing in forests or low stress sites. This woolly aphid, which feeds on the undersides of leaves can be confused with the beech blight aphid (Grylloprociphilus imbricator [Fitch]), which begins feeding on the leaves and then moves onto stems. The woolly beech aphid eggs hatch in the spring and there are about ten generations per year of apterous and winged forms, which occur together. Huge populations can occur year after year without causing visible harm to the tree. The massive amounts of honeydew produced by large colonies can be a nuisance.
Hosts Commonly Attacked
This aphid is found most often on European beech (Fagus sylvatica L.) planted in urban or residential landscapes.
This aphid is widely distributed in both eastern and western North America, where ever beech is grown.
Biological Control Agents
The braconid parasitoids Praon flavinode (Haliday) and Trioxys phyllaphidis Mackauer are known to attack this species in Europe, but are not reported from North America.
- Iversen, T. and S. Harding. 2007. Biological and other alternative control methods against the woolly beech aphid, Phyllaphis fagi L., on beech, Fagus sylvatica, seedlings in forest nurseries. Journal of Pest Science 80: 159-166.