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woolly ash aphid




Biological Control

Chemical Control











Woolly ash aphid is a key pest in nursery production of ash, Fraxinus spp. Damage from aphid feeding can be severe and lasting. Although this pest is relatively common, little information of its activity in nurseries and landscapes has been published.

Most of the aphids described on ash are in the tribe Pemphiginae. Some Pemphigid aphids can infest the root systems of conifers. These aphids are described as woolly aphids due to the light colored waxy strands secreted by some stages.

There are several species of aphids that have been listed as occurring on ash trees (Blackman and Eastop, 1994). Walker (1969) mentions Procipihilus (Pemphigus) americanus Wlk. specimens collected from ash in California, Colorado, Oregon, Utah, and Canada. In the Northwest Zak (1965) mentions P. americanus using ash as an alternate host in rotation with Noble fir, Abies procera Rehd. The aphid, Prociphilus fraxinifolii, (Meliarhizophagus fraxinifolii) occurs on the roots and leaves of ash trees in a mutualistic asociation with the ash-tree bolete fungus Boletinellus merulioides (Grundrett and Kendrick, 1987). In California, P. fraxinifolii, is reported on Modesto ash, F. velutina (Anonymous, 1998). Carver (1980) reports on a parasite of P. fraxinifolii (Riley) on ash in Iowa. In Sichuan Province in China, the aphid Prociphilus fraxini (F.) occurs on chinese ash, F. chinensis, occasional outbreaks causing considerable damage. P. bumeliae are reported from European Ash, Fraxinus excelsior (Blackman and Eastop, 1994). White Ash, Fraxinus americana, are listed as hosts of P. americanus, P. fraxinifolii, P. oriens, P. pergandei, and P. probosceus (Blackman and Eastop, 1994) . Green Ash, F. pennsylvanica, host P. americanus, P. fraxinifolii, and P. probosceus (Blackman and Eastop, 1994). Essig (1911) describes populations of P. americanus (Pemphigus fraxini-dipetalae) from California Mountain Ash, F. dipetala.


Last modified - 4/23/03


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