Aphids on beech
Blackman & Eastop list 12 species of aphid as feeding on beeches (Fagus species) worldwide, and provides formal identification keys.
Of those aphid species, Baker (2015) lists 2 as occurring in Britain:
Lachnus pallipes
and
Phyllaphis fagi
- and they are the only species found on European beech (Fagus sylvatica) worlwide.
Phyllaphis fagi (Woolly beech aphid)
The wingless viviparae are elongate oval, pale yellowish green, covered with wax wool. The antennae are slightly shorter than the body and have a terminal process that is 0.11-0.12 times the length of the base of the last antennal segment.The body length of apterae is usually 2.0-3.2 mm, but summer dwarfs may be down to 1.1 mm. Winged viviparae have the abdomen wax-covered, which conceals variably-developed dark dorsal cross-bars.
The woolly beech aphid is found feeding on the undersides of young leaves of beech (Fagus spp.). This causes the leaves to curl downwards on both sides of the mid-rib, and often to wither and die prematurely. Sometimes numbers are high enough on beech hedges to warrant control measures. This is conventionally achieved by spraying with insecticide.
Danish scientists at the State Forest and Nature Agency have researched more environmentally friendly methods, combining treatment of eggs with winter oil emulsion, use of pathogenic fungi against early generations and release of predators and parasitoids later on. The aphid is distributed throughout Britain and the rest of Europe, east to Turkey and Caucasus. More recently it has been reported from China and Korea, and introduced to Australia, New Zealand and North America.
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Lachnus pallipes (Variegated beech aphid)
Apterae of Lachnus pallipes are shining dark reddish to blackish brown except for the siphuncular cones which are relatively pale. They are large with a body length of 3.0 - 5.0 mm. The abdominal dorsum is densely haired. The middle parts of the tibiae are pale and the antennae are 0.4 - 0.5 times the body length. The alatae have a pattern of forewing pigmentation similar to Lachnus roboris, but with a more extensive clear area between Rs and media.
Variegated beech aphids are found on two-year-old or older branches and stems of beech (Fagus sylvatica). Lachnus pallipes is widely distributed in Britain but seems to be rare. It is found over most of Europe south to Bulgaria and east to Russia and (apparently) the Far East.
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Acknowledgements
Whilst we make every effort to ensure that identifications are correct, we cannot absolutely warranty their accuracy. We have mostly made identifications from high resolution photos of living specimens, along with host plant identity. In the great majority of cases, identifications have been confirmed by microscopic examination of preserved specimens. We have used the keys and species accounts of Blackman & Eastop (1994) and Blackman & Eastop (2006) supplemented with Blackman (1974), Stroyan (1977), Stroyan (1984), Blackman & Eastop (1984), Heie (1980-1995), Dixon & Thieme (2007) and Blackman (2010). We fully acknowledge these authors as the source for the (summarized) taxonomic information we have presented. Any errors in identification or information are ours alone, and we would be very grateful for any corrections. For assistance on the terms used for aphid morphology we suggest the figure provided by Blackman & Eastop (2006).
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References
- Blackman, R.L. & Eastop, V.F. Aphids on the world's plants An online identification and information guide. Full text
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