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Hogweed mealy root aphidIdentification & Distribution Biology & Ecology Damage & Control
Identification & Distribution:Adult apterae of Dysaphis newskyi are pinkish to lilac grey and wax dusted. Hairs on the third antennal segment are maximally 27-56 μm long, distinctly longer and more acute than those on abdominal tergite 3. The antennae always have secondary rhinaria (12-55 on segment III, 0-20 on IV and 0-3 on V). This is a good distinguishing character from Dysaphis lauberti which only has secondary rhinaria in alatiform apterae with dark cross bands on abdominal tergites 1-4. The siphunculi are 1.2 - 2.6 times the length of the cauda. The body length of Dysaphis newskyi apterae is 1-5-2.7 mm.
Abdominal tergite 7 almost always has a pair of marginal tubercles.
Dysaphis newskyi does not host alternate, but lives all year round on hogweed (Heracleum spp.). It can be found in ant-attended colonies on the basal leaf sheaths and root collar of its host. The species has been found in Britain, Austria and Italy and more recently in Poland and Finland.
Biology & Ecology:
Dysaphis newskyi is the only non host-alternating Dysaphis found on hogweed (Heracleum spp.) in Britain. The other species host-alternate with hawthorn. Hogweed (see picture below) is fairly easy to distinguish from other umbellifers by the unequal petal sizes on flowers near the outside of the umbel.
Dysaphis newskyi is seldom recorded in Britain, and our record is the first for southern England. Baker (2009) found it in Wales feeding at the root collar of Heracleum sphondylium in Porthkerry Park, Barry. The aphids were sheltered and attended by Lasius niger and Myrmica ruginodis. Blackman (2014) notes it has also been found in north-east England and Scotland.
The picture above shows a (rather disturbed) colony of the hogweed mealy root aphid that we found at Winchester Beach in East Sussex.
The nymphs are a rather beautiful pinkish-yellow colour. Those below were living protected in a cavity in the hogweed root.
Hansen et al. (2006) noted that Dysaphis newskyi was one of the few insects that is monophagous on Heracleum species, and hence potentially valuable as a natural enemy of the invasive giant hogweed (Heracleum mantegazzianum).