Help me find psyllids on Beaked Hazelnut (Corylus cornuta)

Background. Members of the birch family (Betulaceae) are a common host plant for psyllids in North America. All species associated with plants in this family are now referred to the genus Psylla, and include Psylla alni, P. viridescens, P. caudata and P. floccosa on Alder, P. striata, P. hartigii, P. betulae and P. betulaenanae on Birch, and P. carpinicola on Hornbeam. Many of these psyllids are relatively frequently observed, due to their large size in addition to the rather conspicuous nymphs which are usually covered in dense white fluff. One additional psyllid belongs to this group: P. diloncha, which is recorded from from the plant historically referred to as Corylus rostrata but is today known as Corylus cornuta, or Beaked Hazelnut.

Beaked Hazelnut (Corylus cornuta) is a somewhat common tree that grows in the eastern and midwestern USA into western Canada and south along the west coast into California. The recorded distribution of Psylla diloncha mirrors the host distribution, with records from Minnesota, Wisconsin, Ohio, Alberta, and California. Historical records from Kansas and Nevada also exist but seem to be outside of Beaked Hazelnut's current native range.

Original descriptions and illustrations of P. diloncha would suggest that it is most similar to the birch psyllid P. striata, but with genal cones very long and with the pterostigma almost entirely lacking. It may also be similar to the hornbeam psyllid P. carpinicola, but with the cubital cell less strongly arched and probably with the wings a bit more yellowish.

To date, I can find no example of photos on iNaturalist or Bugguide which are convincingly suggestive of this species, so perhaps that's where you come in. If Beaked Hazelnut is in your area, try investigating it for these psyllids; at this time of year, adults are expected. Nymphs are likely to also cover themselves in conspicuous white fluff like other members of the genus, but it is not known when nymphs may be found. Photos of this species will advance our understanding of this genus and will also be an iNaturalist first.


Beaked Hazelnut leaves. C. Mallory


Psylla striata adult © Stuart Tingley, some rights reserved (CC-BY-NC). Psylla diloncha is expected to look similar to this species.


Psylla viridescens nymphs on alder. © Masumi Palhof, some rights reserved (CC-BY-NC). Psylla diloncha nymphs may be similar

Posted on 04 July, 2022 02:07 by psyllidhipster psyllidhipster

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Potentially 100s of Corylus cornuta on my stomping grounds, so you know I'm game! Even though I explore the leaves regularly, I just found a new mirid this past week. This one:
https://www.britishbugs.org.uk/heteroptera/Miridae/phylus_coryli.html
Wish me luck -- I'd love to find this psyllid for you!

Posted by harsiparker over 1 year ago

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