Root aphids on container grown asters

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.  

Jan received a sample this past week from a grower who wanted her to identify the white fungus that was growing on the roots of some container grown asters. When she mounted some of the “fungus” on a slide to study it, she found small yellowish insects amongst her strands of fungus. The white fungus turned out to be the waxy strands produced by root aphids in the genus Pemphigus. The primary hosts of most members of this genus are poplar trees, where they cause galls to form on leaf petioles. During part of the year, they feed on the roots of Compositae.

For a more detail discussion of the root aphids on aster and other perennials see:
http://www.gpnmag.com/Some-Aphids-Go-Deep-Others-High-article2797

Aster roots
Aster roots show the white waxy strands
produced by Pemphigus aphids.
Photo credit: J Byrne, Diagnostic Services.

White waxy material on aster roots
A close up of the white waxy material on
the aster roots. The arrow points to a
Pemphigus aphid. Photo credit: J Byrne, Diagnostic Services.

Root aphid
Here’s a close up of a Pemphigus aphid.
Photo credit: H Russell, Diagnostic Services.

Root aphid under glass
I mounted this aphid on a microscope slide.
Photo credit: H Russell, Diagnostic Services.

Root aphid with babies
This is a close up of the belly of the aphid
showing four baby aphids inside with
their fully developed eyes.
Photo credit: H Russell, Diagnostic Services.

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