Woolly Apple Aphid

Woolly Aphids on American Elms

I recently came across the odd-looking handiwork of Woolly Apple Aphids (WAA) on newly emerging leaves of American elms (Ulmus americana, ‘Princeton’) in southwest Ohio. ‘Princeton’ is an old cultivar first propagated by Princeton Nursery in New Jersey in 1922 that was later found to be resistant to the fungal pathogens behind Dutch Elm Disease (DED).
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Authors
Joe Boggs

Woolly Aphids Add Interest to American Elms

The reemergence and wide use of American elms (Ulmus americana) in Ohio landscapes means we’re becoming reacquainted with some old woolly pests. Today, the point was driven home when I found both woolly elm aphids (Eriosoma americanum) and woolly apple aphids (E. lanigerum) on ‘Princeton’ elms in a landscape in southwest Ohio. Both are native insects that appear in pest records dating back to when American elms were "America's Street Tree."
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Authors
Joe Boggs

Woolly Aphids on American Elm

Thanks to the sharp eyes of Dave Bienemann (Municipal Arborist/Utility Forester, City of Hamilton), I was able to take some nice pictures of the woolly apple aphid (Eriosoma lanigerum) and it's characteristic damage on its alternate host, American elm (Ulmus americana). This isn't the only woolly aphid that uses our native elm as an alternate host. The woolly elm aphid (E. americanum) is another historical American elm pest.
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Authors
Joe Boggs