Twisted Elm Leaves

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