Webworm larva have been recorded eating around 120 species of hardwood trees  (Bug Guide). Larva however, do differ upon their food choice regional and seasonal.  In the north the larva's common meals  are alder, apple, ash, birch, Box-Elder (Alcernegundo), cherry, elm, mulberry, poplar and willow. While the southern larva chow on ash, hickory, maple, mulberry, oak, pecan, poplar, redbud, sweetgum, walnut, and willow as well. These have been considered amoung the most polyphagous insect.

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The final instar stage, the adult moth, will feast upon flowers, but do not create as much havoc as their larval form. By having this nutritional connection the moths play an important role by being the primary pollinators for these specific flowers.
Adult Hyphantria cunea