Their life-cycles follow a very specific path, beginning with their eggs infiltrating and spending the winter months in the cracks and crevices in the bark of American elms. Once spring rolls around and the leaves of the elm begin unfolding, the aphid eggs hatch and the aphids begin feeding on the underside of the new leaves. This feeding pattern has two specific outcomes: it first-and-foremost provides nutrients to maturing aphids, but also causes leaves to curl around aphid populations under the leaves, providing protection from natural predators and conventional pesticides.
As summer approaches, the now-mature aphids give birth to an entirely new generation that also begins to feed on the same leaf. The summer months see advanced life-cycle aphids develop wings and leave the protection provided by the distortion of the leaf, in order to locate a new host, which is generally the Siberian, where they give birth to over a dozen young each. These new colonies make their way to the roots of the Siberian to feed and multiply throughout the summer, giving the soil around the root a bluish-purple hue due to a high concentration of waxy secretions produced by the aphids.
With the coming of autumn, the now-winged and fully-mature woolly aphids leave the soil, in order to return to the American elm, where the mating process begins anew, and eggs are once again deposited in the protected crevices and cracks of their original hosts.