European Weeds and Insects in America

Abstract

A CANADIAN friend writes to me:—“I leave heard or seen it mentioned as a fact that European weeds and insects introduced into America flourish for a while, but after fifty or sixty years gradually disappear: for instance, that the Hessian fly (so called from having been brought over by the Hessian troops in their hay in the war of independence) has died out or ceased to give trouble, though at one time it totally destroyed the wheat crops of New England. I do not know how far the facts have been tested, or how far they are owing to improved agriculture.”