THE POPULAR SCIENCE MONTHLY.
|THE ENEMIES WE IMPORT.|
By Prof. SAMUEL LOCKWOOD, Ph. D.
IT would seem as if every grain brought its bane. The Agricultural Department at Washington has done a good deal for agriculture in the importation and distribution of foreign seeds, slips, and plants. In this way have been secured to the country many of the choicest improved plants from abroad, and many entirely new to our gardens. But it is to be feared that, in some instances unavoidably, and in others from want of care or skill, or both, the eggs and larvae of foreign insect-pests have been introduced, and are to-day troublesome to the husbandman, and a source of mischief and loss to the interests of the nation at large. If that man, or that art, is a public blessing that makes a spear of wheat grow where the land was sterile before, or makes that bear twofold that before did little more than barely reproduce its kind, surely, then, that is a pest and misfortune that appears as a new destroyer of the anticipated harvest. So far as size is considered, the little fly introduced in the provender of the Hessian soldier, in 1776, is contemptible; yet it was destined to become an enemy more formidable than the troops that brought it. So diminutive, indeed, is this pest, that many a husbandman has never seen it to know it, and, in fact, only knows it from its sad depredations on his honest labor; which are such that all the combined whirlwinds and destructive storms that have ever swept over portions of our land have not robbed the national wealth so much as this almost invisible, tiny creature, that dances in the sunbeam; which science well names Cecidomyia destructor, and which tradition calls the Hessian fly.
In Freehold, N. J., in the autumn of 1870, I detected a new-comer making terrible havoc with the cabbage. This esculent was entered from without, and almost honey-combed by a small green caterpillar, that I had never seen before. It was soon determined to be the Pieris rapae, or cabbage-caterpillar of Europe. The parent was a pretty butterfly, mainly white, with black spots on the wings. It first appeared on this continent at Quebec, and made its noxious power felt in the destruction of the cabbages to the amount of many thousands of dollars in that neighborhood. It soon came into Northern New England, and in 1869 was found in the gardens within a few miles of New York. At Freehold, of course, it was stretching south. It soon reached Philadelphia. Last summer it was at home at Baltimore, and this June it has appeared at Washington. The terrible little beauty is thus belting the land with a scourge.
Among the insect pests that have become celebrated because of its fearful capacity of increase, the grasshopper deserves mention. It is