WHEAT INSECT PESTS. Insects in jurious to growing wheat-crops. These number from 50 to 100 different kinds in the United States many of which have been imported from the rt ld World; and they represent a wide va riety of forms and classes. The most impor tant, probably, are flies, more or less closely re lated to the house fly and mosquito; and of these the Hessian fly is the most dreaded and widespread. This is a small fly (Cecithnnyia destruttor) of the family Cecidoinyider, the larva of which is very destructive to wheat, barley and rye, but does not attack oats. It is named from the unfounded belief that it was brought to America from Europe (where it is native, and has been a pest for centuries) in the baggage of the Hessian mercenaries em p*ed against the Americans in the war of independence. The female fly is about a tenth of an inch in length. Its body is brown, with the upper parts, the thorax, and the had of a darker shade, approaching to black. The wings are dusky gray, and are surrounded with fringes. The male is somewhat smaller than the female and has longer antenna. The fe male flies usually lay their eggs on the young plants twice in the year, in May and September, the maggots being hatched in from four to 14 days. These work themselves in between the leaf-sheath and the stem and fix themselves near the lowest joints, often near the root, and suck the juices of the stem_, so that the ear falls down at a sharp angle. These maggots turn to pupa ('flaxseed') from which the flies develop in about 10 days; those of the fall brood hibernate in the pupa state, and are ready to begin their depredations with the early sprout ing of the spring crop. In view of these habits, wherever the presence of these insects is known or suspected, the winter wheat should be planted as late as possible, or the early ph nfing of a "trap' strip at one side of the field In this the flies will lay their eggs, after which the strip may be plowed under and the destroyed: volunteer wheat should be and stubble burned.
Other true flies attacking wheat and other grain-crops are mainly of the family Oscinider which contains a large number of species of variable habits, those of interest in the present connection mainly inhabiting the sterns of grain and grasses. Here belongs the frit-ay of Europe, so terribly destructive both in Great Britain and on the Continent, and many species in this country whose depredations are insig nificant or local or obscure. That one of most consequence, and most thoroughly studied is the •wheat bulb-worm' or "wheat stem-maggot' (Meronsys americana), which has been a cos stant evil ever since civilized agriculture began here. It is a native of the whole of Norsk
America, apparently, originally feeding on the wild grasses. In the middle latitudes of the United States three annual broods develop; there are more farther south, but only two in Canada. The life-cycle of this insect within the wheat-belt of the United States, a to Webster, is as follows: The winter is in the larval stage, and the short pupal step coming in May brings the emerging of adults at the tune when the fronal• is able as place her eggs on the plants where the young. on hatching, will make their way to the tender and succulent stem just above the upper By the time the straw has ripened the large have ceased to require food and pass through the pupal stage, the adults of this brood appear ing in July. Eggs are now deposited in volun teer wheat and grass, and, owing either to the retarding effects of meteorological indoesces or a diversity of food of the larvae or both. perhaps, the emerging of the adults is pro longed throughout a period extending from her August through September until late October. At this period the fall wheat offers a decidedly inviting plant to the female fly on which to place her eggs with a prospect of her progeny having an .abundant food supply. It is the lar va from eggs deposited during this period that winter over in the plants and give rise to the May-June generation of Ries. It is this last brood that is of more especial interest to the fanner, as it is very seldom that the pest does serious to grain except in fall and early spring. effect on the plant is this: is young plants the central spindle-shaped en folded leaf is killed, the detached portion turn ing first yellow and later brown, then shrivel ing up and dying, leaving the outer lower leaves uninjured. In Hessian-fly attacks this spindle shaped leaf is absorbed and does not appear at all in the young wheat in autumn, so that there need never be any confusion of the work of these two insects in fall wheat, and the effect on the full-grown straws is even more easily distinguishable. When attacked by the maggots of this species the fully grown straw withers at the upperjoint, and all that portion of the stem including the head, the sheath excepted, changes to a whitish color, the remainder of the plant.