Insect pests of farm, garden and orchard . ls 35° and 45° westward to the 100thmeridian, on the Pacific coast, in Canada, and in many other partsof the world where wheat is grown. Not infrequently it destroys25 to 50 per cent of the whole crop in some localities, and it hasbeen estimated that 10 per cent of the crop of the whole countryis lost from its ravages. Life History.—The adult flies are little dark-colored gnats about* Mayeiiola destructor Say. Family Cecidomyidos, 124 INSECT PESTS OF FARM, GARDEN AND ORCHARD one-tenth inch long, so small as to commonly escape female l
Insect pests of farm, garden and orchard . ls 35° and 45° westward to the 100thmeridian, on the Pacific coast, in Canada, and in many other partsof the world where wheat is grown. Not infrequently it destroys25 to 50 per cent of the whole crop in some localities, and it hasbeen estimated that 10 per cent of the crop of the whole countryis lost from its ravages. Life History.—The adult flies are little dark-colored gnats about* Mayeiiola destructor Say. Family Cecidomyidos, 124 INSECT PESTS OF FARM, GARDEN AND ORCHARD one-tenth inch long, so small as to commonly escape female lays 100 to 150 minute reddish eggs, one-fifteenthinch long, placing them in irregular rows of from three to five ormore, usually upon the upper surface of the leaves. In a few dajsthese hatch into small, reddish maggots, which soon turn white,are cylindrical, about twice as long as broad and have no true heador legs. The fall brood of maggots burrow beneath the sheaf ofthe leaf and its base, causing a slight enlargment at the point of. Fig. 90.—^The Hessian fly {Mayetiola destructor): a, female fly; b, flaxseedstage or pupa; c, larva; d, head and breast-bone of same; e, pupa;/, puparium; g, infested wheat-stem showing emergence of pupae andadults. (After Marlatt,, U. S. Dept. Agr.) attack; but in the spring they usually stop at one of the lowerjoints, in both instances becoming fixed in the plant, absorbingits sap and destroying the tissues. The first indications of thework of the maggots on winter wheat in the fall are the tendencyof the plants to stool out, the dark color of the leaves, and theabsence of the central stems. Later man} of the plants yellowand die. The spring maggots attack the laterals, or tillers, whichhave escaped the previous brood, so weakening them that the INSECTS INJURIOUS TO SMALL GRAINS 125 stems break and fall before ripening and cannot be readily har-vested. A])oiit four weeks after hatching the maggots are full grown,and are gieenish-white and
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