. Manual of fruit insects. ce between the sexes until it is necessary to molt again,when it is seen that a winged insect, the male, is being developedunder some of the scales. This second cast skin of the femaleis added to the scale-covering; a few days later the fully de-veloped, delicate, two-winged male insect without mouth parts 174 FRUIT INSECTS emerges and seeks its mate. The yellowish females continueto increase in size, remain grub-like in form and secrete the large,brown portion of the scale, becoming full grown in August orearly September in the North. Egg-laying soon begins, thebody
. Manual of fruit insects. ce between the sexes until it is necessary to molt again,when it is seen that a winged insect, the male, is being developedunder some of the scales. This second cast skin of the femaleis added to the scale-covering; a few days later the fully de-veloped, delicate, two-winged male insect without mouth parts 174 FRUIT INSECTS emerges and seeks its mate. The yellowish females continueto increase in size, remain grub-like in form and secrete the large,brown portion of the scale, becoming full grown in August orearly September in the North. Egg-laying soon begins, thebody of the mother gradually shrinking into the smaller end ofthe scale, and the 30 to 100 eggs occupying most of the spacebeneath the scale. In New York, egg-laying sometimes beginsearly in August, but in 1907 it was delayed until October insome localities. There is but a single generation of the oyster-shell scale in the North, but in southern New Jersey and Penn-sylvania and farther south there are two generations Fig. 172. — Old and recently set oyster-shell scales on willow. This oyster-shell scale has a wide range of food-plants. Itoften nearly covers the bark of the larger branches (Fig. 170),and even the twigs of apple and pear trees, and is often equally asnumerous on lilac bushes, willow, mountain ash and poplartrees. It may also attack quince, plum, raspberry, currant andfig among the fruits, and includes more than twenty-five shadetrees and shrubs in its list of host-plants. It infests trees of allsizes and ages, often killing young trees and severely injuringlarge ones. Orchards that are kept in a thrifty growing conditionand the trees not crowded rarely suffer serious injury from thisscale, but we have seen the lower limbs especially, and sometimesthe whole of large trees, killed by the insect where the trees werecrowded and neglected. Usually the bark of the tree only is APPLE INSECTS 175
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbenefic, bookyear1915
