. Manual of fruit insects. FiG. 388. — Grape root-worm pupa in its earthen cell. 448 FRUIT INSECTS. YiG, 389. — This grapevine was killed by the grubs. All of the fine feedingroots were eaten off and the main roots scarred or pitted by the grubs. GEAPE INSECTS 449 wards the last of June and in July. Normally the life-cycleis completed in one year, but under adverse conditions, such ascompact clay soil or an insufficient supply of food, the larvaldevelopment may be so retarded that they require a secondseason in which to reach maturity. In the latter case they gointo hibernation early, in Augus
. Manual of fruit insects. FiG. 388. — Grape root-worm pupa in its earthen cell. 448 FRUIT INSECTS. YiG, 389. — This grapevine was killed by the grubs. All of the fine feedingroots were eaten off and the main roots scarred or pitted by the grubs. GEAPE INSECTS 449 wards the last of June and in July. Normally the life-cycleis completed in one year, but under adverse conditions, such ascompact clay soil or an insufficient supply of food, the larvaldevelopment may be so retarded that they require a secondseason in which to reach maturity. In the latter case they gointo hibernation early, in August of the second year, and prob-ably give rise to the earliest beetles the following spring. Treatment. As the grape root-worm beetles feed extensively on the uppersurface of the leaves before beginning to lay their eggs, anexcellent opportunity is presented to destroy them with anarsenical spray. Arsenate of lead, 6 pounds in 100 gallons ofwater, is the poison now used most extensively for this purpose,replacing Paris green and arsenite of lime because of its greateradhesiveness and owing to
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbenefic, bookyear1915
