Archive image from page 199 of The cultivated evergreens; a handbook. The cultivated evergreens; a handbook of the coniferous and most important broad-leaved evergreens planted for ornament in the United States and Canada cultivatedevergr00bail Year: 1923 ( 132 THE CULTIVATED EVERGREENS young lice crawl to the tender growth where they station themselves on the leaves which have already begun to show indications of the developing gall. The formation of the gall is apparently initiated by the feeding of the parent plant-louse. As the gall increases in size, the leaf tissue grows over the you
Archive image from page 199 of The cultivated evergreens; a handbook. The cultivated evergreens; a handbook of the coniferous and most important broad-leaved evergreens planted for ornament in the United States and Canada cultivatedevergr00bail Year: 1923 ( 132 THE CULTIVATED EVERGREENS young lice crawl to the tender growth where they station themselves on the leaves which have already begun to show indications of the developing gall. The formation of the gall is apparently initiated by the feeding of the parent plant-louse. As the gall increases in size, the leaf tissue grows over the young aphis which thus comes to occupy a closed cell. Within this retreat the aphid passes through four stages; the cell then opens and it escapes. This usually takes place in August. At the last molt the plant-louse acquires wings and then takes her position on a spruce leaf where she deposits a cluster of eggs, leaving her dead body over them as a protec- tion. On hatching, the young lice scatter over the nearby branches and attach themselves to the leaves and in crevices around the buds. It is in this condi- tion that the insect passes the winter. It is thought by some that the life history of the insect is not as simple as is indicated above but that there is a regular migration from spruce to larch and from larch to spruce. It is quite probable that a migration does take place when both kinds of trees are growing near each other. In cases in which larches are not present, the insect seems to be capable of breeding indefinitely on spruce. The spruce gall aphid can be controlled effectively on ornamental plants by thoroughly spraying with whale-oil soap—one pound in two gallons of water. The application should be made during the winter or in early spring before new growths start. A miscible oil—one part in twenty of 15. Spruce gall aphid on larch.
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Keywords: 1920, 1923, archive, bailey_l_h_liberty_hyde_1858_1954, book, bookauthor, bookdecade, bookpublisher, booksubject, bookyear, conifers, drawing, evergreens, historical, history, illustration, image, new_york_the_macmillan_company_london_macmillan_co, new_york_the_macmillan_company_london_macmillan_co_ltd_, page, picture, print, reference, vintage
