Insects and insecticidesA practical manual concerning noxious insects and the methods of preventing their injuries . re are usually not serious. Butin Europe a great deal has been accomplished inpreventing its injuries. According to. Dr. Riley themeans employed there consist in (1) methods whichavoid the necessity of direct treatment, comprising 114 INSECTS AFFECTING THE GRAPE. the use of American stocks and planting in sandysoils ; (2) the employment of insecticides (bisulphideof carbon, sulphocarbonate of potassium, and thekerosene emulsion); and (3) submersion. INJURING THE LEAVES. The Grap
Insects and insecticidesA practical manual concerning noxious insects and the methods of preventing their injuries . re are usually not serious. Butin Europe a great deal has been accomplished inpreventing its injuries. According to. Dr. Riley themeans employed there consist in (1) methods whichavoid the necessity of direct treatment, comprising 114 INSECTS AFFECTING THE GRAPE. the use of American stocks and planting in sandysoils ; (2) the employment of insecticides (bisulphideof carbon, sulphocarbonate of potassium, and thekerosene emulsion); and (3) submersion. INJURING THE LEAVES. The Grape-vine Flea-beetle. Graptodera is a small, steel-blue beetle (Fig. 52, d) thatis often very destructive to grape-vines. It hiber-nates as an adult. As soon in spring as the budsbegin to swell the beetles come forth and attack them. The injury atthis time isoften great,because theimmature leafand fl o w e rbuds are soeasily destroy-ed. The bee-tles continuefeeding forthree or fourweeks, duringthe latter partof the time de-positing smallorange-yelloweggs in clusters on the under sides of the Fig. 52. Grape-vine Flea-beetle: a, leaf infested bylarvte ; b, larva, magnified; c, cocoon; d, beetle,magnified. INJURING THE LEAVES. 115 They then die, and in a few days the eggs hatch intosmall, dark-colored larvae that feed upon the they grow older they gnaw irregular holes in theleaves, giving them and unsightly appear-ance (Fig. 52, a). When fully grown (three or fourweeks after hatching) they are about three-tenths ofan inch long, brown in color, with six legs, and fouror five black dots on the back of each ring or seg-ment of the body. The head is black, and there arenumerous hairs on the body. One is shown some-what magnified at b, Fig. 52. When fully grownthe larvae leave the vines, and, entering the soil, formearthen cocoons (c), within which they change topupae. A kw weeks later they again transform andemerge as perfect beetles. These als
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