[Fruit culture] . sylla is an active four-winged insect, measiu-ingabout To inch in length. It has been compared to a miniature seventeen-year adult psylla isshown in Fig. 22 (a).The winter adiilts ap-pear early in springand deposit eggs forthe first brood in pro-tected places in thebark. The eggs hatchin a few days, and theyoung larvas, ornymphs, one of whichis shown in Fig. 22 (b), at once begin to suck the juices fromthe young leaves and twigs. A favorite place for the younglarvas is in the axils of the leaves at the base of the fruitstems. Two or three da^^s after hatching, the l
[Fruit culture] . sylla is an active four-winged insect, measiu-ingabout To inch in length. It has been compared to a miniature seventeen-year adult psylla isshown in Fig. 22 (a).The winter adiilts ap-pear early in springand deposit eggs forthe first brood in pro-tected places in thebark. The eggs hatchin a few days, and theyoung larvas, ornymphs, one of whichis shown in Fig. 22 (b), at once begin to suck the juices fromthe young leaves and twigs. A favorite place for the younglarvas is in the axils of the leaves at the base of the fruitstems. Two or three da^^s after hatching, the larvas coverthemselves with honey dew, which finally becomes so abun-dant that it besmears the leaves and fruit. The extent of theinjury done in this way varies, of course, with the number ofthe larvas. When the larvas are very nimierous they take somuch nourishment from the trees that the new growth isseriously checked. The whole tree assumes a stunted, un-healthy appearance. As a result, the fruit crop is greatly. Fig. 22 § 8 PEAR CULTURE 35 lessened and in some cases the trees are killed. Trees weak-ened by the psylla often fail to survive the winter. The following control measures for the psylla have beenrecommended by the New York Agricultural ExperimentStation: 1. Practice clean culture in the orchard so that there will beno accumulations of weeds to serve as wintering places. 2. Remove all rough bark in order to prevent the adultsfrom wintering on the trees and to render them more exposedto spraying mixtures. Bark is most easily detached imme-diately following a wet period. Care should be exercised notto cut into live tissue. 3. Spray thoroughly to kill the adults with Blackleaf 40, acommercial nicotine preparation, using f pint to 100 gallons ofwater, and 3 pounds of soap; the spraying should be donepreferably during a warm period in November or December,or during March or early April. Select a day when the mixturewill not freeze on the trees. For spring spraying, some
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Keywords: ., bookcentury1900, bookdecad, booksubjectfruitculture, bookyear1912
