. Manual of fruit insects. y infested trees take on a sicklyappearance early in the season, the leavesturn brownish or black, dry up and fallin midsummer; the fruit remains smalland much of it falls prematurely. Someorchards give the impression of havingbeen swept by fire, and owing to theirweakened condition are especially liableto winter killing. The adults hibernate on the trunksin crevices and under flakes of bark, andwhen very abundant they may collect Fig. 201-The pear psylla, ^^^^j. jg^^^^g ^^^i ^^^^^l on the ground,adult ( X 20). ^ The adult psylla has beeti aptly likenedto a diminutiv
. Manual of fruit insects. y infested trees take on a sicklyappearance early in the season, the leavesturn brownish or black, dry up and fallin midsummer; the fruit remains smalland much of it falls prematurely. Someorchards give the impression of havingbeen swept by fire, and owing to theirweakened condition are especially liableto winter killing. The adults hibernate on the trunksin crevices and under flakes of bark, andwhen very abundant they may collect Fig. 201-The pear psylla, ^^^^j. jg^^^^g ^^^i ^^^^^l on the ground,adult ( X 20). ^ The adult psylla has beeti aptly likenedto a diminutive cicada or dog-day harvest-fly (Fig. 201);they are about ^V i^^ch in length, dark reddish-brown in color,with the abdomen banded with black. When at rest the twopairs of large, nearly transparent wings slope roof-like overthe sides of the body. With the first warm days of spring the adults emerge fromtheir winter quarters and egg-laying begins in a few yellowish-orange eggs, about -g\ inch in length are deposited. PEAR AND QUINCE INSECTS 219 in the creases of the bark, in old leaf scars and about the baseof the terminal buds. They are elongate pyriform in shapeand have a smooth shining surface. A short stalk at the largerend attaches the egg to the bark and a long thread-like processprojects from the smaller end. A large proportion of the eggsis laid before the buds open. They hatch in 11 to 30 days,depending on the temperature. Most of the eggs have hatched by the time the petals recently hatched nymphs are of a translucent yellow colorand are hardly visible to the unaidedeye, being scarcely g^ inch in migrate at once to the axils of theleaf petioles and stems of the formingfruit, and when these places becomecrowded they will scatter out on theunderside of the leaves and on thepetioles. They are provided with suck-ing mouth parts and feed exclusively onthe sap. The larger part of the saptaken into the body is elaborated intoa sweet, sticky substa
Size: 1115px × 2240px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectbenefic, bookyear1915
