. Ontario Sessional Papers, 1919, . of Injuky. The psvlla causes injury by extracting -with its sucking mouth-parts the sapfrom the leaves, leaf petioles, fruit stems, and tender wood on which it badly infested trees, the continual sapping of the life juices by myriads ofinsects robs the tree of vitality, dwarfs the fruit, produces brown, dead areas onthe leaves (Fig. 1-t) aud, in extreme cases, causes the foliage to drop seriously weakened by this pest are especially susceptible to winter injuryand in a hard winter like that of lOlT-lS readily succumb to lo
. Ontario Sessional Papers, 1919, . of Injuky. The psvlla causes injury by extracting -with its sucking mouth-parts the sapfrom the leaves, leaf petioles, fruit stems, and tender wood on which it badly infested trees, the continual sapping of the life juices by myriads ofinsects robs the tree of vitality, dwarfs the fruit, produces brown, dead areas onthe leaves (Fig. 1-t) aud, in extreme cases, causes the foliage to drop seriously weakened by this pest are especially susceptible to winter injuryand in a hard winter like that of lOlT-lS readily succumb to low temperatures. Large quantities of a sweet sticky liquid called honey-dew are excreted by thepsyllas. and on attacked trees the foliage, fruit, twigs and branches may be coveredwith this sticky material and with a sooty fungus which grows in it. (Fig. 15).This coating of honeydew and sooty fungus not only makes the trees and fruitvery unsightly but it is very probable that it is also detrimental to the physiologicalfunctions of the
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