258 FRUIT INSECTS 



The Mealy Plum Louse 

 Hyalopterus arundinis Fabricius 



This light green plant-louse of the plum is generally dis- 

 tributed throughout the country wherever its food-plant is 

 grown. It may be recognized by the three longitudinal darker 

 green stripes above and by the fine white powdery covering of 

 the body. 



The black shining eggs are deposited in the fall around the 

 buds on the smaller branches and hatch the following spring 

 soon after the opening of the leaves. The first generation is 

 composed entirely of wingless females known as stem-mothers. 

 They give birth to a large number of living young, all females, 

 which continue to reproduce in the same way for several genera- 

 tions. At first they are all wingless, but as the leaves become 

 crowded and the food supply scanty part of each brood acquires 

 wings and migrates to other plants until by the last of July prac- 

 tically all will have left th(^ trees, but in some instances they 

 have been known to remain on the plum throughout the season. 

 The alternate food-plants nvv., as far as known, various species 

 of grasses, particularly the Reed-grass (Phragmites phragmites 

 Linn). In September the return migrants appear on the trees 

 and give birth to winged males and wingless females. After 

 mating the latter deposit the winter eggs around the buds. 



Sometimes this plant-louse occurs in enormous numbers cover- 

 ing the entire under surface of the leaves, which turn yellowish 

 and drop without becoming noticeably curled. The loss of 

 foliage has been known to cause the falling of the fruit, but such 

 severe attacks are unusual. 



Treatment. 



In case the plant-lice appear in sufficient number as to threaten 

 injury to the crop it will pay to make a thorough spraying, 

 using kerosene emulsion, or one of the tobacco extracts to which 



