312 FRUIT INSECTS 



As the feeding quarters become crowded, winged forms (Fig. 

 270) are produced ; whether they merely fly to other cherry- 

 trees or establish summer colonies on other food-plants is un- 

 settled. In Colorado a few lice at least remain on the cherry 

 throughout the season. No alternate food-plant has been 

 found. Sexual forms are produced, and the winter eggs are 

 deposited in September and October. 



Treatment. 



This insect is not difficult to control by spraying with kero- 

 sene emulsion, whale-oil soap solution or tobacco extract, pro- 

 vided the work is done as soon as the lice appear and before 

 the leaves become curled. On nursery stock the lice attack 

 and curl the leaves on the tips of the young trees where it is 

 impossible to hit them with a spray. In such cases it has been 

 found practicable to dip the infested tips in a solution of whale- 

 oil soap, 1 pound in 7 gallons of water. The solution is carried 

 in a pail, and the tips of the young trees are carefully bent over 

 and held in the liquid long enough to wet all the lice. 



References 



Lintner, 5th Rept. N. Y. State Ent., pp. 253-257. 1889. 



Ohio Agr. Exp. Sta. Bull. Tech. Ser., Vol. I, No. 2, pp. 111-113. 1890. 



N. Y. (Geneva) Agr. Exp. Sta. Bull. 136, p. 598. 1897. 



Col. Agr. Exp. Sta. Bull. 133, pp. 42-44. 1908. 



The Cherry Scale or Forbes' Scale 

 Aspidiotus forbesi Johnson 



Discovered in Illinois in 1896, this scale insect has since been 

 found in widely separated localities throughout the United 

 States. Cherry trees, both wild and cultivated, seem to be 

 its favorite food-plants, the trunks, branches and sometimes 

 the leaves and fruits being attacked. It also occurs on apple, 

 apricot, pear, plum, quince and currant. Externally the 



