392 



THE MONTHLY BULLETIN. 



CALENDAR OF INSECT PESTS AND 

 PLANT DISEASES. 



By E. J. VoSLER. 



[Under the above heading the author aims to give brief, popular descriptions and 

 methods of controlling insect pests and plant diseases as nearly as possible just prior 

 to or at the time when the suggestions given should be carried into effect by the 

 yrowers.] 



THE BLACK SCALE. 



The black scale is the most important insect enemy of the citrus 

 tree. It is generally distributed in all the citrus growing sections 

 south of Tehachapi, and while it is not so much of a pest in the citrus 



Fig. SO.^ — Black scale, Saissetia olew, immature and full-grown, on oleander. (After 

 Essig, Injurious and Beneficial Insects of California, State Comm. Hort.) 



sections of the San Joaquin and Sacramento valleys, it occasionally 

 causes much damage. It is most destructive in the Coast comities, 

 no doubt on account of the humidity . 



The adult scales are black, with a distinct "H" on the back, and 

 are from ^ to i inch in diameter. They lay their eggs mostly during 



