486 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 

 growers. ] 



DECIDUOUS FRUIT INSECTS. 



The European Fruit Scale. 



The brown apricot scale, or European fruit scale, as it is often termed, 

 is common throughout the deciduous fruit growing sections of Cali- 

 fornia. Its favorite hosts are the prune, plum, apricot, almond and 

 pear. With the advent of spring the scales, which winter over mostly 

 in the immature stages, develop into the adult form, and deposit large 

 number of eggs. The young emerge, settle on the leaves and begin to 

 suck out the sap. They excrete a sticky substance known as honeydew. 

 This honeydew on old infested trees covers the foliage, fruit and twigs, 

 and furnishes a medium for the black smut fungus in which to work, as 

 well as being a collector of dust. As a result the leaf functions are 

 impaired, and likewise the entire tree suffers. Honeydew-covered fruit 

 is unfit for use. 



S. W. Foster, formerly of the United States Bureau of Entomology, 

 states that it will be more effective to spray in the late winter, or the 

 early spring, after the winter rains have washed the summer's accumu- 

 lation of dust from the trees. He also states that the action of the 

 atmospheric conditions during the winter has a tendency to make the 

 insects more susceptible to the spray than is the case in the fall, and 

 advises spraying on clear days, when the trees are dry, and when the 

 temperature is above freezing. 



The formulse* for crude oil emulsion and distillate oil emulsion are 

 as follows: 



Crude Oil Emulsion. 



Water 175 gallons 



Liquid soap 3 gallons 



Crude oil 25 gallons 



Fill the spray tank with the water, add the liquid soap, agitate 

 thoroughly after which add the crude oil. 



If the liquid soap can not be obtained, use whale oil soap, 20 pounds 

 dissolved in 10 gallons of hot water, to which 3 pounds of caustic soda 

 is added. 



Distillate Emulsion. 



Distillate. 28° Baume 20 gallons 



Whale oil soap 30 pounds 



Water 12 gallons 



Dissolve the whale oil soap in hot water, add the distillate, agitate 

 thoroughly while the solution is warm. For use add 20 gallons of water 

 to each gallon of the above mixture. 



To destroy mites or lichens on fruit trees add 2 pounds of lye to the 

 formula of the stock solution. 



The prepared crude oil and distillate emulsions can be obtained from 

 several insecticide dealers throughout the state. 



♦Injurious and Beneficial Insects of California, by E. O. Bssig. 



