.548 CALIFORNIA FRUITS: HOW TO GROW THEM 



Horticulture, at Sacramento ; and of the Bureau of Entomology 

 the United States Department of Agriculture, at Washington, 

 most useful addition to the horticulturist's library will be found in 

 Kellogg's "American Insects," published by Henry Holt and Com- 

 pany, New York. This excellent work of Professor Vernon Kel- 

 logg, of Stanford University, is particularly valuable because of its 

 California observations and point of view. Furthermore as the 

 study of the pests and the invention of means for their destruc- 

 tion are continually progressing one can only keep himself up 

 to date and enable himself to profit by improvements, by diligent 

 reading of California periodicals devoted to practical horticulture. 



CLASSES OF INSECTS 



In order to arrange injurious insects in classes in a popular 

 way, the grouping here will be based upon the character of the 

 work they do. This arrangement has been followed by other writ- 

 ers and is perhaps better than attempting to group the insects which 

 prey upon any single tree or plant, because injurious insects seldom 

 restrict themselves to a single food plant. Therefore the group- 

 ing will be as follows : 



(1) Insects destroying foliage; 



.(2) Insects upon the bark or upon the surface of leaf and fruit; 



(3) Insects boring into the twig, stem or root ; 



(4) Insects boring into the pulp of fruits. 



INSECTS DESTROYING FOLIAGE 



Cut Worms and Army Worms.* These are the larvae of Noc- 

 tuid moths, which often become abundant over limited areas and 

 do much damage to trees and plants. Cut worms and Army worms 

 are terms applied to the same insects in California. In ordinary 

 years they are not present in sufficient numbers to cause much con- 

 cern, and in such years they are known simply as cut worms. When 

 all conditions are favorable, however, certain species develop in 

 enormous numbers and having exhausted the food supply where 

 they breed, they begin to migrate or march, commonly in a definite 

 direction, as an army in search of new food. When they thus ap- 

 pear in such large numbers and take on the migrating habit they 

 are called army worms. 



Some of the caterpillars have the habit of climbing up vines and 

 trees and eating off the buds in the early spring* These are called 

 climbing cut worms. Others remain at or near the surface of the 



'Adapted from Bulletin 192, Agr. Exp. Station, University California, Berkeley. 



