56 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



been collected in sweepings in the chaparral belt at an elevation of 

 3000 feet. So far there have been no reports of its attacking olive 

 trees in Fresno County. On July 9, 1916, the writer received a small 

 piece of olive bark from a grower at Bakersfield, Kern County, show- 

 ing small exit holes exactly like those made by the insect in question, 

 with the statement that the insect causing the injury had badly at- 

 tacked the young olive trees with the result that one was already 

 dying. The possibilities of its being the same thing are very strong, 

 though no opportunity has been afforded to make a personal investi- 

 gation. 



As in the case of other orchard bark-beetles, the first essential in 

 avoiding attacks is to maintain a healthy condition of all the trees 

 and to prevent sunburn and injuries which lessen their vitality and 

 furnish the proper conditions for the entrance of the beetles. The 

 immediate burning of all prunings is also important, to eliminate 

 possible breeding places around the orchards. After an orchard has 

 become infested, the only effective step is to cut out and burn all 

 infested limbs or trees as soon as discovered, to avoid spreading and 

 continued attacks. 



The small hymenopterous parasite 5 which attacks the immature 

 stages with'in the burrows is not likely to be of much consequence in 

 controlling the beetle. 



II. INSECTS OF MINOR IMPORTANCE TO OLIVE TREES IN CALIFORNIA 



Of the following insects, it is not likely that any will prove of 

 real economic importance, but they are included because they are 

 sometimes found infesting the olive trees and excite the suspicion of 

 the orchardists. 



1. The citrus thrips, Scirtothrips citri (Moulton). Taken in the 

 flowers of olive trees in the San Joaquin Valley. 6 



2. The bean thrips, Heliothrips fasciatus Pergande. Reported as 

 seriously infesting the fruit of olives in San Joaquin County in 1915. 7 



3. The net-winged cicada, Platypedia areolata Uhler. Sometimes 

 punctures the small limbs of the olive to insert its eggs. The punc- 

 tures cause the twigs to become distorted or to break. The distribu- 

 tion is general throughout the state. 



5 The parasite has been determined by Mr. Kohwer as Eophylus, probably 

 schwarzi Kohwer, through the kindness of Mr. Harry S. Smith, superintendent 

 of the State Insectary. 



e Jones, P. E. & Horton, J. K., Bull. no. 99, pt. 1, p. 3, Bur. Ent., U. S. Dept. 

 Agr., 1911. 



7 Smith, H. S., Mthly. Bull. Cal. Hort. Com., vol. IV, p. 574, 1915. 



