346 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 5 



SOME INSECT PESTS OF THE CALIFORNIA LIVE OAKS 



By R. W. DoANE, Stanford University 



(As this is a preliminary report on the study of the Oak pests, only 

 an abstract of the paper is given here.) 



During the past year the oaks in the Santa Clara Valley have been 

 having a particularly serious time. The live oaks especially have suf- 

 fered from the attacks of leaf-miners. In addition to the leaf-miners, 

 the twig-girdlers have been doing a great deal of damage and the 

 carpenter worms, which heretofore have been found only occasionally 

 in old weakened trees, have this year developed into verj' important 

 pests, killing some trees and very seriously injuring many more. 



The Oak Tree Moth. The first serious outbreak of Phryganidia 

 in the Santa Clara Valley occurred in the fall of 1894 and the spring 

 of 1895 when, entirely without warning, the larvae appeared in astound- 

 ing numbers and completely stripped all of the oak trees in the vicinity 

 of Stanford University, appearing in less number at the same time in 

 other parts of the valley. 



Few parasites were noted in the first fall brood of the larvae; the 

 following over-wintering brood were found to be rather badlj^ para- 

 sitized; and the larvae and pupa of the next fall brood, the third of 

 the outbreak, were so badly parasitized that but few reached the adult 

 condition and the parasites than remained in control a number of 

 years. 



During the spring and summer of 1908 nearly all the trees in the 

 vicinity of the University were again defoliated. In June 935 larvae 

 and pupa were collected from a mass on an oak tree ; 228 of these were 

 parasitized by Pimpla hehrendsii Cresson, 704 were killed by a bac- 

 terial disease and three adults issued. In October of the same year 

 1170 were collected in the same locality; 83 per cent were parasitized, 

 6 per cent were killed by a bacterial disease, 4 per cent reached the 

 adult condition and 7 per cent died from undetermined causes. 



Tne larvae attacked by the bacterial disease showed to a remarkable 

 degree the tendency to mass together. 



Tussock Moth. Instances almost as remarkable might be cited to 

 show how the tussock moth is controlled by its parasites, principally 

 the Tachina flies, although the small hymenopterous jjarasites and the 

 Dermestes beetles also do important work. 



The last serious outbreak of the tussock moth larvae occurred 

 in the spring of 1907. 



Leaf-Miners. We have at least three species of leaf-miners infesting 



