33 



Thelia acuminata Fabr. Sap feeder. 

 1892, Coding, Insect Life, 5:93. 



Vandusea arquata Say. Feeding on sap of black locust. 

 1904, Reported by Prof. H. Osborn. 



Family ^Coccidae. 



Aspidiotus perniciosus Comst. The San Jose Scale. This scale 

 insect, although of quite recent introduction, has a wide range of food 

 plants, feeding upon a large number of woody plants, among which is the 

 ■black locust. While the writer has observed this pest on locust trees and 

 sprouts at several points in the state, no instance is known where it had 

 done serious injury to this host. This tree seems to be one of the many 

 species upon which the San Jose scale is able to live and. even to repro- 

 duce itself, and yet never become numerous enough to inflict serious dam- 

 age. It is only on those locust trees and sprouts which are growing near 

 "badly infested fruit trees that this scale is likely to be found. It is more 

 commonly found on the locusts along ravines and on vacant lots in cities, 

 ■or in artificial plantations. 



NATURAL ENEMIES. 



This pest is believed to be a native of northern China, and as it is 

 ■not serious in that country an effort was made to find its natural enemies. 

 The explorations of Mr. C. L. Marlatt, of the United States Bureau of 

 Entomology, resulted in the finding of a lady beetle {Chilocorus similis) 

 "which feeds upon the San Jose scale. This beetle was imported into the 

 •United States, but has not proven a success. A colony was established 

 in Ohio by this Division, but became extinct within a year. 



Two of our common lady beetles feed quite freely upon this scale 

 insect, both in their adult and larval states : Pentilia misella and Chilo- 

 corus bivulnerus. Collops qtiadrimcDculatus has been observed feeding 

 ■upon the same host, as has also Scymwus lophanthae. Two chalcids have 

 been reared frorn this host : Aphelinus fuscepennis How. and A. mytila- 

 spidis (Le B.). Valuable as is the work of these natural enemies, none . 

 of them are present in sufficient numbers to be of any importance in the 

 control of this pest. Their efforts must in all cases be supplemented by 

 -direct measures. 



A large number of contact insecticides have been tried upon this 

 insect, of which the lime and sulfur wash has given the best satisfaction 

 -under orchard and park conditions. With small trees, as in nursery 

 stock that may be dug and packed into small pace, the fumigation method 

 IS the best. 



