83 



suniinor of this year that this orchard has been under constant and 

 careful observation but one or two beetles of our native species have 

 appeared, and l)ut two of its larvte have been seen on the trees. Yet 

 within a stone's throw of this orchard is a tree on the grounds of the 

 Department infested with A. micj/lns, and on this tree, infested with 

 a native scale insect, the Chilocorus hivuhierus has established itself in 

 considerable numbers, probably several hundred larvae being present 

 on the tree. The history of this ladA^bird in the East, and as further 

 illustrated by the instance just mentioned, seems to indicate that it 

 prefers our native scale insects and has not yet fully accustomed itself 

 to the San Jose scale nor to the recently introduced Didspls pentagona. 

 It may take hold of these new scale insects in the course of years, but 

 it certainl}^ does not do so at present in a manner to be of any great 

 assistance in keeping them in check. '^' In Florida and California 

 especially on Citrus trees it is very abundant, as a rule, and an effi- 

 cient enemy of scale insects. The imported species feeds normally 

 and voraciously on the San Jose scale and Diaspis, and, if it survives 

 our climate and can be established, we may hope that it will accom- 

 plish for us some, at least, of the good results which it was seen to 

 achieve generally for China and Japan. 



In the matter of climate, it may be said that the region in which it 

 occured in China and Japan will duplicate nearl}^ enough the eastern 

 United States or California. We have about the same summer and 

 winter temperature and similar general conditions of rainfall and other 

 climatic features, so that from this point of view there seems to be no 

 reason why the imported ladybird should not do well. 



That this ladybird or any other parasitic or predaceous insect will 

 ever completely subdue the San Jose scale in the United States is very 

 problematical, and there is very little doubt but that in future, as in 

 the past, to free an orchard from this scale pest it will be necessary 

 to take the direct and active means noAv being emploj^ed, such as the 

 use of oil, or the lime, sulphur, and salt wash, or other remedies 

 which experience shall demonstrate to be effective. What parasites 

 or predaceous enemies may do is to keep this scale in check so that it 

 will not be so generally abundant and destructive, and especially to 

 keep it down in the thousands of small orchards and gardens where 

 direct spraying operations would not often l)e undertaken by the 

 owners. 



In particular districts it may even put a complete check on the San 

 Jose scale for one or several years. That this is possible is indicated 



« Toward the end of July some 26 specimens of the native Chilocurns bivulnerus 

 v/ere caged over a San Jose scale-infested pear tree to make comparative studies of 

 the life history and habits of the species. Unfortunately, however, all of these 

 beetles perished, without our securing either eggs or larva*. This rather astonishing 

 and unexpected outcome seemed to be due to a distinct disinclination on the part of 

 these beetles to eat the San Jose scale except in the most sparing manner. 



