17 



It is clear, therefore, that if not kept under control there is no more destructive 

 enemy to fruit trees than the San Jose Scale. 



Natural Enemies. — Many of our scale insects are to a very considerable extent 

 kept in check by predaceous enemies and parasites, but this is not true of the San 

 Jose Scale. Its chief enemies are as follows: — (1) A very tiny, glossy-black lady- 

 bird beetle, Microweisea (Pentilia), misella and its brown larvae. (See Fig. 9.) 

 A considerable number of these were found on most of the trees examined, but 

 they were never numerous enough anywhere to control the scale even on a single 

 branch. (2) A much larger black ladybird beetle with two red spots on its back, 

 Chiloconis hivulnerus. This is a common insect in Ontario, but was very rarely 

 found feeding on San Jose Scale. (3) Four- winged hymenopterous parasites (see 

 Fig. 10.) Two species of these Aphelinus mytilaspidis and Aphelinus fiLScipennis 

 were reared a few years ago by Mr. Alfred Eastham, a graduate of the Agricultural 

 College, but a careful examination of several orchards showed very few scales with 

 little circular holes in them indicating that a parasite of this nature had emerged. 

 (4) A large red mite that I have not yet had a chance to get identified. (5) A 



Fig. 9. The Pitiful Ladybird Beetle and its larva 

 (Microioeisea misella), both much enlarged. 

 The small lines show the natural size (redrawn 

 from Marlatt). 



fungus disease. This seems to be very rare. I have not myself seen it, but the late 

 Dr. Fletcher reported it from the Niagara district. 



From my own observations I think that all these enemies combined do not kill 

 more than one scale out of one thousand. This, however, is not true of all parts 

 of North America, for in some places disease or parasites or both are very helpful. 

 In October Prof. Surface, of Pennsylvania, replying to a letter of mine said that 

 the four-winged parasites there were becoming very abundant and doing a great 

 deal to control the scale. He reported that there were many different species at 

 work. It is my intention next year to bring in a good supply of parasitized material 

 from Pennsylvania and try to establish these friends in our worst infested dis- 

 tricts. Whether they will increase rapidly in our climate and become of mucli 

 assistance is impossible to tell. 



MEANS OF CONTROL, 



In controlling San Jose Scale it is absolutely necessary to depend upon thor- 

 ough spraying of infested orchards, but spraying is simplified and made less costly 

 by certain preliminary steps. It should be borne in mind in treating neglected 



