NOTES FROM THE BIOLOGICAL DEPARTMENT OF THE 

 ONTARIO AGRICULTURAL COLLEGE— III. 



THE ORIGINAL HOME OF THE SAN JOSE SCALE. 



>ANY attempts have been made in 

 recent years to fix the original 

 =;;~-^ home of the San Jose Scale. Cal- 

 ifornia, China and Japan, each in turn, have 

 been honored in this connection, but no 

 evidence of a definite trustworthy nature has 

 been produced to determine for a certainty 

 the nativity of the Scale. 



The real object of all such investigations 

 was to ascertain what are the natural enemies 

 which kept the Scale in check in its native 

 home, for it must be evjdent that some influ- 

 ence must be at work there, holding in check 

 this most prolific insect, which has spread so 

 rapidly in America when free from its usual 

 enemies. Many are of the opinion that if 

 these enemies could be discovered it might 

 be possible to import them, and propagate 

 them among the scale infested orchards of 

 this country. 



While it is true that very few successful 

 experiments in the importation of the 

 enemies of injurious insects have been carried 

 out, yet there is no reason why we should 

 become discouraged in the case of the San 

 Jose Scale. Much has been learned by the 

 failures regarding the conditions which are 

 necessary for the successful importation of 

 predaceous insects. In the first place, the 

 climate of the native country of the predace- 

 ous or parasitic forms should not diff'er very 

 much from that of the country to which they 

 are taken ; and in the second place, the 

 parasitic forms should find insects in their 

 new country with which they are already 

 acquainted. To induce foreign parasites, 

 etc., to prey upon insects altogether un- 

 familiar to them would require an adjustment 

 of conditions which is usually only possible 

 in nature' after a long period of time. The 

 success of the TW^/za introduction into Cal- 



ifornia in checking the Icerya or Cottony 

 Cushion Scale resulted from the fact that the 

 \'edalia found the identical species of scale 

 with which it was quite familiar in Australia. 



Last summer, Mr. Krwana, a Japanese 

 student of Entomology in Stanford Univer- 

 sity, California, returned to Japan for the 

 purpose of collecting and studying the scale 

 insects of his native land. He found the 

 San Jose Scale widely distributed in most of 

 the islands, in the interior as well as along 

 the coast. He observed, moreover, that it 

 was doing comparatively little injury in the 

 orchards, where it was found on plum, pear, 

 apple, Japanese quince, currant and willow. 



Several enemies of the scale were quite 

 common, among which were three species 

 of lady-beetles, a chalcid fly, and the larva 

 of a moth ; and it is the opinion of Mr, 

 Krwana that these are the agents which 

 keep the scale in check. Curiously enough 

 the scale was not found on any wild, uncul- 

 tivated tree or shrub, an observation which 

 may be explained by the fact that orchard 

 cultivation has been in existence in Japan for 

 many centuries ; and that the pest has taken 

 more kindly to the cultivated trees and shrubs 

 than to the uncultivated wild forms. Sub- 

 sequent examinations, however, may discover 

 the scale on the wild trees. 



It is to be hoped that experiments in the 

 importation of these enemies of the scale 

 may be tried, and that another brilliant 

 success may be chronicled in the annals of 

 economic entomology. 



SPRAYING, 



Experience has shovn very conclusively 

 that the great secret of success in spraying 

 is spraying early, spraying several times 

 during the season, spraying every year, and 

 spraying intelligently. When we know that 



