climates. Again between Guelph and the Niagara district the difference' in climate 

 is sufficient to lessen the length of the breeding season by about a month, so that 

 this factor along with the greatly lessened number of days of optimum temperature 

 and the other facts mentioned above all lead to the hope that most of the parts not 

 infested to-day in Ontario will remain free. Time alone, however, will tell whether 

 this hope will be verified, and until we are certain the best course is as I have said 

 above, to " Take no chances." 



PLANTS ATTACKED BY SAN JOSE SCALE. 



We have found the scale attacking the following orchartl trees and shrubs 

 severely: Apple, crab, pear, plum {both European and Japanese), peacli, sweet 

 cherry, red currant and black currant. It very seldom attacks sour cherry; in fact 

 we have never found it on any of the sour cherry varieties. Kieffer pears, though 

 occasionally attacked, are seldom much infested even when near other trees badly 

 attacked. Quince, apricot and gooseberry in our experience are not commonly or 

 severely attacked, though it is very probable that we may find exceptions in the 

 future, as some writers include these among the severely or commonly infested 

 plants. Of apple trees, the Spy, though by no means immune, seems usually to be 

 less severely attacked than most other varieties. 



In addition to the above plants Ave have found the scale on the following orna- 

 mentals or forest trees and shrubs: Mountain ash, haivthorn, Japanese quince, 

 Japanese flowering crab, rose, wild red cherry or pin cherry, American elm, 

 European elm, dogwood (Cornus alternifolia and C. siberica), willow {Salix vitel- 

 lina), poplar {species not certain, but probably Carolina poplar {Populus deltoides), 

 juneberry, lilac, sumach (Rhus typhina), Japanese ivalnut and honey locust 

 (Gleditsia triacanthos) . The first four of these plants are often very severely 

 attacked, and sometimes killed. The elms, when small, may be destroyed ; but once 

 they have become fifteen feet or more in height the scale does not seem to be able 

 to kill them, though it may cause some of the smaller branches to die. 



Dr. W. E. Britton* in his carefully compiled list of plants commonly attacked 

 by the scale includes the following additional Ontario trees and shrubs : Chokecherry, 

 Lombardy poplar, flowering currant (Ribes aureum), osage orange and several 

 species of willow. 



San Jose Scale may also be found in very limited numbers on almost any tree 

 that is close beside or beneath badly infested trees; for instance I have found it on 

 the following young trees : maples of several kinds, catalpa, birch, oak, tulip, bass- 

 wood and horse chestnut, situated alongside very badly infested pears and plums, 

 but it is doubtful whether it winters on such trees. 



The above lists of ornamental and forest trees and shrubs might give the impres- 

 sion that our forests are likely to harbor the scale in great numbers and so become 

 a dangerous source of infestation, but this does not seem to be the case. We find 

 that scale-infested trees are usually situated in the orchard or else along the road- 

 side, in fence corners or on lawns, and, while susceptible species of the outer trees 

 of a forest bordering on an infested orchard may be attacked, there is usually little 

 danger from the forest trees as a whole. 



-^ ■ — . . ■ » 



♦Report of the Connecticut Agricultural Experimental Station, 1903, Part II., second 

 report of the Entomologist, pp. 132-138. 



