Puant Lice INJURING FOLIAGE AND FRUIT OF THE APPLE (723 
both species have spread to a considerable extent in the orchard sections 
of that and other Western States. P. A. Lehenbauer, Botanist of the 
University of Nevada, informs the writer that neither species is reported 
from Nevada, tho he thinks they may occur in some localities. It may 
be added that Aphis sorbi is not reported as being present in Nevada. 
There is a remarkable parallelism between the introduction and spread 
of Plantago lanceolata and the spread and increasing destructiveness of 
Aphis sorbi. It has already been pointed out by the writer that this 
plant not only is the preferred, but seems to be the essential, summer 
host plant for this aphid. This statement is supported not only by 
experimental work but also by the study of the spread of the species. 
Had Plantago major been as favorable a summer host plant, the rosy 
aphis should have become abundant at an earlier date, as this plant 
was widely distributed thruout the country in advance of Plantago lanceo- 
lata. Had Plantago major var aszatica, a native thin-leaved variety found 
in Canada and the northern United States, been a favorable summer 
host plant, earlier outbreaks thruout the orchard areas of eastern Canada 
and the northeastern United States would have been expected. This 
is certainly not the case, as this aphis is first recorded as doing serious 
damage in the eastern United States and gradually working westward, 
northward, and southward in close relation with the spread of Plantago 
lanceolata. As has already been pointed out, neither species of plantain 
is abundant thruout the Rocky Mountain region. It is also well known 
that Aphis sorbi is not abundant nor seriously injurious in that region, 
except in certain restricted orchard sections where the narrow-leaved 
plantain has become well established. A very interesting situation is 
reported to the writer from British Columbia. In the coastal area Aphis 
sorbt has been abundant and destructive for a number of years, while 
in the interior valleys, where many of the larger orchards are found, this 
plant louse has appeared only in the last few years. Plantago lanceolata 
is reported by Macoun”! as having been abundant in the coastal area since 
1890, but it did not spread to the interior valleys until within the last 
few years. In consequence outbreaks of Aphis sorbi are now being reported 
from some of the larger orchard sections in the interior. 
2 Macoun, John. Catalogue of Canadian plants. Part II—Gamopetalae, p. 193-394. Canada Geol 
and Nat. Hist. Survey. 1884. 
