Puant Lice InsjurinG FOLIAGE AND FRUIT OF THE APPLE 721 
being that of Britton (1910) and more recently those of Brittain (1915 b) 
and Baker and Turner (1916 b). 
Altho this plant louse has been present for some time over a large 
section of the United States, it did not assume the status of an important 
apple pest until late in the nineteenth century. This is readily under- 
stood when it is considered that this species, in order to thrive, must have 
near at hand an abundance of its summer host plants, the narrow-leaved 
and broad-leaved plantains (Plantago lanceolata L. and P. major L.). 
From the writer’s rearing experiments and field observations, it may be 
concluded that the narrow-leaved plantain (P. lanceolata) is the preferred 
host plant; in fact it appears to be essential, at least at Ithaca, to the 
continued reproduction of the species during the summer. Breeding experi- 
ments on broad-leaved plantains were never successful for more than two 
or three generations, the line dying off, sometimes very quickly. This 
agrees with the results of Baker and Turner (1916 b), altho Ross (1915) and 
Brittain (1916) report very successful breeding experiments on P. major. 
Introduction and spread of summer host plants 
The two species of plantains Plantago major L. and P. lanceolata L. 
are importations from Europe. P. major appeared early, in all proba- 
bility with the first permanent settlers in New England. Josselyn* 
records it as present in New England and following closely the habitats 
of the white settlers. So closely was it associated with the white man’s 
coming that the Indians named it Englishman’s foot, as tho it was 
produced by his treading. Bigelow’ reports it as a common roadside 
weed in New England. Oakes® lists it as common about the houses 
and roadsides of Vermont. Since his time it has spread over the entire 
country. Its habitat is along beaten paths, by dusty roadsides, and in 
similar locations. In the northern sections of the United States and 
Canada there are two varieties, or perhaps good species, which possess 
thin leaves and occur in entirely different habitats. These are listed 
by Fernald’ as Plantago major var. intermedia, which is found along salt 
4 Josselyn, John. Hew Englands rarities discovered: in birds, beasts, fishes, serpents, and plants of 
that country, p. 1-114 
§ Bigelow, Jacob. Bectie Bee . 1-268. 1814 
6 Oakes, Wm. Catalogue of Vermont inte: In History of Vermont, natural, civil, and statistical, 
by Zadock Thompson, part 1, p. 173-208. 1842. 
Be Fernald, Merritt L. Some recently introduced weeds. Massachusetts Hort.Soc. Trans. 1905:11-22. 
1905. 
