PROGRESS REPORT ON THE EUROPEAN CORN BORER 15 
eral inches long often is removed from the base of the " butt " and 
discarded as refuse. Infested refuse of this character, unless 
promptly destroyed, may become a source of danger, especially 
when dumped along the banks of water courses. The original infes- 
tation in eastern New York, along the Mohawk River, is believed 
to be directly traceable to infested refuse from the broom factory at 
Amsterdam, previously mentioned as having received foreign impor- 
tations. It was also determined that occasionally the raw material 
is made into large brooms, for stable or other rough use, without 
any preliminary process or manufacture, and in such a manner that 
opportunity is afforded for the dispersion of any corn-borer larvae 
that might be contained therein. Moreover, it was determined that 
the sulphuring and other processes undergone by the broomcorn 
during manufacture was not always sufficient to insure the destruc- 
tion of all the larvae contained therein. Consequently there is a 
possibility that some kinds of brooms manufactured from infested 
material may serve to disseminate the insect. 
Concerning the infestations on the islands and along the shore 
of Lake Erie in Michigan, Ohio, and Pennsylvania, it is believed 
that they may have originated from the intensely infested area 
directly across the lake in the Province of Ontario. The history 
and intensity of this infestation near Saint Thomas and Port Stanley, 
Ontario, indicate it as probably the oldest colony of the pest in 
this region. The infestation in western New York possibly may 
have originated from this same source, although its origin is more 
obscure. 
The method of dispersion from Ontario may have been by flight 
of the moths or by drift of infested plant material in the waters of 
Lake Erie. A study of the wind and water currents in the Lake 
Erie region, in relation to the known habits of the insect, show the 
possibility of such dispersion through either of these agencies, as 
will be discussed in greater detail in another part of this bulletin. 
The origin of the Ontario infestation is thought by McLaine (£1) 
to be possibly traceable to large importations of broomcorn into 
Elgin and Middlesex Counties from central Europe during the period 
from 1909 to 1910, although no conclusive evidence has been obtained 
upon this point. 
HOST PLANTS 
HOST PLANTS IN FOREIGN LANDS * 
According to foreign authorities the most common economic host 
plants of P. nubilalis in the Old World are corn (or maize), hops, 
millet [Pcmicum rtviliacewii L.), hemp (Cannabis sativa L.), and 
broomcorn. Indian corn, or maize, however, appears to be the pre- 
ferred host of the species in the Old World and is usually mentioned 
as being more severely injured than any of its other hosts. Hop 
is considered to be second in importance as a host of the species, 
while millet, hemp, and broomcorn are commonly attacked when 
grown within the range of distribution of the insect. In regions 
where for climatic reasons corn can not successfully be grown, par- 
ticularly along the northern limit of distribution of the insect, it 
is able to subsist upon other plants, notably millet and hops, thus 
demonstrating that in its native habitat the species is not dependent 
