WORK OX TllK WIIJTI-: IMXK 1!USTKR Kl'ST IX MlXXKSO'l'A 
nurseries, and all primary infestations so far discovered occur within 
two miles of our eastern boundary. This is important in considerin.q' 
the possible source of Minnesota’s infestation. Up to date this disease 
has not been discovered in this state west of the Mississippi River, 
except on a few pines shipped from Nursery A and destroyed before 
blisters appeared. 
On September 25th, 1916, Mr. Coe, a held worker in connection 
with this disease, employed by the State Entomologist, and Mr. Salmon, 
working for the U. S. Bureau of Plant Industry, found in the course 
of a blister rust survey of the St. Croix reigon between Stillwater and 
Taylors Falls, a fourth "center" of infestation upon wild currants and 
gooseberries, close to the St. Croix at a point known as Pine Hollow 
Creek, three miles below Osceola on the Minnesota side. This discov- 
ery was made so late in the season that leaves were already falling and 
any attempt towards eradication would have been futile. Many of the 
pines at this point are undoubtedly now infested. This infestation 
appears most serious. It was first reported as covering an area of about 
thirty-five acres, but was later roughly estimated as covering fifty acres. 
Both here and at Dry Creek the deciduous growth is mingled with pines 
of various sizes. The latter place has a magnificent stand of large 
white pines, representing many thousand feet. In both localities pines, 
currants and gooseberries occur abundantly in ravines of varying width 
and length, and in these localities the disease was found most abun- 
dant. There a])pears to be a definite relationship between this abundance 
and the drawing of the wind up these miniature canyons. It is quite 
possible and even probable that further survey along the St. Croix will 
disclose the [)resence of the rust in other localities in that vicinity. 
POSSIBLE SOURCES OF MINNESOTA’S INFESTATION. 
While it is not ])ossible at this date to state definitely the actual 
source or sources from which Minnesota obtained this disease, beyond, 
of course, the one introduction of diseased trees by Nursery A in the 
spring of 1915, certain facts ])oint most strongly to the probaliility of 
its coming from Wisconsin. We know that diseased trees were brought 
to St. Croix Falls in 1908 or 1909, or in both years. It was a [)ortion 
of these trees planted at Lake Waupagasset, Polk County, Wisconsin, 
which first called our attention to the presence of the rust so near our 
eastern border, and which this year (and previously?) infested a large 
area in the neighborhood of the above mentioned lake near the St. 
Croix. 
