April, '17] WASHBURN: WHITE PINE BLISTER RUST 277 



which received no inspection. On account of the intermittent kiUing 

 on farms, the fly conditions there are far less objectionable than in the 

 small slaughter houses. The fly conditions in most abattoirs not under 

 inspection are beyond description, and one need but to pass through 

 one of these and one of those plants receiving proper inspection to be 

 convinced of the undesirabihty of buying uninspected products and the 

 Beed of state or municipal control over such establishments. It may 

 be said that most of the fly control measures found applicable for use 

 in government inspected plants are equally so in the uninspected ones 

 though some modification is often necessary. The first step toward 

 mitigation of the fly trouble is to secure effective supervision and con- 

 trol over such plants. Where incineration is not feasible, prompt 

 burial under two feet of soil after the offal has been sprinkled with 

 borax, the thorough screening of buildings and the installation of 

 covered drains will accomplish much in reduction of fly numbers. 



WORK ON WHITE PINE BLISTER RUST IN MINNESOTA, 



1916 



By F. L. Washburn 



Abstract 



The rust has been discovered in four places only along the eastern 

 boundarj^ of Minnesota, close to the St. Croix river, two of which are 

 nursery infections. One of these nurserymen is known to have brought 

 diseased trees from an old nursery in Wisconsin, just across the river, 

 said trees being a portion of a lot shipped through Hill of Dundee, 111., 

 to a Wisconsin nurseryman in 1908 or 1909. We have worked in 

 close cooperation with the Plant Pathology Department, aided in part 

 by the State Forestry Service. Camp was established on the St. 

 Croix river, and scouting under the direction of the State Entomologist 

 was carried on up and down the river for a distance of about fiftj^ 

 miles, with the results as above stated. In the two nurseries men- 

 tioned, all five-leaf pines and all currants and gooseberries were de- 

 stroyed by burning, said nurseries being under quarantine as regards 

 this material until destruction of same. Shipments from these nurs- 

 eries designated as "leads" were traced and destroyed wherever the 

 slightest suspicion was entertained of the presence of blister rust. In 

 the neighborhood of Dry Creek eradication area was outlined and all 

 Ribes within the area as far as possible destroyed by workmen and 

 experts in the employ part of the time by the State Entomologist and 

 a portion of the time by the federal government, although federal funds 



