DEPARTMENT REPORTS. 211 



inspected, but in all cases we have notified the consignees of the danger 

 of bringing in injurious insects and have asked them to carefully ex- 

 amine the trees and plants. 



From the fact that all of these shipments have previously been inspect- 

 ed in the nursery by state and Federal officials, we felt this would make 

 the shipments comparatively safe. To inspect all of the shipments would 

 double the present cost of nursery inspection. 



Early in June the Federal authorities requested the inspection of 

 several shipments of cranberry vines from Massachusetts which were 

 shipped before the quarantine was established, and which had not been 

 inspected. Although the egg masses of the gypsy moth are frequently 

 found upon cranberry vines in Massachusetts, we were unable to find 

 any indication that the insect has been brought to Michigan. 



WHITE PINE BLISTER RUST. 



For several years considerable harm has been done to the white pine 

 in New England, New York, New Jersey and Pennsylvania by the blist- 

 er rust. It has also been found in Ohio and Indiana, and this spring 

 white pines in several places in Wisconsin and Minnesota have been 

 found to be infected. 



Owing to the fact that extensive plantings of white pine have been 

 made in Roscommon and several neighboring counties by the Public 

 Domain Commission, by Messrs. Ward and Mershon in Crawford county, 

 and by the Cleveland Cliffs Company in Marquette county, as well as 

 by hundreds of small planters over the State, it is important that steps 

 be taken to prevent the introduction of the disease upon nursery stock. 

 Even before the quarantine against shipments of white pines from 

 Europe was put into etfect very few were imported, and comparatively 

 few, if any, shipments from the infested areas of other states have come 

 into Michigan, and most of these have been used for landscape purposes 

 upon private grounds near Detroit and other large cities. 



It, is very difficult to detect this disease, as it may remain dormant 

 in the tissues of the tree for several years - before it manifests itself 

 externally. Like many of the other rusts, the white pine blister rust 

 attacks the five-needle pines in one form, or stage, of its development 

 and then passes to the currants and gooseberries, both wild and culti- 

 vated, upon which it remains for the balance of the year, passing 

 through its other two stages, after which it again attacks the pines. 



There is, therefore, not only danger that the disease may be brought in 

 upon pine trees but it may be imported upon currants and gooseberry 

 plants and from them spread to pines growing in the vicinity. The 

 danger is somewhat lessened by the fact that the currant leaves only 

 are attacked and for the most part these are stripped before the plants 

 are dug. 



During the month of .June, Professor Roy G. Pierce, Forest Patholog- 

 ist of the Bureau of Plant Industry, U. S. Department of Agriculture, 

 came to Micliigan and the principal forest plantations, as well as sev- 

 eral of the private grounds upon Avhich white pines have been planted, 

 were inspected without finding any traces of the disease, and we have 

 no reason to think it has secured a foothold in Michigan. 



From the nature of the disease the most careful inspection will be of 



