236 BOARD OF AGRICULTURE. [Pub. Doc. 



son the growth on these leaves changes in its form, and the 

 spores now produced will grow in anv five-leaved pines to 

 which thej may be carried by the wind. 



This disease is a very dangerous one, and if it should be- 

 come established in this State any attempts at reforestation 

 with white pines might as well be given up. Recognizing 

 this, and knowing that the disease was actually being brought 

 into Massachusetts on white pines imported from Europe, 

 an order was issued prohibiting the importation of trees liable 

 to the disease after June 1, 1912. A similar prohibiting order 

 applying to the entire United States was issued by the Federal 

 Horticultural Board Sept. 16, 1912, and as a result of these 

 actions there is no longer any danger of new cases of the dis- 

 ease reaching the United States while these orders are in 

 effect. 



The danger from diseased pines imported before June, 

 1912, remains, however, and during the past year it has been 

 attempted to examine all the pines imported into Massachu- 

 setts since 1905. It has been very difiicult to learn of all such 

 imports, but many have been found, and in some cases the 

 disease has been found on the trees. 



In this work it should be remembered that the disease 

 though present does not show on the tree, sometimes, for sev- 

 eral years, working entirely inside. This must mean exami- 

 nation of all suspected plants at least once a year for a num- 

 ber of years. The best time for this is during May and June, 

 as then the spores, if any are to develop on the ontside that 

 season, will be in evidence. Later in the year an inspection 

 of the currants should show the disease if diseased pines are 

 in the vicinity. During the past year these inspections have 

 been carried out as far as time and funds would permit, and 

 the result has been to locate the blister rust in quite a num- 

 ber of places where it was not hitherto kno^\^l to be present. 

 To extend our knowledge of the distribution of this danger- 

 ous disease, and to eradicate it as rapidly as possible, either 

 by the destruction of the infested pines or currants, as the 

 case may be, are the next steps, and it is planned to continue 

 work on these lines the coming season. 



Massachusetts ranks fourth among the LTnitcd States as 

 regards the amount of nursery stock imported, and the ex- 



