14 CIRCULAR NO. 129, BUKEAU OF PLANT INDUSTRY. 



continuod inspection will more than replace the diseased ])lantations 

 with healthy trees and this policy would be more economical to the 

 State than to continue mspection. The national quarantine law 

 prevents further imjiortations of this disease, thus removing a great 

 uncertamty regardmg its status. At least tln-ee of the States — New 

 Jersey,^ New York,^ and Connecticut^ — have already destroyed entire 

 shipments of white pines when the disease was found m them. The 

 destruction of mfected plantations is the logical contmuation of this 

 policy. It will rid the country of the disease and is apparently the 

 only sure method of doing so. 



VARIATIONS IN FRUITING. 



This fungus apparently varies much in the abundance of fruiting 

 bodies formed in different years.'' There can be little doubt that 

 weather conditions are largely responsible for this variation. In 



1911 relatively few diseased trees were found bearmg fruiting bodies 

 of the fungus, but in 1912 a large number were found with them, 

 even in plantations which had been carefully mspected before and 

 from which all the diseased trees were removed and destroyed one or 

 more years ago. Moreover, the trees which bore fruiting bodies m 



1912 had them in great profusion, some trees being found which bore 

 hundreds of peridia. This experience was quite general wherever 

 careful inspection of diseased plantations was made. 



A comparison of the monthly w^eather reports for the two years 

 shows the following conditions for New York and New England: In 

 March, 1911, the precipitation for some time had been so low that 

 many city and town water supplies were very low, so much so as to 

 cause serious apprehension. The precipitation for March, 1911, was 

 slightly less than normal; for April it was very light and the weather 

 was sunny ; for May the precipitation w^as hardly half of the normal 

 amount. These conditions the writer believes materially hmdered 

 the formation of fruiting bodies by the rust. In 1912 the conditions 

 were quite different. The drought which prevailed in the spring of 

 1911 was broken, and water supplie's began to assume their normal 

 condition. In March, 1912, precipitation was very heavy, more than 

 counterbalancing what the previous two months had lacked; April 

 had excessive precipitation and cloudy weather. May had heavy 

 precipitation, while June was somewhat deficient. Abundant pre- 

 cipitation just before the fruiting period, and even at that tijne, 



1 (Anonymous.) Forest Quarterly, v. 9, no. 2, p. 351-352, 1911. 



2 (Anonymous.) Op. cit., p. 359, 1911. 



8 Britton, W. E., and Walden, B. H. -Inspect ion of imported nursery stock in Connecticut. Connecticut 

 Agricultural Experiment Station, 12th Report, 1912, p. 222. 



■» II awes, A. F. Suppression of white-pino blister rust disease. ■4th Annual Report, Stale Forester, 

 Vermont, p. 21-24. In Agriculture of Vermont, 1912. 



[CMr. 129] 



