i82 Maine; agriculturaIv sxppe;rime;nt station. 1909. 



blight.* They were then placed in storage or shipped to 

 market. The weather following was quite warm and humid. 

 As a result of this infection, much of the stock which went to 

 market was a total loss, and in some cases the results in storage 

 were nearly equally bad. If a repetition of this disaster is to 

 be avoided, it will be necessary to first keep the blight off by 

 thorough spraying such as has been previously recommended 

 in this article. If blight does gain a foothold to any extent, 

 if possible do not disturb the crop till at least ten days after 

 the tops are killed by frost, two weeks will be better. There 

 will be some rot in any event if the tops show much blight, but 

 the net result of sound tubers in the end will be largely in favor 

 of late digging. 



OTH^R CAUSES OF DECAY. 



In closing this discussion it should be remarked that there 

 are present in the State two other potato diseases which cause 

 decay of the tuber and which cannot be prevented by any 

 amount of spraying. There is no evidence, however, up to the 

 present time, that either of these diseases have been a contribut- 

 ing factor to the epidemics of tuber decay which have occurred 

 in. Maine. One of these is the Fusarium dry rot which differs 

 from the late blight rot in that it nearly always begins at the 

 stem end of the tuber in the form of a brownish or blackened 

 ring a short distance below the surface, and the later stages of 

 the rot are more or less different also. The other tuber decay 

 is a soft bacterial rot caused by the same organism which 

 produces the Blackleg disease of the stem. Potatoes affected 

 by the late blight fungus usually develop a soft, stinking rot 

 in storage under moist, warm conditions, but the writer believes 

 that most of this decay is due to a secondary infection by 

 ordinary saprophytic soil bacteria which otherwise could not 

 attack the healthy tubers themselves. 



* This is not a mere supposition for the writer has assisted in per- 

 forming an experiment where these conditions were producted arti- 

 ficially with identical results. See Jones, L. R. and Morse, W. J. Vt. 

 Exp. Sta. Rept. 18, pp. 284-287 (1905). ' 



Director Woods also cites a similar experience as occurring in 1902. 

 See Me. Expt. Sta. Bull. 112, p. i (iQo.s). 



