2 MAINE) AGRICULTURAL EXPEJRIMENT STATION. I905. 



(4) Bordeaux mixture, and (5) a 3 per cent solution of formal- 

 dehyde. The 12 barrels were kept in the cellar until April. 

 There was very little further rot in either the untreated or the 

 treated barrels of potatoes. On the whole, about 90 per cent of 

 the tubers were still perfectly sound and free from discoloration. 

 This seemed to justify the conclusion, which other tests have 

 confirmed, that the danger of the transmission of rot due to the 

 fungus which produces the late blight from one affected potato 

 to another is remote. In this, as in other instances, the rot 

 undoubtedly resulted from infection in the field. As the tops 

 were kept green by the application of Bordeaux mixture and 

 there were so little signs of the presence of the blight, the infec- 

 tion could hardly have been through the vines. The field was 

 heavily dressed with stable manure only a short time before 

 planting. There is little doubt that the fungus was carried to 

 the field in the manure and that the tubers were directly infected, 

 while the tops escaped the attack. This is in accord with the 

 common experience so often noted before the use of Bordeaux 

 mixture, that potatoes were more subject to blight and subse- 

 quent rot when grown on manure than on chemicals, or without 

 the application of fertilizer of any kind. From the results of 

 the experiments that follow, it is doubtful if there would have 

 been anything like this loss from rot in the cellar, if the potatoes 

 had been allowed to remain a few days in the ground after the 

 tops had ripened, or after they had been killed by frost. 



LFFECT OF TIME OF DIGGING UPON SUBSFQUFNT DLVFLOPMLNT 



OF ROT. 



In 1903 a variety test was conducted to study the differences 

 in a few varieties in their abilities to resist blight. These results 

 were given in detail in Bulletin 98 of this Station. Advantage 

 was taken of this experiment to study the keeping qualities of 

 the potatoes, comparing different varieties, sprayed with 

 unsprayed, and early with late dug potatoes. At the distance 

 these potatoes were planted and with a uniform stand, fifty-five 

 hills almost exactly represents 1-300 acre. The yields at the 

 time of digging are given in the following table. 



