354 AGRICULTURE OF- MAINE. 



threads. The fungus does practically no liarm here, but gets in 

 its work in the summer when both it and the potatoes are grow- 

 ing. 



The next picture throws a flood of light upon the question of 

 the cause of the weak and uneven stands of some years. As you 

 see, the seed-piece sprouted all right, but portions of the sprouts 

 below ground have turned dark brown, one has been cut off, 

 and all three are so badly injured that they will never reach the 

 surface of the ground. 



We maintain and feel that we have proved, that this is caused 

 by the Rhizoctonia fungus. The next picture shows some pota- 

 toes which sprouted in sacks in the cellar, and the fungus 

 attacked them there. Some of the sprouts have been entirely 

 destroyed. The next shows another seed piece, the sprouts of 

 which have all been killed back but one and this will soon die. 



Along about the time the plants are about five to eight inches 

 high, and have been covered up once or twice, we frequently see 

 quite a percentage of them that are just peeping above the 

 ground. If you inquire of the owner of the potatoes the cause of it 

 he usually explains it as weak seed or one where the seed piece 

 fell so as to have the eye down and thus delayed the sprouts in 

 reaching the surface. The next three pictures show how some 

 of these plants look when dug up. In the first, the stem has been 

 attacked in various places near the surface, but not sufficient to 

 kill it as yet. You will note that differing from blackleg the 

 disease does not always start at the base and work upwards. 

 Another important dift'erence is that the lesions produced by the 

 Rhizoctonia fungus are brown and not black as in the case of 

 blackleg. The general appearance of the affected tops above 

 ground may be somewhat similar in the two diseases. In the 

 next picture several sprouts have been killed and the last one is 

 about to go. In the next, some have been killed and one of the 

 three remaining w^as so badly injured that it was easily broken 

 in digging up, and the others are nearly equally diseased. 



On a field that showed about i per cent of the plants affected 

 like this a later examination showed that 91 per cent of the 

 plants were attacked in one way or another. 



Oftentimes plants which are badly attacked and cut off, 

 branch out and send up new shoots which later grow into respect- 

 able looking tops, but produce only small potatoes. One of the 



