Fusarium in Tuber l\<>t and Wilt of Potato 



1; 



( >n March 15 the following notes were taken. Series A: plant 1. 

 slight curling of leaves; 2. apparently sound; 3, curling of leaves; 

 4. curling of leaves. Sines B: plant 1. drooping leaves; 2, lower 

 leaves drooping, upper leaves drying; .■), apparently sound; 4, 

 apparently sound. Series C: plant 1, 'apparently sound; 2, some 

 wilting; 3, some wilting; 4. Mime wilting. Series D: plants 1, 2, 

 and 3. apparently sound; 4. wilting. By March 21 the plants 



A B 



Fig. 3. — Wilt produced in laboratorj with Fusarium oxysporum, and con 

 trol plant; A. control, Earl} Ohio variety; /•'. wilting of lower leaves and 

 curling of upper leaves, -l days after inoculation, Early Ohio variety. 



infected with F. ox\sporum showed a pronounced folding upward 

 of leaves on the midrib, wilting ami rolling on the margins of the 

 leaves, the folding being most pronounced in the tips of the plants. 

 The plants affected least showed discoloration on the margins, 

 which at times was of a yellowish tint, at times purplish to violet, 

 'fhe leaves of plants most severely affected showed a yellowing and 

 burning of the leaf margins. < >ne plant, inoculated with F. oxyspo- 

 ruin. developed a pronounced rosette, hut overcame this later, grow- 

 ing into quite a normal plant (figs. 4 and 5). These symptoms 

 remind one forcibly of certain symptoms of the leaf-roll disease 

 which has received SO much attention, and which has been made the 



