35 



COTTON AND COWPEA INOCULATIONS, CROSS INOCULATIONS. 



All of tlie cottou-plaiit inoculations have failed. These also were 

 soil inoculations, and were performed on many small plants, using the 

 cotton fungus, the cowpea fungus (cultures from ascospores), and the 

 melon fungus. The experiments were re])eated in diflferent years and 

 were continued in some cases for a long time with both sea island and 

 upland cotton. 



Melon-plant inoculations, on a large scale, also failed when the cot- 

 ton fungus was used. These were soil inoculations. Py thiuui attacked 

 and destroyed some of the plants and injured others, but no Fusarium 

 disease ai)i)eared. The above statement should be(puilitied as follows: 

 In the fall of 1894, 25 pots of melons were infected with the cotton 

 fungus soon after the seeds were planted. For some weeks Pythium 

 caused a good deal of trouble, and in one of the i)latits attacked by this 

 fungus a small quantity of mycelium bearing the internal conidia of a 

 Fusarium was found in the base of the stem. More cases, and typical 

 ones, were anticipated, but they did not appear. 



Cowpea inoculations also failed with both the melon and the cotton 

 fungus. These were soil inoculations on plants in all stages of growth, 

 from seedlings to plants two months old. Many plants were used, and 

 the experiments were continued from four months to more than a year. 

 The soil was copiously infected with the fungus, and repeatedly in some 

 cases. Watermelons planted between the rows of cowpeas readily 

 succumbed to the disease when the melon fungus was used. The above 

 statement should be qualified as follows: On November 16, 1895, 182 

 cowpea seeds were planted in 26 pots of soil, in each one of which sev- 

 eral melon plants had wilted the preceding June. The jilants grew 

 healthily all winter, but on February 14 the lower leaves of one plant 

 began to wilt, and six days later the few remaining leaves fell off at a 

 touch. The stem was green and appeared to be healthy except at the 

 surface of the earth, where it was brown and partially rotted off, as 

 when attacked by Thielavia basicola. In the upper part of the tap root, 

 in the vicinity of this injury, the walls of some of the vessels were 

 browned, and a few of these vessels were packed full of a fungus bear- 

 ing the internal Fusarium conidia. More cases, therefore, and typical 

 ones, were anticipated, but none appeared, although the plants were 

 kei)t under observation for a long time. 



Cowpea inoculations failed with the fungus derived from ascospores 

 of the cowpea fungus. Nine large pots were used, but all of the 170 

 plants remained free from disease distinctly attributable to the Neocos- 

 mospora, although under observation for many months. These were 

 soil inoculations, and an abundance of the fungus was used. A few 

 melon plants grown in these same pots also remained free from disease. 



Tomato plants in quantity were grown for a long time in soil full of 

 the melon fungus without contracting any disease. This was done 

 because a Fusarial disease of tomatoes occurs in Florida and also in 



