39 



On May 8 there were G additional cases of melon wilt with fruiting 

 Fusarium in the vessels of each one, and one melon plant had suc- 

 cumbed to a combination of Thielavia and nematodes. 



On ]\Iay 10 the cotton andcowpeas were coming up nicely, and more 

 of the melons had wilted. On May 21 there were 65 wilting melon vines 

 pretty uniformly distributed over the bed. Tlie cotton and cowpeas 

 growing between these rows of melons showed no signs of the wilt 

 disease. A few of them had rotted oft" at the base with Thielavia, but 

 no Fusarium was associated with it. At this time the cowpeas were 6 

 inches high with the first trifoliate leaf coming, and the cotton i)lants 

 were about 4 inches high with the lirst true leaf coming. I>y May 25 

 melons enough had wilted to make a total of about 100 cases. The 

 cotton and cowpeas were free from wilt and growing very satisfactorily, 

 considering how closely they were planted. By June 1 there had been 

 166 cases of melon wilt on this bed. All of these plants were examined 

 microscopically, and in every one there was an abundance of the Fusa- 

 rium in the vessels of the tai)root or stem, or both. In the recently 

 wilted plants the iiingus was restricted to the vessels; in those which 

 had been wilted some days, but were not yet dry- shriveled, it was also 

 in the parenchyma, but had not reached the surface. Only 16 healthy 

 melons remained, and these subsequently contracted the disease and 

 died. 



In digging and pulling out the diseased melons for examination the 

 roots of the cotton and cowpea plants must have been considerably 

 broken and disturbed, but neither in this way nor by the aid of the 

 Thielavia or of another fungus destitute of fruit, but resembling a 

 Pythium, was the melon fungus able to find its way into the cotton or 

 cowijea stems. 



Up to August 8, when the experiment was discontinued, all of the 

 cotton and cowpea plants remained free from this disease. At this 

 time they were large plants, and the cotton was suffering considerably 

 from crowding. 



ONE FUNGUS, OR THREE? 



It is my intention to repeat and extend the ascospore inoculation 

 experiments as soon as time permits, and also to settle more definitely 

 by means of additional cross inoculations whether under any circum- 

 stances the fungus from any one of these plants will ever transmit dis- 

 ease to the others. Much time has already been devoted to this 

 problem, which is one of great practical imi)ortance. From certain 

 cultural peculiarities of the fungi, from the uniformly negative results 

 of the hothouse experiments and from certain field observations, it now 

 looks as though these were separate diseases due to closely related but 

 not identical organisms. This is also the opinion of some very well- 

 informed growers. 



One of these field observations may here be given. In July, 1894, the 

 writer examined a large field of upland cotton belonging to Mr. T. S. 



