646 



LABORATORY EXERCISES 



Clicstmil Bliglit {Endolhia {Diaporlhe) parasitica (Murrill) Anderson). — Inocula- 

 tion into the chestnut tree should be made into scarifications of the bark made by 

 means of a sterile scalpel. The bark should be washed before inoculation by means 

 of a weak formalin solution followed by distilled water. The summer spores can 

 be rubbed into place by means of a sterile platinum needle. 



AppeVs Potato Rot {Bacillus phyto- 

 phthorus, Appel.). — This organism read- 

 ily grows on beef agar. It is inocu- 

 lated into washed parts of the potato 

 stem by smearing some of the culture 

 on the stem and pricking into place by 

 means of a sterile cambric needle into 

 the young growing tissue. 



LESSON 32 



Sleepy Disease of Tomatoes {Fusarium 

 lycopersici Sacc). — This organism can 

 be cultivated on steamed rice, or on 

 potato slants. Inoculate just above the 

 lower leaves of the young stem by first 

 washing the stem with distilled water. 

 Place some of the culture on the part 

 of the stem to be inoculated and prick 

 the fungus into the stem with a sterile 

 needle. In ten to fifteen days, the 

 tomato plants begin to wilt and in 

 three weeks the diseased conditions are 

 unusually good for study. The culture 

 growths show pale orange spore masses 

 and a whitish mycelium. The tomato 

 variety Consate is not susceptible. 

 Wollenweber used the variety Stone 

 and found it satisfactory. 



Egg Plant Wilt {Verticillium albo- 

 Young corn plant showing ^ , ^ 1 ^ ^v i ^1 



th Pseudomonas atrum) .—Inoculate the hypocotyl near 

 or below the soil level with spores sus- 

 pended in water of a ten days old cul- 

 ture. Egg plants of any age may be inoculated. Black sclerotia are found in 

 from ten to fourteen days after the inoculation. This organism is readily grown 

 on potato slants. 



Wilt Disease of the Cotton Cowpeas and Watermelon {Neocosmospora vasinfecta 

 (Atkinson) E. F. Sm.).— See Duggar, B. M.: Fungous Diseases of Plants, pp. 233- 

 239; also Smith, Ekw. F. : Wilt Disease of Cotton, Watermelon and Cowpeas. Bull. 

 17, U. S. Division of Vegetable Physiology and Pathology, 1899. 



As plants of cowpea, cotton and watermelon have been grown in the greenhouse 



Fig. '229. 

 places for inoculation 

 Stewarti. 



