190 Proceedings of Indiana Academy of Science 



and a Fusarium was isolated from the few seeds that were plated out. 

 This trouble was probably attributable to the wet weather. 



Spinach. — Downy mildew (Perouospora effusa) was found very de- 

 structive in two beds of spinach in a greenhouse at Lafayette on March 

 15. Large areas on the leaves wers covered with the gray coating of 

 sporophores and spores and the older leaves were dying from the 

 effects of the disease. Infected leaves were, of course, unsalable, and 

 the disease caused a considerable loss to this grower. In spore germina- 

 tion tests it was determined that temperatures of 4° to 27° C permitted 

 germination, but that only a low percentage germinated at temperatures 

 of 20° and above, vv-hile prompt and vigorous germination occurred at 

 4°, 9° and 16° C. The temperature of 9° seemed to .be the optimum 

 for germination while 16° seemed more favorable to subsequent growth 

 of the germ tube. 



In a plot of spinach grown under Skinner irrigation in a market 

 garden at Lafayette, about 50 per cent of the plants were found affected 

 with a destructive crov;n rot on June 21. The plants were of a market- 

 able size at this time and the loss was great. The affected tissue of the 

 recently affected stems and petiole bases was water soaked and dark 

 green. From diseased plants, a very rapid-growing Phytophthora species 

 was isolated. Spinach blight or mosaic was noted near Goshen on Sep- 

 tember 22. Nematode root-knot was also noted in the same region. 



Squash. — Oval, sunken lesions resembling anthracnose were found 

 on small white squashes in the local market on February 7. The fungus 

 isolated proved to be a Glceosporium .species not identical with the 

 cucurbit anthracno.se fungus. In pure culture this fungus was found 

 to grow fairly well at 9° and 16° C, and more vigorously between 20° 

 and 35°, with a fairly distinct optimum at 27°. 



Strawberry. — Leaf-spot caused by Mycosplmerella fragariae was 

 rather severe this season near Lafayette. The disease was noted in 

 Lake county and was reported from Clark and Kosciusko counties. Le- 

 sions bearing an abundance of viable conidia were found on green over- 

 wintered leaves in a garden near Lafayette on April 19. 



Sweet Potato, — Black rot, caused by Ccratostoniella fimhriatu was 

 the cau.se of storage loss in the 1920 crop in Jay County and badly rotted 

 roots were received from that county on April 29. W. J. Piggott re- 

 ported the di.sease prevalent in the 1921 crop in Knox County, and it 

 was noted by Gregory in Floyd and Tippecanoe counties. 



Fusarium stem-rot or wilt was noted in the Indianapolis market 

 gardens on July 12, and at Vincennes on June 28. Gregory reports the 

 disease destructive in Floyd County. A complaint of serious difficulty 

 due to this disease was received from a grower in Boone County and 

 growers in Carroll County reported this disease severe on the Yellow 

 Jersey variety but not on the White Yams. 



Scurf, caused by Monilochaete^ infuficans, was sent in from Jay 

 County on stored roots of the 1920 crop and also caused a very bad dis- 

 coloration of Yellow Jerseys grown at Lafayette from seed secured 

 from Vincennes. Specimens of Fusarium surface rot were sent in from 

 Union County on Sept. 10, and a Fusarium was isolated from the lesions. 

 The same roots were also affected with a very objectionable trouble ex- 



