Indiana Plant Diseases, 1921 197 



coloration of the xylem tissue in the roots. Upon incubation in a damp 

 chamber, grayish mycelium bearing abundant Fusarium spores developed 

 from the vascular elements in the cut ends of roots and petioles. 



A rather destructive Alternaria leaf-spot was found in a patch of 

 turnips on muck soil near Goshen on Sept. 22. Whether or not this 

 was due to Alternaria brassicae is not known. A powdery mildew was 

 noted on turnips near Goshen, but no perithecial stage was observed. 

 The mosaic disease described last year (23) was noted at Lafayette on 

 July 22, and was found causing considerable damage in a patch near 

 Goshen on Sept. 22. As a result of the stunting effect of the disease, 

 the roots of many of the mosaic plants were small and worthless. As 

 Schultz (38) has shown, mustard is also subject to this mosaic disease 

 and mosaic was noted on mustard near Indianapolis on May 25. 



Watermelon. — Wilt, caused by Fusarium niveum, was noted at Vin- 

 cennes on June 28, and in Tippecanoe County on July 19. This disease 

 remains as one of the limiting factors in watermelon growing in Indi- 

 ana and, as was pointed out in the 1919 report, much of the suitable 

 watermelon soil has become infested with the fungus. It seems probable 

 that this wilt situation in Indiana is due to the fact, previously men- 

 tioned, that the good melon soils are confined to the sand ridges along 

 the rivers and that consequently, on any one farm, there is not very 

 much soil suitable for melons. This condition has resulted in a failure 

 to practice a long time crop rotation which would prevent the accumu- 

 lation of a soil pathogene. It is largely due to crop rotation that water- 

 melons can be continuously produced in the southern states. The wet 

 weather of late summer favored the development of anthracnose due to 

 Colletotrichum lagenarium and serious spotting of the fruits was noted 

 very generally in the local markets. Destructive leaf and stem infec- 

 tion was reported from St. Joseph County on Sept. 29. The non-parasitic 

 blossom-end rot which is usually followed by infection with rot-producing 

 fungi, was reported by one grower in Morgan County late in September. 



Wheat. — Gregory reported the prevalence of loose smut ( Ustilago 

 tritid) in southern Indiana early in June. He noted from four to ten 

 per cent infection in fields in Shelby County, as high as 25 per cent in 

 fields in Rush County planted with untreated seed, and five per cent in 

 one field in Posey County which was planted with grain descending from 

 seed treated in 1919. Loose smut was noted in Lake County on June 1 

 and in Allen County on June 6, and was sent in from Spencer County. 

 The hot water seed treatment at central treating plants is giving excel- 

 lent control according to reports received from a considerable number 

 of counties. Stinking smut (TiUetia foetans) was noted to a very limited 

 extent in a field in Elkhart County by Gregory and in a field in Tippe- 

 canoe County by Jackson. 



Hosmer found that stem rust {Puccinia graininis) occurred in a 

 destructive form only in the vicinity of barberry bushes, although there 

 was a very light infection in wheat throughout the state, which in- 

 creased in amount toward the south, according to Jackson. Stem rust 

 was noted in Tippecanoe County and was sent in from Jay County, and 

 Hosmer noted small amounts in Harrison and Franklin counties. The 

 latter observer found wheat fields practically ruined by stem rust near 



