FIFTEENTH ANNUAL YEAR BOOK— PART XI 819 



CEREAL DISEASES. 



Rust of wheat (Puccinia graminis and P. rubigo-vera) was commonly 

 observed but not as destructive as during the wet years. A few season- 

 able rains for infection occurred in some parts of the state. Late sown 

 grain suffered more severely than the early. In an experimental plat 

 sown very late the rust was so severe that the plants did not head out. 

 There was also some rust (Puccinia gramiyiis) on the stems of oats and 

 leaf of oats (P. coronatg,) L. With us in Iowa, rye is quite as severely 

 rusted as wheat and that with Puccinia rubigo-vera. The yellow leaf 

 disease of the barley (Helminthosporium gramineum) and leaf spot 

 (H. sativum) were serious, in some cases materially reducing the yield 

 of barley. In Story county the former damaged the crop to the extent 

 of 4-15 per cent, while the latter occurred on from 50 to 60 per cent of 

 the leaves. It probably reduced the yield of barley 25 per cent in the 

 State. Of the barley smut the naked smut (Ustilago nuda) was most 

 common. The damage was probably not far from 22 per cent. For the 

 first time ergot {Claviceps purpurea) was common on barley. Oat smut 

 (Ustilago aveneae) was common and the damage has been estimated at 

 $7,000,000 this year. Too few of the farmers treat their seed with for- 

 malin to prevent the disease. No wheat bunt was observed. There was, 

 however, an abundance of wheat smut which damaged the crop to the 

 extent of 2 per cent. A bacterial disease of oats was observed in Clinton 

 county. The young oat leaves turned yellowish brown. 



DISEASES OF CORN. 



Corn is the most important crop in Iowa. The usual amount of smut 

 (Ustilago Zep.e) was observed, about one per cent; some rust {Puccinia 

 Sorghi), however not as severe as in 1912. An unusual and widespread 

 disease of corn caused by fungus Fusarium appeared in nearly every part 

 of Iowa. In some cases the loss from this fungus was 50 per cent, in 

 other cases 6-15. The yield for the whole state was materially reduced. 

 In this disease the roots were diseased, having a pinkish color,the wind 

 blew over the corn, many such stalks were barren. In other cases the 

 fungus attacked the stem, destroying the pith and causing the corn to 

 fall over, usually breaking close to the joint. The damage caused by this 

 fungus has been estimated at nearly $25,000,000. The disease was not 

 local but quite general in the state. It is probable that the lack of 

 moisture checked the development of roots and thus materially injured 

 the corn when attacked by the fungus. There was also much complaint 

 about ear rots. These have not been connected with root or stem disease. 

 "While the moist weather of September may have contributed somewhat 

 to the abundance of this mould {Fusarium) , it is a true parasite. 



POME FRUIT DISEASES. 



The apple crop was so small this year that not much need to be said 

 about pome diseases. There was in some sections of the state a little 

 apple scab on the fruit, but more abundant on the leaves especially such 

 varieties as Fameuse. Illinois or Blister canker {Nummularia discreta) 



