Ill sdiiic ciiscs this (lisc'isc \v;is so dcsl riK'l i\c Hint liic crup \v;is plowed 

 iimlci-. Ill iitlici- liclds ii r.-iir .\ icld was secured. In urder tn prevent a 

 spread of ihr disease, stall' a iillKpril ies eninpelled tlie l.iirnin- nf the straw 

 from tile infested fields and a llioroiiuli disinfeel ion i<\' lla- i^rain in roriiial- 

 deh.vde. Xeiie of liie ^lain was allowed to he used for seed. Crowds were 

 advised not to plant wheal in tiiese lieids for several .vea rs. The cause 

 of (lie disease has not heeii deterniiiKMl. 



Ill c'oiiiioctioii with (he rather careful statewide search made for (he 

 aiiove (lisoiiso, a very ooiisideraMe aiiioiinl of frost injiiiy to wheal was 

 fiiiiml. This was ovideiu-ed hy a shriveliim and brown iliscoloralion of the 

 steins just ahdvo the nodes. 



Wiioat scab caused hy (Uhlxrclhi sduhiin Hi was the most serious wheat 

 diseasi'aiid was an important loss-prodiiciui; factor this season. As a result 

 of tho federal cereal disease survey, scab was found in 44-_' or 74% of the 

 .")!«; fields examined with an avera.ire incidence of IT'i. .lames Dickson, in 

 charge of this survey, reports cases of infection as Iiijrli as OO'/r in Orange 

 and Posey Counties. Pipal reiiorts authentic cases in Vanderbtirj:, Knox, 

 and Posey counties where the crops were not (»ven harvested and he esti- 

 mates that there was a ~}07( lo^^^ in l>ii«lly infected lieids in .general. 



Since recent investigation indicates that the wheat scab fungus lives 

 over winter on corn stalks the following observations are of interest. Pipal 

 reports an instance of a farm near Martinsville where .35% scab occurred 

 in wheat following corn and only a trace in the other field on fallow ground. 

 ( )n another farm the corn stalks were carefully removed from one acre in 

 a l.-irge lield planted to wlieat. This acre later showed ;>% scab as compared 

 with 10'; ill the rest of the field. From Dickson's re[iort it appears that 

 out of the i;i (ields examined in Hancock County, the percentage of scab 

 iaii,ged from ij to 4."»% in the six fields where wheat followed corn, with an 

 average of 20%, while in the seven fields which were not in corn in 11)18, 

 (he percentage of scab ranged from .5 to 75% with an average of 29%). 

 Among the latter is a case of (»()% scab following clover and another of 7."»%, 

 following wheat. From the same report it further appears that in the 10 

 lieids surveyeil in Posey ("ouiity, there was an average of 77%c> scab in the 

 four fields w Inch were in corn in 1J>1S and an average of G;l%- in the other 

 six fields. Furthermore, in the 10 fields surveyed in Orange County, there 

 was an average of 4.j%c scab in the six fields in corn in lOlS and 13%^ in 

 the other four fields. The evidence therefore is not conclusive and fact<trs 

 other than the corn must be considered. It seems quite likely that other 

 ]ilaiit residues are also of importance as a source of infection. Dickson 

 gives as his opinion that the two important factors are the abundance 

 of the parasite, and the presence of organic matter such as i)lant residues 

 on the soil for the propagation of the parasite. He intimates that the 

 preparation of the soil is as imi>ortant as the crop rotation utilized. Ac- 

 cording to Holfer, seed from diseased lieiuls yields weak plants but does 

 not constitute an important means of dissemination of the scab fungus. 



Ulinnphrov. Ilarrv B. and .lohnson, Aaron G. Tako-all and fla? smut, two wli.-at 

 diseases new "to the United States. U. S. Dept. Agr. Farmers' Bui. 100:5 :l-8. 1919. 



