148 AGRICULTURAL APPROPRLA.TIOX BILL, 1024. 



Mr. Buchanan. You know the objection to that, do you not? 

 This root rot takes possession of a patch of perhaps an acre over 

 there and an acre over here and another acre over there [ilkistrating], 

 just in Uttle patches throughout the cotton field. 



Doctor Taylcjh. Yes: that is the difficulty. 



Mr. BuniANAN. And you would have the grass patches or sorghum 

 patches scattered all over the field and have the exact line of the 

 root rot. ^ 



Doctor Taylor. It becomes a very difficult thing, unless you are * 

 operating on a basis that would permit the use in otiier crops of the 

 whole tract that has some bad spots in it. 



Mr, Buchanan. But the spots are not sufficient, you know. 



Doctor Taylor. And that is not economically sound in many 

 cases. 



I will ask 3^ou, Doctor Kellerman, to tell the committee of one 

 recent development that you have been in special touch with in 

 root-rot control that is interesting. 



RECENT DEVELOPMENTS IN ROOT-ROT CONTROL WORK. 



Doctor Kellerman. In the Southwest the root rot has become a 

 very serious factor in the new cotton areas, especially in these areas 

 where the bureau has been fostering the production of Pima cotton — 

 long-staple Egyptian cotton — that is, American Egyptian cotton. 



Mr. Buchanan. That is in Arizona and California ( 



Doctor Kellerman. That is in Arizona and California. The experi- 

 ments on the control of root rot, I believe, have pro^rresseil further 

 than they have in any of the older cotton areas and we have had 

 during the past two years remarkably successful control by treating 

 infected areas of a field with a solution of formalin — that is a disin- 

 fectant used widely; it is an excellent fungicide; furthermore, it 

 breaks down after it has been in the soil a while, so that it does not 

 injure the soil agriculturally at all. 



Mr. Buchanan. Do you apply that to the soil ? 



Doctor Kellerman. Yes; to date this treatment has been made 

 only in irrigated regions, which simplifies the application of the 

 disinfectant, because the area to be treated can be oankeil up, irri- 

 gation water run onto it, and the formalin added to the irrigation 

 work. . 



There appears to be no reason, as far as we can see, why somewhat 

 stronger solutions could not be used in connection with plowing or 

 harrowing operations, and actually apply either formalin or some 

 similar disinfectants in regions where irrigation is not practiced. In 

 any case, it has been possible to check immediately, and, from some 

 exi)erimental fields, to completely eradicate the cotton-root rot. ■ 



Mr. Buchanan. Have you estimated the cost of formalin per acre '? " 



Doctor Kkllerman. (Jn a field that was bailly infci-ted il would 



f)robably not be practicable. We have not estimated it on that 

 )asis, but on the small cjuantity of land that neeils to be trealeil 

 when infection is starting it amounts to only a few dollars per acre - 

 two or three dollars to the acre on the liclds we have had uiuler 

 consideration. We find that the disease progresses from a central 

 point. 



