SPECIAL REPORT FOR YEAR I9I4. 29 



house as to result in spreading the disease in a manner far out 

 of proportion to their number. 



Assuming that only healthy, disinfected seed is used and 

 planted on clean soil, how may it and the resulting crop be pro- 

 tected from infected barrels, sacks, planters, potato houses, etc.? 

 From an experimental standpoint very little has been done as 

 yet to answer this question and some phases of it have not been 

 touched at all. However, there is available a large amount of 

 data regarding the effect of certain fungicides and germicides 

 upon the organisms causing common scab, blackleg, the Rhizoc- 

 tonia disease, etc. 



Planters and other tools which have in any way come in con- 

 tact with the germs of powdery scab should be washed clean, 

 then thoroughly washed or sprayed with a strong solution of 

 formaldehyde, one pint to five gallons, and allowed to stand a 

 few days before using. Barrels or other containers may be 

 handled in the same way. Sacks may be disinfected by soaking 

 two hours in formaldehyde the same strength as used for treat- 

 ing seed potatoes, one pint to 30 gallons of water, and then 

 drying. Doubtless a less expensive method for disinfecting sacks 

 would be steam sterilization at some central station. 



Corrosive sublimate and copper sulphate solutions have both 

 been recommended for disinfecting tools and implements. These 

 are undoubtedly as efficient for the purpose as formaldehyde 

 and are all right from the standpoint of the scientist, but the 

 practical farmer may experience difficulties with them, especially 

 with corrosive sublimate, which will not make him kindly dis- 

 posed toward them. Corrosive sublimate produces a very active, 

 corrosive action upon metals, especially upon iron — it being 

 necessary to always use wooden tubs or vessels for containers 

 in disinfecting seed tubers. Therefore, it is not adapted for 

 and never should be used upon the metal parts of good tools or 

 valuable farm machinery. While copper sulphate solution acts 

 upon iron this action is much less severe than is the case with 

 corrosive sublimate. Hence there is much less objection to the 

 use of copper sulphate solution. Formaldehyde solution, on the 

 other hand, when used as recommended, produces no more 

 injury to the tools than so rnuch water. 



Special attention should be given to empty storage houses. 

 All loose dirt and rubbish, including decayed potatoes or other 

 culls, should 'be removed from the interior and from around the 



