Mar. 17, 1919 



Fusarium-Blight of Potatoes under Irrigation ^97 



judge of the soil on any farm is the farmer who has worked with it. 

 Each parcel of land has its own pecularities, and advice on the handhng 

 of land should be specific. The very best conditions obtainable for the 

 potato should prevail throughout the season, and so long as the farmer 

 can control the environmental conditions no trouble is likely to result. 



CONTROL 



Control of Fusarium-bUght has not been attained. Different methods 

 have been employed, three of which offer reasonable hope of success. 



First selection of plants whose progeny will offer resistance to the 

 invading organisms. For this purpose, experiments are being carried 

 out vvrith standard accepted varieties known to be smted to the locality. 

 It is possible to select for resistance and have it gradually evidenced m 

 the performance of the plants, as in the field experiment noted above. 

 That is satisfactory so long as some overwhelming circumstance does 

 not intervene and wipe out the work of years. At best, resistance is but 



a relative thing. ■, ^ 



Second, control by seed treatment. The attempt has been made, not 

 to kill something that may be on the seed as in the orthodox seed treat- 

 ment but to coat the cut seed with a preservative or fungicide which 

 would remain vital throughout the season, preventing infection. Could 

 this be done, it would offer an easy solution to the problem. Expen- 

 ments were carried out in 1917 to test out the effect of different solutions^ 

 None of them gave satisfaction. Several lots of potatoes were treated 

 and planted on May 18, 1918, with several different mixtures and com- 

 pounds all of which for some reason or other were suspected of having 

 some possible preservation value. The seed used was the Rural variety, 

 and was cut in the usual way. The method of appUcation depended upon 

 the nature of the fungicide, aijd this is noted under "Remarks" m Table 

 II One lot was treated ^vith a spore suspension of F. oxysporum for 

 comparison. On June 19, 191 8, a similar experiment was made with a 

 few lots. The results of these experiments are given m Table 11, and 

 are the data taken from counting 600 plants. 



