62 THE MONTHLY BULLETIN. 



The formaliu treatment for scab had no appreciable effect on the vitality 

 of the worms in the tubers. We are now carrying on experiments with 

 other substances, but so far have found nothing which appears feasible 

 as an exterminator. 



The practical farmer is not so much interested in the scientific details 

 of our studies on the effects of the parasite on its host, or the peculiarities 

 of its life history and habits, as he is in remedial measures. In the 

 light of our present knowledge these, with special reference to the 

 potato, may be summarized as follows : 



1. Selection of potato seed from localities known to be free from the 

 parasite. 



2. Planting potato crops in noninfested ground. 



3. Summer fallowing of infested ground, keeping it free from weeds. 

 It is not yet known exactly how long the worms can live in soil kept 

 free from food plants but the indications are that one season will 

 starve them out. 



4. Deep plowing, preceding a period of hot dry weather, so that the 

 soil is well exposed to the heat of the sun and becomes thoroughly dried 

 out. 



5. Rotation of crops. The following plants are recommended by men 

 in the United States Department of Agriculture for use in crop rotation 

 as immune, or only slightly susceptible to the eelworms : barley, beggar- 

 weed, Brabham cowpea, broomcorn millet, corn, crabgrass, iron cowpea, 

 peanut, pearl millet, redtop, rye, sorghum, timothy, velvet bean, wheat, 

 winter oats. We have succeeded in getting a marked infestation of 

 corn and oats but even if these crops are not wholly immune they may 

 serve the purpose of greatly reducing the number of worms. 



