DISEASES OF CULTIVATED PLANTS 553 



including tops, smutted sets and infected earth, would be greatly 

 improved in this respect by burning. Under the head of treatments 

 to be applied in planting, formalin and stone lime are both promis- 

 ing, if the present season's results are found capable of repetition 

 on a large scale. It would seem possible to increase the percentage 

 of formaldehyde, of forty per cent strength, or formalin such as 

 herein mentioned, to one-half per cent solution, or 1 pound to 25 

 gallons of water, or 1 ounce to l 1 /^ gallons. Upon this point I would 

 advise the use rather of a three-eighths per cent solution, 1 ounce to 

 2 gallons of water, for all save smaller experimentation until the 

 safety of a greater strength is established, likewise its greater effi- 

 ciency, which can now only be inferred. 



It seems necessary to apply the formalin solution in some man- 

 ner as that before described, although there should be nothing incom- 

 patible with hand carts, sleds and the like in devices for making the 

 rows and sprinkling the solution. Horse implements can scarcely 

 be used at these stages because of the effect of trampling. A barrel 

 containing the solution and mounted upon a cart should prove a 

 means of easily applying the formalin by rose (sprinkler) suitably 

 connected. In the application of lime the usual methods of applying 

 by spreading stone lime before slaking, or better, the ground burnt 

 lime, should prove sufficient. It does not seem probable that more 

 than one hundred and fifty bushels per acre will be required and a 

 less amount may prove equally effective. Where set growers have 

 smut infected land to plant it is advised to use lime on one strip; 

 formalin on another, and both together on yet another of equal area, 

 alternating with at least two untreated strips of equal size to test 

 field results. 



Summary. This onion smut infests the soil into which it has 

 become introduced and attacks onions growing from seed in such 

 soil. It does not attack sound sets or mother onions. The onion 

 smut is not introduced into onion seed if properly handled, but much 

 more probably in onion sets or infected onions. It may be spread 

 in a variety of ways. Preventive treatment and measures of avoid- 

 ance seem necessary to preserve the onion set industry from abandon- 

 ment in parts of one district. The treatment measures indicated by 

 the preliminary experiments recorded in this bulletin consist in the 

 application of stone lime and in the use of forty per cent formalde- 

 hyde commercially known as formalin. (Ohio E. S. B. 122.) 



To apply formalin use at a rate of 1 pound formalin to 37^ to 

 50 gallons of water (1 oz. to 2 or 3 gallons) and apply with sprinkler 

 upon the scattered seeds until well moistened, then cover with earth 

 promptly. 



Apply stone lime after the usual methods, spreading before per- 

 mitting it to slake, either in the usual form or finely ground soon 

 before seeding upon the prepared land. Harrowing may follow, 

 and immediately precede the seeding of this land. Ground lime ad- 

 mits of easier application without increase of cost. ''Ohio E. S. B. 

 122.) 



