11 



the spring. On July 28 the writer went over this field of corn care- 

 fully and found that over the spring-plowed portion nearl}^ every hill 

 of corn was infested by the root-aphis. The crop was an almost com- 

 plete failure. Much of the corn had been killed out previous to the 

 time of the writer's visit and the remaining part was dwarfed in growth, 

 bore few ears, and such as it had were very small and almost worthless. 

 All over the winter-plowed portion, however, there was every pros- 

 pect of a heavy yield of both stalk and ears, even to the narrow head- 

 land previously mentioned. An assistant, Mr. Ainslie, visited the field 

 in late September and was able, without information from any person, 

 to locate, to a row, the dividing line between the two plowings. This 

 was clearly visible on account of the difference in appearance in the 

 stu])ble — the corn having by this time been cut and shocked — and also 

 on account of the number, size, and appearance of the shocks. There 

 was a diflerence of fully two-thirds in favor of the winter-plowed por- 

 tions of this field. As the jneldof the winter-plowed portion was ap- 

 proximately To bushels per acre, the spring-plowed would not exceed 

 25, showing a probable loss of about 50 bushels per acre. At the 

 market price, 75 cents per bushel, the loss would amount to §37.50 

 per acre, to which must be added the loss in fodder. These figures 

 show quite conclusive!}" the amount of damage this root-aphis is capable 

 of doing, as well as what can be accomplished in the v^ay of prevention 

 by thoroughly practical methods. 



THE USE OF BARNYARD MANURE. 



It seems to be a fact, borne out by field observations, that where 

 ground has been fertilized with barn3'ard manure the root-aphis does 

 not become so destructive. As far back as 1886, on the experiment 

 farm of Purdue Universitj", at Lafaj^ette, Ind., the writer made some 

 observations which led to the conclusion that proper fertilizers applied 

 to the soil are a general preventive of damage. This was clearly proved 

 by the appearance of the crop on a series of eighteen plats on the uni- 

 versity farm. These plats were located side bj^ side and numbered 1 

 to 18. All had produced corn for the previous six crops, those plats 

 of even numbers not having been fertilized during that time. Plats 



I, 7, and 13 had, three and again two years previous, received appli- 

 cations of gas-lime; plats 3, 9, and 15 had received applications of 

 superphosphates during the same years, while plats 5, 11, and 17 had 

 received similar treatment with barnyard manure. The result, up to 

 July, 1886, was that the corn on all ])lats except those fertilized by 

 barnyard manure was small and uneven in growth, while on plats 5, 



II, and 17 the plants were fully a third larger, more thrifty, and far less 

 uneven in height. In fact, these plats could be distinguished from 

 any of the others at a distance from the field. It was unfortunate 



[Cir. 86] 



