282 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 4 



TREATING SEED CORN FOR WIREWORMS 



By H. T. P'ernald, Amherst, Mass. 



A previous number of this Journal (II, No. 4, 279, 1909) con- 

 tained a note referring to experiments for the purpose of protecting 

 seed corn from wireworms. In that note it was stated that the 

 tests had progressed to a point where it seemed desirable to repeat 

 them on a larger scale, and in different parts of the country. 



During the past year, reports of quite a number of these tests 

 have reached the writer, and have indicated a wide difference in the 

 results obtained, some reports being very favorable, while others 

 condemn the method in the most unqualified terms. To reconcile, 

 if possible, these results, considerable correspondence has been neces- 

 sary, but the final outcome has suggested certain factors as being 

 responsible where failure was reported, and these are here considered. 



In all the cases where the treatment was reported as unsuccessful, 

 the failure of the seed to germinate was the nature of the complaint. 

 This seems to have been caused- by one of several reasons. Some experi- 

 menters appear to have used coal tar instead of gas tar, which may 

 have been the cause. At Amherst, gas tar from the town gas works 

 was the material used. In other cases, the tar was applied without 

 thinning, and thus probably coated the seed with a layer so thick and 

 impervious to water that it was impossible for germination to occur. 

 In the original experiments the tar was mixed with linseed oil until 

 it was quite thin, and under these conditions, all the seeds germinated. 



Some experimenters apparently coated the tarred seed with Paris 

 green unmixed with road dust, or any other diluent. While this 

 would probably have no effect upon the germination of the seed, 

 it is, at least, evidence that complaints which come from persons 

 who do not follow directions, may be the result of failure in any of 

 a number of points besides the one or ones actually ascertained. 



On the whole, the method suggested can hardly be considered a 

 failure, in spite of the criticisms it has received, until further tests, fol- 

 lowing the correct method, shall have demonstrated its worthlessness. 



During the past season a modification of the above method has 

 been tried with some success. Mr. R. D. Gilbert of the Bowker 

 Insecticide Company, Mr. R. H. Whitcomb on whose farm and by 

 whom the experiments were conducted, and the writer were all con- 

 cerned in these tests, and desire to carry them further. 



This metliod obviates the necessity of two treatments of the seed, 

 first with tar and then with Paris green, bj' using a paste arsenate 

 of lead. In the particular experiments here reported, Disparene 



