August, '14] HYSLOP: SOIL FUMIGATION 309 



quality of timothy hay, to continue the sod for from five to seven 

 years. The conditions are, therefore, ideal for experimentation of 

 the nature under discussion. The farm on which we sere working is 

 level and remarkably uniform in the matters of soil and drainage, the 

 latter, due to the contour, being artificial surface drainage by the 

 method known as "land ploughing," that is, leaving a dead furrow 

 every fifteen or twenty feet which drains into deep permanent ditches. 



The wireworms were attacking several crops other than corn, among 

 which might be mentioned potatoes, beans, carrots, wheat and mush- 

 rooms. Potatoes were riddled by these insects, as many as ten larvae 

 being found in a single tuber. As the worms were concentrated in 

 the potato hills these were the first to be treated to determine the first 

 and principal phase of the problem, namely, the efficiency, regardless 

 of all other factors, of the remedy in question. 



On October 1 cyanide was placed in fifteen hills by hand at the rate 

 of 300 pounds per acre, the treated hills being consecutive in the row 

 and with untreated hills on either side of the treated area. On October 

 4 three of the treated hills were dug out and examined. The larvse 

 were still numerous but inactive. They were in a very abnormal 

 attitude, being distended and straight, presenting a rigid corpse-like 

 appearance. Fift}^ of these larvae were collected and placed in small 

 tin boxes with moist sphagnum moss to determine whether they were 

 actually dead or merely temporarily overcome by the cyanide. In 

 several adjoining untreated hills all the larvae were active and normally 

 distended. Fifty of these Jarvae from untreated hills were placed in 

 boxes similar to the treated hill specimens as a check. At the end of 

 three days the two groups of boxes were examined. The larvae from 

 treated hills were all dead and had started to discolor while the check 

 specimens were alive and active. On October 9 the remaining treated 

 hills were dug out, no living insects of any kind were to be found in 

 the hills above the depth to which the cyanide had been introduced, 

 i. e., six inches. Many dead larvae were still to be found, while in all 

 the remaining hills of the patch, examined when the crop was dug, 

 living active larvse were still feeding on the tubers. Thus was the 

 first phase of the remed}^ conclusively proved in the affirmative. So- 

 dium Cyanide uill kill wireworms if correctly applied. 



The second experiment has not yet been concluded. It is being 

 carried on in a 20-acre field which has been in sod since 1910. This 

 field immediately adjoins the potato field in which the above experi- 

 ments were carried on. A strip containing one twentieth of an acre, 

 bounded on the east by the potato field before mentioned, on the west 

 by a piece of fall plough sod similar to itself and on the north by a 

 continuation of the same ploughing, has been treated by sowing, by 



