21 



with tar. Forbes has reported excellent results from the application 

 of a line of coal tar put directly upon the bare ground where the surface 

 has been rendered compact by a recent fall of rain. Even in this 

 series of protective measures kerosene can be used to great advantage. 

 In the experiment recorded by Professor Forbes the coal tar was put 

 upon the ground between a wheat field and a cornfield from an ordi- 

 nary garden sprinkling pot from which the sprinkler had been re- 

 moved and the orifice of the spout reduced in size with a plug of wood 

 until the tar came out in a stream about the size of the little finger and 

 made a line on the surface of the ground about three-fourths of an 

 inch in width. Post holes were sunk along the line from 10 to 20 feet 

 apart on the side next to the wheat field, thus practically completing 

 the barrier, and the chinch bugs, being unable to cross the line of tar, 

 accumulated in the post holes in vast numbers, where they were 

 killed, and those bugs that had alread}'^ entered the cornfield before the 

 barrier was constructed were prevented from spreading farther by 

 tar lines between the rows of corn, the infested corn itself being 

 cleared of bugs by the application of kerosene emulsion. The same 

 writer states'^ that several farmers in Vermilion County, 111., pre- 

 pared for the coal-tar line by hitching a team to a heavj^ plank and 

 running this, weighted down with three or four men, over the ground 

 once or twice until a smooth, hard surface had thus been made to re- 

 ceive the tar. If the barrier was to be made in sod, a furrow was 

 plowed and the bottom of this made smooth by dragging the plank 

 along the bottom. In both cases post holes were sunk along the tar 

 lines, and in these were placed cans or jars into which the bugs fell in 

 myriads and were destroyed. 



On one farm of 250 acres a coal-tar line 90 rods in length was re- 

 newed once eacli day and killed about S gallons of chinch bugs. In 

 the case of another farmer there were 300 rods of tar lines with post 

 holes, cans, etc., which resulted in destroying about 10 bushelg of 

 cliinch bugs. A 6-gallon jarful was destroyed in less than half a 

 ■ day at one point on the line. In this last instance the lines of tar 

 were renewed three times a day, but even then less than a barrel of 

 tar was used. Still another farmer, with 120 rods of tar line, used 

 about a third of a barrel of tar and did not lose a hill of corn; he 

 caught chinch bugs by tlie bushel. In some of the cases cited the 

 tar line was run in a zigzag course, the post holes being situated at 

 the angles, and in others leader tar lines w^ere run obliquely to the 

 main tar line, one end terminating at the tra})hole, but both of tliese 

 plans were afterwards regarded as unnecessary, a single straight line 

 being entirely sufficient and less expensive. The numerous cases 

 where these methods were put into execution with entire success and 



a Twentieth Report State Entomologist of Illinois, p. 39, 1898. 

 [Cir. 113] 



