pe FARMERS’ BULLETIN 657. 
THE RIDGE AND COAL-TAR METHOD. 
Differing quite materially from the preceding are the various com- 
binations of coal tar or road oil and ridges of earth, smoothed and 
packed along the apex, or, instead of the ridge of earth, 6-inch boards, 
such as are ordinarily used for fencing, placed on edge and the upper 
edge coated with tar. 
Prof. 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 Forbes the coal tar was put upon the 
ground between a wheat field and a cornfield from an ordinary 
garden sprinkling pot from which the sprinkler had been removed 
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 already 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, Il., prepared 
for the coal-tar line by hitching a team to a heavy 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 receive 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 
renewed once each day and killed about 8 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 bushels of 
chinch 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 
1 Forbes, S. A. Twentieth Report of the State Entomologist on the Noxious and Beneficial Insects of 
the State of Illinois. Ninth Report of S. A. Forbes for the years 1895 and 1896, p. 39-40, Springfield, IIL., 
1896. 
