94 INSECT PESTS OF FARM. GARDEN AND ORCHARD 



dragging a heavy log back and forth in the furrow, making 

 the side next the corn as steep as possible.* In attempting 

 to climb this barrier, the dust will slide from under the bugs 

 and large numbers will accumulate in the bottom of the furrow, 

 where they will be killed by the heat of the soil if it has a 

 temperature from 110 to 120 (air temperature of over 90). 

 Keep the furrow clean by dragging a log through it now and 

 then. Sink post-holes a foot deep every few feet in the bottom 

 of the furrow and the bugs will collect in them and may be 

 crushed or killed with kerosene. Such a dust furrow will be 

 of no value in showery weather, and is most effective in hot dry 

 weather on light soil; it may often be used to advantage in com- 

 bination with the following methods. 



In place of the dust furrow or in combination with it, a strip 

 of coal tar is often run around the field. The strip, which should 

 be about the size of one's finger, can be made by pouring 

 from a watering can with the mouth stopped down, and should 

 be run inside the dust furrow and with post-holes sunk along 

 its outer edge. Sometimes it is run in a zig-zag line with the 

 holes at the inner angles so that the bugs will be concentrated 

 at the holes. These tar strips must be freshened whenever dust 

 or rubbish covers them. The soil may be prepared for the tar 

 strip by plowing a back furrow and packing the top with a roller 

 or beating it hard with spades; or a strip of sod may be prepared 

 by scraping away the grass with a farm scraper and then smooth- 

 ing carefully with shovels or hoes; or a dead furrow may be run 

 and the tar strip run on the smooth bottom. Instead of the coal 

 tar strip one of creosote may be used and is said to be even more ef- 

 fective. Difference in method of use is indicated in Fig. 72, 2. 



If the bugs have already become numerous in the outer rows of 

 corn, most of them may be destroyed by spraying with kerosene 

 emulsion (see p. 44) made to contain four per cent kerosene, apply- 

 ing it in the early morning or towards night. It costs 65 cents a 

 barrel diluted, and a man will spray five acres per day, using a 



* Such a furrow may possibly be made more readily by plowing several 

 lurrows and harrowing the ground thoroughly until reduced to a fine mulch 

 and then plowing a dead furrow through the middle, and then dragging this 

 with a log, making the sides as steep as possible. With such construction 

 the furrow will cost about five cents per linear rod. 



