120 RODENTS OF IOWA 



In Iowa, control of the pocket gopher is best effected in one of 

 two ways, trapping' or poisoning. If the numbers of the pests 

 are not great there is little to choose between the two methods, but 

 if the animals are abundant or distributed over large areas poison- 

 ing is the cheaper and more efficient method. 



Poisoning. — Among the baits that may be successfully used are 

 parsnip, sweet potato, Irish potato, carrot, beet, celery, and sugar 

 beet. Any of these maj- be cut up into small cubes and poisoned 

 with strychnia sulphate by inserting a few crystals in a slit made 

 with the point of a knife. Prunes or raisins may be used in place of 

 the vegetables with as good results. 



After the baits have been prepared, the tunnels are located by 

 using a probe made of a spade or hoe handle shod with a metal 

 point aiid with a metal cross-bar for the operator's foot about 

 fifteen inches above the point. When this probe is withdrawn it 

 leaves a hole through which tlie poisoned bait may be dropped 

 into the runs. The liole may be left open or closed with equally 

 effective results. 



Another method of poisoning gophers which has proved effective 

 in North Dakota and which is recommended by the United States 

 Biological Survey, is the placing of cubes of sweet potatoes or 

 parsnips in their underground burrows. The following simple 

 directions will prove useful : ' ' The bait should be cut about an 

 inch long and a half inch square and washed and drained. From 

 a pepper box slowly sift % ounce of powdered strychnine (alka- 

 loid) and 1/10 of this quantity of saccharine (ground together in 

 a mortar) over about 4 quarts of the dampened baits, stirring to 

 distribute the poison evenly. 



"The runways, which are usually 4 to 8 inches beneath the sur- 

 face, can be located by means of a probe made of any strong handle 

 an inch in diameter and 36 inches long. One end should be 

 bluntly pointed. Into the other end should be fitted a piece of % 

 inch rod, protruding about 12 inches and bluntly pointed. A foot 

 rest aids in probing in hard soils. By forcing down this iron 

 rod near gopher w'orkings, or a foot or two back of fresh mounds, 

 the open tunnel can be felt as the rod breaks into it. The blunt 

 end of the instrument is now used to carefully enlarge the hole, a 

 bait or tw^o is dropped into the run and the probe hole closed. 



"One soon becomes expert in locating the runs, and a man can 

 treat 300 to 500 gopher worldngs in a day. Baits need be placed 



