10 



farmers' bulletin 932. 



Avicle ilistribution. Tliev incliulo many species and varieties, all 

 nearly similar in habits and alike (U\structive. Many forms inhabit 

 mountains and deserts, where they do not injure ag-ricnlture. Others, 

 however, live in the richest alluvial soils, where they are destructive 

 to all crops. 



Pocket gophers do harm in many ways. They eat growing grain 

 and cover much of it Avith soil. In digging burrows .they cause 

 loss of hay by throwing up mounds Avhich prevent close mowing. 

 These mounds also injure much machine r\^ Their burrows admit 

 surface water and aid it to wash out deep gullies on sloping land. 

 By piercing dams and embankments the tunnels cause costly breaks. 

 The animals ruin gardens and injure field crops. In addition to 



this they kill trees in 

 orchards and in forest 

 plantings by gnawing 

 off the roots. 



Two practical meth- 

 ods of killing pocket 

 gophers are always 

 possible — trapping 

 and poisoning. The 

 first method is slow, 

 but very effective on 

 small areas or where 

 but few pocket go- 

 phers are present ; the 

 other is the better 

 plan on large fields and for cooperative work on adjacent farms. 

 While the ordinary steel trap may be used successfully for pocket 

 gophers, much better results can be obtained with the special traps 

 for these animals commonly on the market (fig. G). 



In irrigated districts, where water is available, flooding the land 

 will drive out the animals, and they may be killed by men and dogs. 

 Fumigation of the burrows with carbon bisulphid or with sulphur 

 smoke, while often recommended as a means of destroying pocket 

 gophers, has been found extremely uncertain and costly. 



Poison for pocket gophers. — Cut sweet potatoes or parsnips into pieces witb 

 the largest diameter less than an inch. Wash and drain 4 quarts of the cut 

 baits. Place in a metal pan, and from a i^epperbox slowly sift over the damp- 

 ened baits i ounce of powdered strychnin (alkaloid) and one-tenth as much 

 saccharin (well shaken together or ground together in a mortar), stirring 

 to distribute the poison evenly. 



Tunnels of pocket gophers, which are usually from 3 to 8 inches 

 below the surface of the ground, may be readily located by means of 

 a probe. Any blacksmith can make one by affixing a metal point 



