Bulletin 340] CONTROL OF THE POCKET GOPHER 341 



the earth as into a burrow. In cultivated fields the dry surface soil 

 tends to ruti in and to fill up the hole made by the probe. 



Gophers are most likely to gnaw or girdle orchard trees during 

 late summer after the surface of the ground has become dry and green 

 vegetation is scarce. Thus at the very season when the gopher is doing 

 the most damage, and hence his speedy destruction is most to be 

 desired, the probing method is of little use and the rancher must then 

 dig down to the main runways in order to set traps or place poisoned 

 vegetable baits, which latter are especially effective at this time of year 

 on account of the scarcity of green vegetation. 



The best time to use the probe is just after the first good winter 

 rains and before alfilaria ("filaree") or other green vegetation becomes 

 abundant. The rancher should poison his land thoroughly at this 

 time and thus kill the bulk of his gophers with a minimum of effort 

 and expense. On account of the abundant and continuous food 

 supply, alfalfa fields are more difficult to treat effectively than orch- 

 ards or open fields. 



When several acres are to be poisoned at one time a large number 

 of baits are required. These may be prepared according to the follow- 

 ing government formula : 



Sweet potatoes, parsnips, or carrots 4 quarts 



Flour paste % pint 



Strychnine alkaloid, powdered % ounce 



Saccharin %2 ounce 



The vegetables should be cut into Y^^-ineh cubes. The cubes must be 

 large enough that the gopher is unable to pocket them. Failing in 

 this, he will usually begin to eat the poisoned bait on the spot. The 

 strychnine and saccharin should be stirred into the cooked flour paste. 

 It is at times difficult to secure saccharin, and in that case a couple 

 of tablespoonfuls of heavy corn sjTup may be substituted. Gophers 

 appear to be less sensitive than ground squirrels to the bitter taste of 

 strychnine ; perhaps because they are more accustomed to eating bitter 

 roots. After the sweetened, poisoned paste has been prepared, it should 

 be poured over the vegetable cubes, which should then be stirred until 

 each piece is thinly coated with it. The poisoned baits are now ready 

 for use and should for safety be kept in a covered bucket plainly 

 marked poison. 



The probe (see fig. 1) can readily be made by any blacksmith from 

 a two-foot section of %-ineh round steel. The metal part of the probe 

 should be pointed at the lower end and bent near the upper end to 

 form a foot-rest which may be stepped on by the operator and thus 



