KODENTS AND MOLES AS PESTS IN BULB PLANTINGS 



13 



determined by the extent of the infestation. Field mice feed mostly 

 under cover, so the bait must be placed accordingly. This method 

 of placement is effective in good weather and prevents needless 

 destruction of other forms of life. 



In localities where the rainfall is heavy or continuous over long 

 periods it may be necessary to use small shelters or caches for 

 the baits. A convenient shelter is an old tin can (fig. 8) with the 

 top partly cut out and so bent as to protect the opening of the 

 can and at the same time permit the mice to enter. Small drain- 

 tiles or inverted V-shaped troughs make satisfactory shelters. Tubes 

 9 inches long, 2 inches in diameter, made from sheets of medium- 

 weight asphalt building paper, cut to 9 bj 7 14 inches, may also 

 be used. The grain baits may be put in or under these shelters, 

 which are placed along the mouse coverts or at burrow openings 

 in the bulb plantings. The grain left in these caches will mold, 

 so instead of baiting too heavily at a time, it is better to use small 

 quantities of bait and replenish them frequently. The baits may 

 also be placed within the runways of moles and pocket gophers 



by using a small 

 probe to make a 

 hole. Through this 

 the bait is dropped, 

 and then the open- 

 ing is carefully 

 closed. 



Perhaps the chief 

 interference by the 

 common brown rat 

 with the bulb in- 

 dustry is in its de- 

 s t r u c t i o n of the 

 bulbs in storage, 

 whether in build- 

 ings or buried in 

 the ground. Rodent-proof methods in the construction of storage 

 facilities are the only absolute safeguard against the rat, though 

 infestations can be reduced by systematic poisoning work. Detailed 

 information on rat control is given in Farmers' Bulletin No. 1533; 



Figure 8. — Simple bait shelter for field and orchard mice 

 made of an ordinary tin can, which protects the bait from 

 the weather and makes it accessible to mice only. 



and on rat proofing buildings and premises in Farmers 

 No. 1638. 



Bulletin 



POCKET GOPHERS 



Signs of the pocket gopher's presence about gardens or fields are 

 the mounds of earth it heaps upon the surface from underground 

 excavations made in search of roots and bulbs. Unusually large 

 mounds or numbers of them in close association may indicate food- 

 storage chambers and nests in the near vicinity. Often, however, 

 the only signs of a pocket gopher's activity for a time are incon- 

 spicuous traces of fresh-loose earth in cracks of the soil or holes 

 where the feet of farm animals have broken through. Unlike mole- 

 hills, which are built up by successive upheavals through the center 

 of the pile, pocket gopher mounds are accumulations of fine, loose 



