24 AN ECONOMIC STUDY OF FIELD MICE. 



Field mice injure early peas and other vegetables growing in open 

 grounds, and pine mice often destroy potatoes in the ground. In the 

 fall vegetables piled on the ground or stored in pits are liable to 

 attacks. Among these are potatoes, beets, turnips, carrots, parsnips, 

 cabbage, sweet potatoes, and especially celer} 7 . Apples, pears, and 

 other fruits are eaten also. 



In parts of eastern Maryland pine mice have recently (1907) been 

 quite destructive to melon and cantaloupe crops. The animals 

 destroy the seed and eat the roots of the plants during the growing 

 season. The injury was greatest on sandy lands which had not been 

 plowed before planting, but had been smoothed with a drag, leaving 

 the mouse tunnels below undisturbed. In some fields seed had been 

 planted three times, but by the middle of July all hope of a crop had 

 been abandoned. 



DAMAGE TO SMALL FRFITS. 



Blackberries, raspberries, grapes, currants, gooseberries, and straw- 

 berries are often badly damaged by field mice, and when the animals 

 are abundant whole plantations are ruined. Strawberries are espe- 

 cially liable to injury because of winter mulching and also because 

 the plants themselves furnish excellent food and shelter for the 

 animals. 



Fallen leaves in autumn and snow in winter drift and collect along 

 rows of blackberry, raspberry, gooseberry, and currant bushes and 

 furnish cover for mice, which work along the rows and girdle the 

 green steins: and when dead canes are left uncut and weeds are per- 

 mitted to grow up among them, the resulting tangle adds much to 

 the liability of attack. Winter mulching of small fruits also in- 

 creases the danger, and if practiced the utmost care should be taken 

 to clean surrounding areas. 



DAMAGE TO XFRSERT STOCK. 



In many sections of the United States and southern Canada nursery" 

 stock is injured by field mice. The actual loss varies from year to 

 year and is difficult to estimate. Occasionally the havoc has been so 

 complete that few marketable trees remained. It was estimated that 

 during the winter of 1901-2, nurserymen in the vicinity of Kochester, 

 X. Y., sustained losses amounting to $100,000.° 



Damage to standing nursery stock is done usually under cover of 

 snow, and hence is greatest in seasons of deep snows that remain long 

 upon the ground. In addition to girdling trees above the surface 

 of the ground, meadow mice sometimes burrow beside the trunk and 

 attack the roots (PL III. fio-. 2). Pine mice usually begin their 



« New York Sun, April 27, 1902. 



