r. S. D. A., B. K. Bui. 64. I'tirt II. Issued April 2, 1907. 



SOME MISCELLANEOUS RESULTS OF THE WORK OF 

 THE BUREAU OF ENTOMOLOGY-IX. 



NOTES ON THE ECONOMIC IMPORTANCE OF SOWBUGS. 



By W. DwiGiiT Pierce, 

 tSpecial Field Af/e)if. 



Having been detailed to investigate certain injuries attributed to 

 soAvbugs, the writer presents the following notes concerning the life 

 history and habits of three species of these isopods, namely, Armadil- 

 lidiiim vulgnre Latr., PorceU'w Ice vis Latr., and Metojyonorthns pmd- 

 TiosKS Brandt. The first species, at least, is capable of doing con- 

 siderable injury to garden crops, flower gardens, vines, and field 

 crops in the vicinity of buildings, although it is also found to be a 

 valuable scavenger. The scavenger habit, however, makes it an unde- 

 sirable intruder in the house owing to the possibility that it may 



convev disease. 



ARMADILLIDITJM VULGARE Latr. 



The sowbug AnnadUlidiion ruhjare' l^'^iv. is commonly known as 

 the " pill-bug," on account of its habit of rolling into a ball whenever 

 disturbed. Ordinarily it is found only in the vicinity of habitations, 

 in dark, damp places, such as woodsheds and cellars, under boards 

 and rubbish, and around wells, cisterns, and water barrels. The open 

 foundations under houses in the South give very favorable locations 

 for breeding. 



For several years the Department of Agriculture has received 

 reports of injury from sowbugs to one or another crop in various 

 parts of Texas. The sowbugs seem to have been on the increase from 

 year to year. In 1905 the spring rains, although at times occasioning 

 a natural check to these pests, brought about a series of conditions 

 favorable to a rapid increase in their numbers. Moisture is a requisite 

 to their life, and it also seems that vegetation is a standard article of 

 food. The bad conditions of the ground throughout Texas during 

 that year made all crops very late, so that by the time the succulent 

 cotton and garden crops were coming up the new l)roods of young 

 sowbugs were everywhere engaged in finding delicate, tender food. 



15 



