COTTON INSECTS 409 



are both present, the former may aid the farmer by de- 

 priving the boll-weevil of its food. 



377. The cotton red-spider or rust mite (Tetranychus 

 gloveri) . The reddening of the leaves of cotton, often 

 called " red rust," is sometimes due to the attacks of a 

 minute red mite. These tiny red insects, almost micro- 

 scopic in size, may be seen on the underside of the leaves, 

 usually surrounded by a thin web. Their injury is most 

 severe in wet weather. They are easily spread by laborers 

 or teams. If they are discovered early, before many 

 plants have been attacked, the injured plants and adjacent 

 ones should be pulled and burned. Dusting with powdered 

 sulfur blown on the underside of the leaves has been recom- 

 mended. However, treatment is seldom attempted. As 

 soon as possible after being picked, the cotton plants on 

 an infested field should be deeply plowed under. 



378. Cotton lice or aphids. These are the progeny 

 of small, soft-bodied insects that suck the juices from the 

 growing tips and leaves of the very young cotton plant. 

 They are most troublesome in periods of cool weather. 

 Treatment is not attempted ; yet any insecticide that kills 

 by contact would be destructive to the insects, though 

 scarcely practicable. 



379. Cutworms (Noctuidce). The cutworms are the 

 Iarva3 or caterpillar stage of certain night-flying moths. 

 These caterpillars cut down the very young cotton plants. 

 They are most troublesome on land which has grown 

 sod or weeds the previous year. By plowing such land 

 early in the fall and planting it late in spring, the damage 

 from cutworms is reduced. While treatment is not gen- 

 erally regarded as necessary, the worms can be destroyed 



