HOW INSECTS AFFECT THE COTTON PLANT. 9 



stick as it is carried across the back of a mule ridden between the cotton rows. 

 Two rows are thus treated at once and from 15 to 20 acres can be covered by one 

 man during the early morning and evening hours which are suitable for the work. 

 It is best to apply the poison when the plants are moist with dew so that it will 

 adhere to the foliage. It is also necessary to avoid windy j)eriods. 



If the worms are in grass plots or cultivated fields adjoiimig; cotton, 

 the poisoned bait described for cutworms will be effective in keeping 

 them from the cotton. In some cases where the ground is hard, 

 with little vegetation, the use of heavy roUers or brush wiU be of 

 advantage in crushing the worms. Deep furrows aroujid the field 

 will catch many worms moving into a field and in these they may be 

 crushed. 



When they are full grown they enter the soil and change to pupae. 

 A shallow cultivation by disking or with a spring-tooth harrow at 

 this time is very effective, as it wiU kiU many pupae and expose others 

 to the heat of the sun. 



INJURIES TO THE GROWING TIP. 



The growmg tip of cotton frec^uently is injured by insects whicli 

 make their principal attack on other parts. The boU weevils in the 

 spring frequently injure the tennhial bud when they emerge from 

 liibernation before the squares form. Grassworms, cutworms, and 

 grasshoppers do similar injury. Frequently small "worms" which 

 make a web around the leaf or bud are to be found. These belong to 



Fig. 7.— Cowpearpod weevil: a, Adult weevil; b, larva, side view; c, head of same, 

 front view; d, pupa, viewed from below. Much enlarged. (Chittenden.) 



several different genera' of moths and are not often of grave impor- 

 tance. As they are usually hisects which normally attack some weed, 

 another argument for weed control and faU plowing is afforded. 



The cowpea-pod weevil ^ (fig. 7) frequently attacks young cotton 

 and causes injury by pmicturhig the terminal bud. These attacks 

 usually occur when cotton follows cowpeas. 



1 Platynota, Loxostege, etc. ^ Chalcodermus aeneus Boh. 



8608°— 17— Bull. 890 — ^2 



