22 



FARMERS BULLETIN 



Fig. 26.— Cotton boll showing 

 punctures of a cotton leaf- 

 bug, Adelphocoris rapidu.t. 

 (Sanderson.) 



feed on the petals and eat the pistil and stamens. In case of injury 

 to the pistil the boll frequently fails to mature. These msects in 

 their immature stages prey on other insects and are beneficial. 



LEAF BEETLES. 



A number of small leaf beetles — some brown, some blue, some 

 green, or striped with yellow — -occur on cotton squares and feed on 

 the bracts or sometimes eat the leaves of cot- 

 ton. They are native to weeds around the 

 fields, and are seldom important. 



INJURIES TO THE STALK AND ROOTS. 



COTTON WIREWORMS. 



In South Carolina much injury is done to 

 the roots of cotton by wireworms^ (see fig. 31). 

 The adidts of these worms are the well known 

 click-beetles so abundant at the flowers and 

 squares of cotton. They are controlled best 

 by using a crop rotation in which cotton fol- 

 lows oats and corn follows cotton. The oats 

 stubble should remain on the land until Sep- 

 tember 15. After this time it is weU to pre- 

 pare the land and plant a winter cover crop. 

 The cover crop should be supplemented with stable manure, swamp 

 muck, or lime, as it is necessary to build up soil infested by wireworms. 



CORN ROOT-APHIS ON COTTON.= 



Especially in South Carolina the cot- 

 ton is attacked at the roots by the root- 

 aphis of corn. This insect is similar in 

 appearance to the cotton aphis but con- 

 fines its attacks to the taproot of cotton. 

 The best control is a three-year system 

 of rotation in which cotton does not 

 foUow either corn or cotton. Small 

 grain or cowpeas should precede cotton 

 on badly infested lands. The three-year 

 rotation of oats and co^V]:)eas, cotton, and 

 corn has proved su(;cessful. It is of 

 great value to have a winter cover crop 

 on infested lands at all times, as it ])re- 

 vents the winter food })lants of the cot ton 

 root-aphis from growing ui)on tlie land. 



1 Monocrcpidius vespertinus Fabricius, Horistonotus uhlerii Horn, and related species. For an account of 

 these and other species see Farmers' Bulletins 725 and 733. 

 » Aphis maidiradicis Forbes. 



Fig. 27.— l,eaf-footed Dlant-bug (Leptoglos- 

 sus phijllopus) twice natural size. (Hub- 

 l>ard.) 



