18 THE RED SPIDER ON COTTON. 



late as June 20 seem to have largely escaped the infestation which 

 was so general at that locality. Late planting, however, is almost 

 universally objectionable to the farmer, since iti ordinary seasons it 

 results in a reduction of the yield. 



Rotation. — In an effort to test the rotational value of other crops, 

 numerous field crops have been planted in or near infested areas. 

 In addition, frequent examinations have been made of a great many 

 garden and vegetable crops in infested localities. Besides cotton, 

 red spiders are known to occur not at all uncommonly upon the fol- 

 lowing field crops: CoAvpeas, clover, corn, hops, and watermelon. 

 They are also found frequently on the following garden crops : Peas, 

 beans, onion, tomato, lettuce, okra, turnip, mustard, squash, beet, 

 sweet potato, and strawberry. A really acute infestation on corn 

 (as above recorded) was seen at the height of the past season (1912). 

 Cowpeas are particularly attractive to the pest, and sweet potatoes 

 have been noted to be badly infested. Should an immune crop be 

 found and employed, it is extremely probable that the pest would 

 reinvade the fields upon the return to cotton culture with as great 

 ease and quickness as it has done during any previous season, provid- 

 ing the sources of infestation were yet at hand. Rotation, then, does 

 not promise to contribute toward the solution of the problem. 



Eljects of fertilizers. — A rather elaborate series of tests with fer- 

 tilizers has been conducted in an attempt to determine whether the 

 various applications assisted cotton to withstand the injurious effects 

 of infestation. Since almost no infestation appeared in these test 

 plats it was impossible to deduce positive conclusions. 



REPRESSION. 



We have just discussed cultural measures which may help to pre- 

 vent infestation. We will now consider what may be done to combat 

 the pest when it has alread}^ gained entrance to a field. 



The Avriter believes in prevention rather than cure, in the case of 

 the red spider. Wlien once well established in a cotton field the 

 pest is a most difficult one to wipe out. That it is possible, however, 

 to eradicate the pest from infested fields lias been demonstrated be- 

 yond doubt, but in many cases the task is so tedious that only the 

 most determined farmers will undergo the effort necessary to accom- 

 plish the extermination. 



Removal of infested plants. — The experiment has been thoroughly 

 tested of pulling up and destroying the first few plants which show 

 infestation. In such cases the operation was repeated several times. 

 Great care was observed in locating every plant showing the charac- 

 teristic red spots, and these were carefully taken from the field and 

 burned. If infestation has not advanced far, this treatment is 

 usually satisfactory, and a red-spider invasion often may be " nipped 

 in the bud " and entirelv eradicated. 



