RED SPIDER ON COTTON AND HOW TO CONTROL IT. 



13 



Where a continuous area of infestation occurs in a large field, it is 

 often advisable to plow up the worst affected portion and spray the 

 rest of the infested area in order to save the balance of the field. The 

 stalks should be quickly piled up and burned with the aid of straw 

 or light trash. Such a severe measure should be resorted to in ex- 

 treme cases only, and the planter concerned must be the judge of 

 its advisabihty. 



INSECTICIDES. 



Out of 75 different spray combinations tested agamst the red 

 3pider on cotton the following have been found to be thoroughly 

 satisfactory: (1) Potassium sulphid (1 ounce to 2 gallons water); 



Fig. 9.— Bucket spray pump. (Quaintance.) 



(2) lime-sulphur (homemade or commercial); (3) kerosene emul- 

 sion (prepared according to usual formula); (4) flour-paste solu- 

 tion (1 gallon stock paste to 12 gallons water). Spraying for the 

 red spider is effective if it is done with extreme care. The fore- 

 going sprays, when properly applied, kill all mites, but a second 

 spraying, one weeJc later, is necessary to hill the individuals that were 

 in the egg stage at the time of the first spraying. Arsenical sprays are 

 of no use against red spiders. 



SPRAYING OUTFITS. 



The sort of outfit to be used for spraymg the red spider on cotton 

 depends mainly on the extent of the occurrence. Many prefer to use 

 a small tin atomizer when only a score or so of plants are to be 

 treated. These instruments are very economical of licjuid and throw 

 a very fine, vapory spray which reaches all parts of the plants. The 

 bucket pump (fig. 9) and knapsack pmnp (fig. 10) come mto use in 

 cases of considerable scattered infestation, or for treatment of a few 



