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Bulletin 87 



group notoriously favored by hot, dry weather. In the Southeast- 

 ern states the influence of weather on breeding activity was found 

 to be very noticeable. Hot, dry conditions favored rapid develop- 

 ment while cool, wet weather retarded it, the rate of egg laying 



varying from none to twenty per day 

 according to temperature. 



In view of the possibility of this 

 spider appearing in Arizona cotton 

 fields sooner or later, preventive meas- 

 ures should be closely observed. Vio- 

 let and strawberry plants and the 

 Dorothy Perkins rose are food plants 

 which are very likely to be a means of 

 spreading and maintaining the pest. 

 Not all beds or specimens of these food 

 plants in the Salt River Valley are in- 

 fested with the red spider. It is also 

 probably true that there are many 

 other kinds of plants which are sub- 

 ject to infestation and more or less 

 dangerous. It is advisable, however, 

 for cotton growers either not to per- 

 mit the plants named to grow near 

 cotton fields, or to examine them care- 

 fully from time to time to detect the 

 first infestation should the red spider 

 appear. Weeds or other plants supposed to be infested with the 

 red spider should be submitted to the Office of the State Ento- 

 mologist, Phoenix, or the Department of Entomology, College of 

 Agriculture, Tucson, for examination. When preventive measures 

 have not been given proper attention or have failed to protect the 

 cotton field, spraying with potassium sulphide, lime sulfur solution, 

 kerosene emulsion, or flour paste solution is recommended. Flow- 

 ers of sulfur and "Atomic Sulfur", which are efifective against most 

 species of red spider, have not proved effective against this one. 



Fig. 29 — The two spotted red 

 spider (greatly enlarged). 



OTHER COTTON PESTS 



Of the pests discussed in the foregoing pages all except the Mex- 

 ican cotton boll weevil and the pink bollworm occur in Arizona. A 

 very close relative of the Mexican boll weevil, however, is found 

 in certain mountain ranges of the Southern part of the State. In 

 addition there are over twenty other species of insects known to 



