Insect Pi-sts of Interest to Cotton Growers 



183 



southern Arizona and from observations so far made it does not 

 seem likely that it will ever prove to be a serious cotton pest in the 

 arid Southwest. The tendency seems to be for Egyptian cotton 

 plants to grow too rank, and in most cases the partial defoliation 

 which results from an attack of the cotton leaf worm late in the 

 season will prove a decided benefit in maturing the cotton crop. If, 

 however, the insect should make its appearance earlier than usual 

 in the season, and consequently multiply to injurious numbers and 

 threaten serious injury to the crop, it may be poisoned by dusting 

 the plants with Paris green, arsenate of lead, or calcium arsenate as 

 is still done occasionally in parts of the eastern cotton belt. 



THE S.\LT MAKSII CATERPILLAR 



The salt marsh caterpillar (Estigmcnc acraca Dru) appears every 

 year in greater or less numbers in the cotton fields in southern 



Fig. 10 — Salt marsh caterpiMar. a. Female moth; b. half^own 

 larva; c. mature larva, lateral view; d. egg mass. 



Arizona. It has many food plants in addition to cotton and may be 

 found multiplying on trees, field crops or weeds. In the Salt River 

 Valley it sometimes does considerable damage to the bean crop. 

 Among the weeds probably its favorite food plant is one known 

 as the yellow flowered ground cherry (Physalis angulata variety 

 linkiana). In the only instance when the salt marsh caterpillars were 



