POTATO PESTS 



1727 



Fig. 1. Potato Tuber Moth (Phthorimaea 

 operculella Zeller). 1, cocoons containing 

 chrysalids ; 2, larvae; 3, bare chrysaiids. 

 (Enlarged.) — Essig 



grown they are about one inch long. The 

 cocoon is spun of fine white web, the 

 chrysalis being light brown in color and 

 about three-eighths of an inch in length. 

 The wings of the adults are decidedly 

 gray in color with the bodies silvery. 

 They are about one inch long. 



Life History 



The small pearly-white eggs are laid on 

 the stems of growing potato plants or 

 upon exposed tubers in early summer, or 

 upon the tubers at digging time. Within 

 15 days they hatch into caterpillars, 

 which feed upon the leaves, stems or 

 tubers, or only upon the latter when they 

 are stored in bins. It requires from three 

 to five weeks to mature, when it seeks a 

 shaltered place and spins a cocoon, in 

 which to pupate. During the winter the 

 pupal period may occupy several months, 

 but in the summer and fall from 14 to 20 

 days are required. The adults are night 



Fig. 2. Adults of the Potato Tuber Moth 

 (Phthorimaea operculella Zeller) enlarged 

 several times. (Essig. M. B. Cal. Hort. 

 Com.) 



flyers and are especially abundant in the 

 fall, particularly when early potatoes are 

 dug. If the tubers are exposed over night 

 the females lose no opportunity to deposit 

 their many eggs, generally over all of 

 them, so as to make a serious infestation. 

 The adults live but a few days. 



Distribution 



Throughout the central and southern 

 parts of California, in Florida, North and 

 South Carolina and Virginia. 



Food Plants 



Potatoes, tobacco, nightshade, and cat- 

 tails are attacked. 



Control 



All host plants should be kept from 

 growing in or around the potato fields. 

 Deep planting and hilling should be prac- 

 ticed to prevent access to the tubers. The 

 potatoes should be dug as early as pos- 

 sible and not allowed to remain in the 

 fields over night, unless sacked. In places 

 of general infestations the tubers may be 

 thoroughly disinfected before storing, by 

 soaking them in water for 36 hours. In 

 the storage bins, two pounds of carbon bi- 

 sulfid to every 1,000 cubic feet of air space 

 will prevent injury, provided this is done 

 four or five times, or as often as adult 



moths appear. 



E. O. Essig 



Sand or Jerusalem Cricket 



Stenopelmatiis irregularis Scudd. 



General Ai)i)earance 



The adults never have wings and are 



