478 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



and burned as soon as the potatoes are dug. These beetles 

 feed on several different kinds of weeds so that any weeds 

 in and near the garden should also be destroyed. 



There is also another borer, the larva of the moth Papaipema 

 nitella, that attacks potato stalks as well as tomatoes, corn, 

 and many other plants. The larva? pupate in the lower 

 part of the stalk; therefore if the old vines and weeds are 

 destroyed early in the fall this pest will usually not become 

 troublesome. 



The Potato Tuber-worm (Phthorimcea operculella). For a 

 long while this has been the most serious pest of potatoes in 

 California. In the southern states it is a common tobacco pest, 

 and has recently been reported as injuring potatoes there also. 

 The moth issues early in the spring and lays her eggs on the 

 young potato plants. The larvae bore into the stalks, often 

 killing them, but most damage is done when they make their 

 way into the ground and attack the tubers, boring irregular 

 channels in them and soon rendering the potatoes unfit for use. 

 Several generations may occur each season, the moths of the 

 later broods laying their eggs on the tubers when opportunity 

 offers. 



When plants are found to be wilting on account of the 

 presence of these larvae in the stalks they should be cut and 

 destroyed to prevent infestation by later broods. The field 

 and adjoining lands should be kept free of nightshade and 

 other related plants as this insect feeds on these also. The 

 potatoes should be exposed as little as possible, both before and 

 after digging, so that the moth may not have an opportunity 

 to lay her eggs on them. If stored potatoes are found to be 

 badly infested they may be fumigated with carbon bisulphide. 

 Four or more treatments at short intervals may be necessary 

 before all of the larvae are destroyed. 



PEAS AND BEANS 



The Pea -weevil (Bruchus pisorum). This common and 

 widespread pest has made it impracticable to grow peas on a 

 large scale in many regions. Some parts of Canada and some 



