INSECTS INJURIOUS TO THE STRAWBERRY 393 



undoubtedly laid on the crown between the bases of the leaves 

 in late spring. The larvae develop in the crowns and become full 

 grown by midsummer or August when they pupate in the cavities 

 formed and the adult beetles emerge in late summer and fall. 

 There seems to be but one generation a year. Old plants are 

 worst injured, and runners formed late in the season are usually 

 free from the pest, as eggs are probably not laid after June. 



Control. Frequent rotation, plowing up the bed after one 

 or two crops, will largely prevent the pest becoming established. 

 Where the insect is well-established in old beds, it will be well 

 to secure plants from beds known to be free from the pest and 

 to plant new beds at some distance from the old ones. Infested 

 beds should have the plants plowed out and raked up and burned 

 as soon as possible after the fruit is harvested and before August. 

 Owing to the fortunate fact that the beetle cannot fly from field 

 to field, if the above measures are consistently carried out 

 there should be no trouble in controlling the injury. 



Strawberry Rootworms * 



The larvae of three species of common leaf-beetles often feed 

 upon the roots of the strawberry and are easily mistaken for the 

 crown-borer or for small white grubs. They may be distinguished 

 from the former by having three pairs of small thoracic legs just 

 back of the head, and from the latter by their being much thicker. 

 These rootworms are from one-eighth to one-sixth inch long, 

 whitish, with brownish heads, and usually feed on the roots 

 externally, though sometimes boring into them or the crown. 

 Dr. Forbes * has indicated the structural differences by which 

 they may be separated and shows that their life histories are 

 quite dissimilar. "The larva of Colaspis appears early in the 

 season, and does its mischief chiefly in the months of April and 

 May, the beetles beginning to emerge in June. That the eggs 

 are laid in the preceding year is highly probable, in which case 

 the species hibernates in the egg. Typophorus, on the other 

 hand, certainly passes the winter as an adult, doubtless laying 

 its eggs in spring, and making its principal attacks upon the 

 plants in June and July, the beetles emerging in the latter part of 



* Typophorus canellus Fab., Colaspis brunnea Fab., Graphops pubescens 

 Mels. Family Chrysomelidas. See Forbes, I.e., p. 150. 



