d36 MANUAL OF VEGETABLE-GARDEN INSECTS 



two inches in the s:)il. The eggs hatch in abnnt three weeks 

 or a httle less, depending on the temperatnre, and the young 

 kirva begins feeding on the roots. Although the larviie have 

 only been found on hop roots, they undoubtedly feed on other 

 plants. They become full-grown in about three weeks. They 

 are then about J inch in length, white, with the head, thoracic 

 shield and anal plate darker. After reaching maturity, the 

 larva becomes somewhat shorter and thicker and rests in a 

 dormant ct)ndition for nearly two weeks before transforming 

 to the white pupa. Pupation takes place in the soil but not 

 in an earthen cell. The pupal period averages about sixteen 

 days. There are two generations annually. From eggs de- 

 posited in the early spring by over-wintered beetles, a new 

 brood of adults is produced the last of May or early in June, 

 and another brood appears the last of July or the first of August. 

 The latter go into hibernation with the advent of cool weather. 



References 



U. S. Bur. Ent. Bull. 66, pp. 71-92. 1909. 

 U. S. Bur. Ent. Bull. 82, pp. 33-58. 1910. 



Means of Controlling Flea-Beetles 



It is usually difficult to prevent injury by flea-beetles because 

 the attack is made by the adults, most of which feed only 

 slightly on the surface of the leaf and are more or less resistant 

 to poisons. They also avoid the poison and attack the leaves 

 where the spray has not been applied. The attack is usually 

 most severe on young plants early in the season when the 

 beetles are most voracious after their long winter's fast and 

 when the plants are least able to withstand injury. Contact 

 insecticides have been found of little value because of the 

 difficulty of hitting the insects, since the beetles jump from the 

 plants at the slightest alarm only to return when the danger 



