14 



BULLETIN 922, U. S. DEPARTMENT OF AGRICULTURE. 



from the middle to the end of June do not stop feeding until early in 

 July. The amount of foliage eaten during the postdormant period, 

 that is, after the summer inactive period, is 1.48 square inches and 

 extends over an average of 82 days, that is, not one-tenth as much 

 per day as is eaten in the predormant stage (Table VI and fig. 9). 



The amount of food consumed by the individual beetle during its 

 entire adult stage averages 4.76 square inches, 0.045 of an inch per 

 day during the feeding periods. The feeding by the beetles is there- 

 fore so slow and gradual that they seldom do an appreciable amount 

 of injury except when in unusual numbers. On the other hand, the 

 larva needs approximately 2 square inches less of foliage for its 

 development than is eaten by the adult, but of the 3.09 square inches 

 of leaf eaten by each larva, 2.48 inches are consumed during the last 

 instar, which occupies a period of 10 days or less, and the large amount 

 of foliage taken in so short a period greatly increases the liability of 

 injury. 





















JUNE 











































SEPTEMBER 







1 MAY 



JULY 



AUGUST 



OCTOBER [NOVEMBER 



DECEMBER 



Fig. 9.— Diagram showing the comparative amounts of clover foliage 

 eaten by adult beetles of the clover-leaf weevil during the different 

 months of the season. 1 



Tables IV, V, and VI give the amounts of clover foliage eaten by 

 adults and larvae. 



Table IV. — Average amounts of clover foliage eaten by adult and larva of Hypera punctata. 



Average 

 per day. 



139 



009 



001 



008 



059 



177 



06 



038 



Predormant beetle . 

 Postdormant beetle 



Larva 1st instar 



Larva 2d instar 



Larva 3d instar 



Larva 4th instar — 



Total — larva 



Total— beetle 



Average 



Average 



amount 



length 



food 



feeding 



eaten. 



period. 



Inches. 



Days. 



3.28 



23.5 



i .74 



82.0 



.019 



18.6 



.084 



10.0 



.504 



8.5 



2.480 



14.0 



3.087 



51.1 



4.02 



105.5 



1 The beetle consumes at least an equal amount of stem during this period and this could not be measured. 



1 As recorded in Table IV, at least an equal amount of stem is eaten in the fall in addition to the foliage, 

 and due consideration is taken of this fact. 



