INSECTS INJURIOUS TO CLOVER AND ALFALFA 197 



and somewhat curved as shown in Fig. 165. They attack the 

 young leaves and crown so that a badly infested field will not get 

 over six inches high; too short to mow. The Iarva3 are most 

 abundant in May and decrease through June. When full grown 

 the larvae crawl or drop to the ground and spin their cocoons 

 in the dead leaves or rubbish. The cocoon is globular and com- 

 posed of a network of rather coarse white threads, Fig. 165. 

 In it the larva transforms to a pupa, which stage lasts from 

 one to two weeks, when the adult beetle emerges. 



From early to midsummer the beetles become more and more 

 abundant, and not only feed on the fresh growth, but attack the 

 bark of the stems so that where excessively abundant they totally 

 destroy the second crop. 



"The entire life of the insect, from the deposition of the egg 

 to the emergence of the adult, may be anywhere from forty to 

 seventy days, while the beetle itself may live, including the winter, 

 from ten to fourteen months." Webster. 



Inasmuch as literally millions of the beetles have been gath- 

 ered by machines from a single acre, and as the beetles have been 

 found in considerable numbers on freight and passenger trains, 

 it is highly probable that the pest will be spread by the several 

 trunk-lines of railroad which pass through the infested region, as 

 in many places alfalfa has escaped from fields and grows as a 

 weed along the railway tracks. It is, therefore, highly important 

 that alfalfa growers be on their guard against this pest and take 

 prompt measures for its destruction wherever it may gain a 

 foothold. The weevils also spread rapidly by flying in spring 

 and summer, which migration is aided by the winds. They may 

 also be spread in articles shipped from an infested region and 

 on wagons or automobiles. 



Control. The methods of control have not, as yet, been 

 satisfactorily determined, though the entomologist of the Utah 

 Agricultural Experiment Station, E. G. Titus, from whose report 

 the following summary is taken, has made extensive experiments 

 with various methods. 



Old alfalfa fields are always worst injured, and fields should 

 not be left down in alfalfa over about seven years. Thorough 

 disking in the early spring has proved to be one of the essential 

 factors in securing a good crop, as it increases the stand and 



