THE ALFALFA WEEVIL 



By George I. Reeves 

 Entomological Assistant, Bureau of Entomology, U. S. Dept. of Agriculture. 



The damage which the alfalfa weevil does each year can be esti- 

 mated by millions of dollars. So many of the little green larvae 

 feed upon the leaves in May and June that the plants soon fail to 

 make headway against the attack and then are gradually eaten to 

 rags. If the field is well cultivated, fertile, and well watered and 

 drained, the first crop may, in favorable seasons, reach maturity 

 without much loss, but usually it begins to look white as if frost bitten 

 a week or more before it is ready to cut, and then it must be harvested 

 at once or be lost. Severe as is the effect upon the first cr6p, it only 

 begins the trouble, for the attack upon the second crop is so severe 

 as to amount to total loss. The larvae which feed upon the first 

 crop while it is in the field are forced to live upon the stubble after 

 haying, and although a great number of them are killed by the change 

 from the cool, moist shelter of the growing alfalfa, to the blistering 

 heat of the stubble-field, enough of them survive to cover the little 

 foliage which remains, eat the buds faster than the latter can grow, 

 and prevent all growth until they have finished their feeding period, 

 which means until the time when the second crop should 'have been 

 ready to cut. Their work ends here, but it has cost the farmer half 

 his annual yield of alfalfa hay. The insect spends the rest of the 

 year in the pupal and adult stages, during which it is harmless, except 

 that it is preparing to lay eggs in the dry stems on the ground and 

 the green standing stems from which will hatch the larvae to attack 

 the crop of the following year. This steady succession of severe at- 

 tacks, year after year with only one exception in the 12 years' since 

 the weevil was first discovered in Utah, is one of the most serious 

 features of the alfalfa weevil situation. The regions which have 

 been invaded by the pest are no longer able to produce alfalfa hay 

 in excess of their own needs, but on the contrary, must import it. 

 Nothing more need be said of the importance of this' pest to the west- 

 em states, whose agriculture is based largely upon the alfalfa crop. 



The steady recurrence of the weevil attack, while it makes the 

 damage greater, en the other hand gives greater opportunities for its 



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