j^_ 10.99. Issued March t>, 190H. 



818 aited States Department of Agriculture, 



C578 

 ENT 



BUREAU OF ENTOMOLOGY. 

 L. O. HOWARD, Entomologist and Chief of Bureau. 



THE NUT WEEVILS.' 



By F. H. Chittknden, Sc D., 

 Eiitoniologid in Charge of BrenUng Exjieriments. 



Introduction. 



Nut-growing- in the United States would be a much more profitable 

 industry were it not for the insects which inhabit the kernels, render- 

 ing them unfit for food. This is especially true of the chestnut and 

 chinquapin and to a lesser extent of pecan, hickory, and hazel nuts ; 

 while othei"S, which include butternuts, walnuts, and almonds, suffer 

 little or no injury from this source. Considerable diminution in the 

 yield of many forms of nuts is also caused by the inroads of insect 

 larvae in the growing husks. Examples of the first class are the chest- 

 nut " worms " or Aveevils; of the second, the husk-worms and walnut 

 curculio. The present paper will be restricted to a consideration of 

 the weevils. 



The chestnut crop suffers the greatest loss, and the chief depredators 

 are the grub-like " worms " or larva? with which everyone is too dis- 

 tressingly familiar. These larvae develop with the nuts, so that those 

 which first attain maturity are ready to leave and enter the ground 

 nearly as soon as the nuts 



are gathered; others re- v^'^l^f^*. -^K^ 



main in the nuts some 

 weeks later; so it fre- ,^y^ -^^^ -^ ^«^ *, 

 quently happens that 11 -t? ^r ^^ H / 

 when nuts are p fl c k e d 

 for shipment in bags or 



barrels, some nuts which Ym. l. -chestnuts showing exit holes of chestnut weevil 

 were apparentlv sound larvs. Enlarged one-fourth (author's illustration). 



when shipped are found, on reaching their destination, with one or 

 more holes in their shells (fig. 1), while the repulsive grubs crawl 

 about at the bottom of the receptacle. How to cope with these weevils 

 has long been a most vexatious i)roblem. 



The Chestnut Weevils. 

 In comparatively recent years chestnut culture has assumed consid- 

 erable proportions, and has taken a new impetus since the extensive 

 introduction and development of Japanese and European varieties. 

 These are grafted on American seedlings or native stocks, and thus 

 manv valueless trees on equally unpromising soil are converted into 



"Reprinted from Yearbook of the Department of Agriculture for 11>04, pp. 

 299-310. Pis. XXVII I-XXX, text figs. 17-26. 



[Cir. 09] 



