162 



THE MONTHLY BULLETIN. 



THE SMALL SWEET POTATO WEEVIL. 



Order — Coleoptera. 



(Cr!jt>forli!/ii(hiis h(tf(it(r Waterh. 1 



By L. A. Whitney. 



Family — Curculionidae 



is subject, namely, Cryptorlnjnclius 



During the past three years the writer has had the opportunity of 

 observing at first hand one of the woi-st pests to which the sweet potato 



batata-. This insect fortunately 

 has not become established in 

 California, although it is taken 

 in ([uarantine repeatedly. In 

 some shipments inspected fully 

 50 per cent of the tubers ex- 

 amined have been riddled by 

 the larva? of this insect, as the 

 accompanying photographs 

 will show. The consignment 

 under consideration (Fig. 24) 

 arrived from Honolulu, T. H., 

 per steamship Lurline July 

 16, 1918, and consisted of 50 

 crates. At the time the in- 

 spection was made the writer, 

 finding several potatoes badly 

 Infested, decided to examine 

 the contents of the entire box 

 and ascertain just how exten- 

 sive the infestation really was. 

 It proved to be so great that a 

 photographic record was made 

 and the illustration makes a 

 very graphic presentation of 

 the extent to which the same 

 had developed. 



The presence of this pest, 

 like its two collaborators, 

 Ompliisa anastamosalis and 

 Cylas formicarius, is almost 

 impossi]:)le to detect from ex- 

 ternal indications, as the larvtt enter the fuller while very small and 

 the only evidence of their presence would be a slight exudation of gum 

 or juice of the potato, which is easily brushed or rubbed off. Accord- 

 in^dy the onlv certain method of determining infestation is a thorough 

 examination with a knife, which means in most cases the destruction 

 of the potato. 



Fig. :i4. — tfhowins the percentupe of infested 

 and sound tubers in one box. Portion in- 

 fested witli CnnJtorhimchus batatw on the 

 left, sound portion on the right. (Photo 

 by Chatterley. ) 



