CHAPTER XIV 

 INSECT PESTS 



THE BANANA WEEVIL BORER (Sphenophorus sordidus) 



THIS borer, which causes so much damage to bananas, 

 belongs to the family of weevils, the chief feature of which 

 is the rostrum formed by the continuation of the fore part 

 of the head. It is nearly related to the weevil borer of 

 the sugar-cane (S. sericeus), but is smaller and of a more 

 uniform dark colour. The annual loss caused in Fiji * by 

 the ravages of this insect probably amounts to many 

 thousands of pounds. It is a most difficult pest to deal 

 with owing to its habits, the whole life-history being spent 

 in the bulb or in the soil. 



Effect on the Plant. Young suckers attacked by the 

 borer wither and quickly die. The first indication that a 

 sucker is attacked is the death of the young leaves while 

 still unrolled. The bulb, when cut open, is found to be 

 riddled by the larvae. The plants attacked at a later stage 

 in their growth have the appearance of healthy plants, and 

 when a certain stage in the growth has been reached they 

 produce a good bunch, and the presence of the borer does 

 not seem to have affected it. The adult weevils are 

 abundant in the soil about the roots, and also are often 

 found sheltering under dead leaves at the base of the 

 stem. 



Habits and Life-history. The eggs have not yet been 

 discovered, but it is believed that they are deposited 

 singly upon the base of the stem about half an inch above 



* '* Report on Economic Entomology," by F, P. Jepson, Dept. of 

 Agric., Fiji, 1911. 



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