100 THE BANANA 



the level of the soil, as the burrows of the larvae can be 

 traced from minute spots there. The burrows widen in their 

 course as the larvae progress, and terminate in a pouch 

 near the surface in which the larva pupates. The larval 

 period lasts about twenty days. A period of from six 

 to eight days from the time of pupation elapses before the 

 emergence of the adult. The adults remain in the soil for 

 some time, and then come to the surface to deposit their 

 eggs. The length of life of the adult is not known ; they 

 have been kept in dry earth without food for three months. 

 In all probability the borer continues to breed all the year 

 round, so long as there is a plentiful food supply. A 

 plantation lying fallow for a year would cause the beetle 

 either to migrate in search of food or to be starved. The 

 planting of crops which the borer would not attack upon 

 land previously planted with bananas would have the 

 same effect. 



Larva. The larva is a fleshy, footless, cream-coloured 

 grub measuring 20 mm.* in length and 8 mm. in breadth. 

 The head is light brown in colour, while the cervical shield 

 is pale yellow. 



Adult. The adult beetle measures 14 mm. in length 

 and 4 mm. in breadth. The colour is black. The rostrum 

 is 4 mm. long. The antennae are elbowed. The elytra, or 

 hard shielding wings, are marked with longitudinal grooves. 



Prevention and Remedies. The banana borer is a very 

 difficult pest to deal with, and it is believed that the only 

 effectual means of dealing with it is by the agency of 

 natural enemies, if they can be found. There is no doubt 

 that a system of rotation of crops would do much to 

 diminish the number of borers on a plantation, as they 

 would in this event either die from starvation or have to 

 seek elsewhere for food. Clean cultivation and the 

 destruction of all old banana stems and roots would 

 eliminate favourite breeding- places. 



Experiments have shown that in captivity adults will 

 not live in soil without food for longer than fourteen weeks, 

 * 2 mm. == one-twelfth of an inch. 



