AND PROBLEMS OF SOUTHERN NIGERIA. 215 



ready for fitting sent out from England ; or that metal tanks, similar to those 

 used in the Colony for collecting rain-water, sent out from England in parts may 

 be found preferable and cheaper. 



Two courses are open to popularise fumigation. Either the farmer might be 

 encouraged by demonstration and teaching to fumigate his own seed or public 

 fumigatoria should be erected. It will be a reproach to the educated farmers of 

 the Agege, Sapele and Aba districts if they do not set an example to all native 

 farmers by using this certain method of preserving corn. 



It would be interesting to ascertain whether a fumigatorinm and store-house 

 run by private enterprise would be a paying speculation. 



INSECTS AFFECTING YAMS. 



Prionoryctes caniculus, Arrow. (Plate XXV, fig. 10). 



One specimen from Afikpo (E.P.) was sent by the Assistant Superintendent of 

 Agriculture, Calabar, about February 1912. More specimens with information 

 were received from Captain Richardson, District Commissioner, Kwale (C.P.), 

 in July 1912. 



Chafer grubs, of unknown species, were found destroying growing yams at 

 Nzula, E.P. 



The distribution of this insect is little known, and there was only one specimen 

 in the British Museum. 



Information from the aforementioned sources indicates that the beetles eat the 

 yam vines and then descend to the young growing yams in the ground and destroy 

 them. The fact of the beetles devouring the yams in the ground is interesting 

 and unusual. Nothing is known as to the life-history of the species. 



Further investigation will probably show this insect to be a serious pest. At 

 Kwale several hundred plants on the prison farm were totally spoilt. A native 

 interpreter at Uyo, E.P., gave information that for four years in succession a 

 pest had attacked yams on the ground. From a very imperfect description it is 

 possible that this species was meant. 



It is not safe, with our present scanty knowledge, to detail measures for com- 

 bating the insect In the case of the prison farm it may be of good service 

 before the yams are planted and while the ground is being prepared, to examine 

 the soil for chafer grubs and destroy them. Old decaying logs and stumps should 

 also be removed. 



The fact that the beetles fly and probably descend from the bush will cause 

 hand-picking to be only of temporary value. It will be worth while to try 

 spraying the growing vines with a stomach poison. 

 Crioceris livida, Dalm. (Plate XXIV, fig. 7). 



Larvae attacking growing yam vines were found at Uyo, E.P., in May 1912, 

 while larvae and adults were found at Ibadan on 22nd June 1912. They are 

 most probably the same insect. The grubs and adults eat the leaves and tender 

 parts of the vines. In several cases the stem just below the soft growing tip was 

 found almost chewed through. The insects at Ibadan disappeared by the 18th 

 June 1913. 



32306 £ 



