208 A. D. PEACOCK — ENTOMOLOGICAL PESTS 



At Onitsha no caterpillars were found. Whether there be any other reason 

 or no, the fact remains that the beds received unremitting care and were kept 

 beautifully clean from weeds, as were the surroundings. 



In order to get the cocoa beds at Ibadan into as clean a condition as possible, 

 so that future work would be facilitated, an agricultural pupil was deputed 

 specially to look after them. His duties were to weed the beds and collect any 

 caterpillars, and most important, rake carefully round the base ot: the plants to 

 find any chafer beetles and grubs. These measures were repeated weekly for 

 about eight weeks but were found only temporarily efficacious. Active cater- 

 pillars and flying beetles cannot be permanently defeated in this way. 



Some spraying experiments were made to test what strength of insecticide may 

 be applied with safety to young cocoa. Baskets of young plants two months and 

 eight months old were sprayed with a mixture of Paris green and lime of twice 

 and four times the normal strength. (Normal strength : — 1 lb. Paris green, 

 2 lbs. lime, 200 gallons water.) Three applications, at intervals of a fortnight, 

 were given. The time of the experiment was the dry season, during September, 

 but the plants were kept very carefully shaded. None of them succumbed. 



Plants treated similarly with twice the normal strength of lead arsenate, were 

 similarly unaffected. (Normal strength :~~ 1 lb. lead arsenate, 120 gallons water.) 



In another spraying test at Ibadan, 12,500 cocoa plants were treated with a 

 normal mixture of Paris green and lime, and 320 plants with lead arsenate. The 

 insecticides were applied with Strawson's " Antipest " Knapsack Sprayers at a 

 total cost of 11 s. 6d. — including labour of two pupils for 42^ hours (10a-.) and 

 chemicals (Is. 6d.). The plants certainly benefited by the treatment, the effects 

 lasting for quite a fortnight. 



A similar test with cocoa and kola at Agege was inconclusive, owing to bad 

 weather and the thickness of the shade plants. 



The rules for combating leaf-eating caterpillars and beetles therefore resolve 

 themselves into the following : — 



1. Cleanly farming and the segregation of cocoa beds from maize. 



2. A combination of .hand-collecting and spraying. While weeding is being 

 done in the nursery beds, troublesome insects should be collected at the same 

 time and then destroyed ; subsequently the beds should be sprayed. 



3. Unremitting watchfulness and care should be maintained. 



The small amount of work necessitated at each short periodic examination of 

 the beds pays better than using operations on a larger scale at rare intervals. It 

 is not sound policy to allow plants to get into such a state that radical measures 

 are imperative ; " prevention is better than cure." 



Pod Borer. 



It is regrettable that little opportunity was afforded for work upon this serious 

 pest and also that the specimens found in the collection on assuming duty had 

 suffered from the climatic effects to such an extent that identification was impos- 

 sible, and even the generic name can only be hazarded (? Myelois). 



The caterpillars of this Phycid moth are a feature at Agege ; but they have 

 not been noticed from the south of the Eastern Province, where a considerable 

 amount of cocoa is grown. 



