On the Value of Poison Bait for Controlling Cane Grubs. H 



Tn addition to the foregoing advantage, tins method of Iniryiim' the 

 bait -woukl ensure the destruction of numerous eggs, and, moreover, 

 provide ideal conditions for the germination and after development of 

 the cow-peas, which, if sown near tlie surface, would be more likely to 

 suffer from dry spells that sometimes occur about the beginning of the 

 year. 



The dry method of administering insecticides is not only chea])ei" 

 but far more convenient than spraying with licjuids in the ordinary way. 

 Various mechanical contrivances and powder bellows have been spcn-ially 

 designed for this class of Avork, but in the present instance the usual 

 pole and bag method would. 1 think, meet requirements. AVith this 

 simple appliance, consisting of a wooden bar about 4 feet long with a 

 cloth bag fixed at each end to contain the insecticide, a man could treat 

 from 3 to 4 acres a day, doing two rows of peas at a time by merely 

 walking between them and slightly jarring or shaking the stick so as to 

 cause a fine cloud of dust to settle down on tbe plants. Sucii aiqilication 

 .should be made either at night, late in the evening, or in the earl\- morn- 

 ing when there is little or no wind and the leaves are wet with dew. 

 Hy observing certain rules the work is performed without risk to the 

 operator, and danger is well-nigh impossible, as the ])owiler is shakt^n a 

 few inches only above tbe ground and ov(n^ a very ]iiiiit(Ml area. 



COST PER ACRE. 



Seeing that our cane grub is far harder to kill than any s])ecies of 

 leaf-eating caterpillar, dusting operations, although limited to a narrow 

 band of verdure, would need to be done thoroughly. 



The comparative cost of material per acre for both ar.senicals works 

 out ai)proximately as follows: — 



Copper arsenate (undiluted). S 11). at Is. 6d. = 12s. per acre. 

 Copper arsenate and waste Hour (1-8 foruuila), 2 11). at Is. bil.=3s. 



per acre. 

 Arsenious acid (undiluted), 10 lb. at od.=2s. 6d. per acre. 



To this nnist be added the value of the cow-pea seeds, which at the 

 })res<nit market rate of about 38s. a bushel would be something like 10s. 

 per acre; these, however, could no doubt l)e grown by the faniici' for 

 nuich less than it would cost to purchase them. Pi'esuniing thai a man 

 could dust 4 acres a day, the outlay for such labour would amount to 

 about 2s. 6d. per acre; but this item, including expenses entailed l)y 

 sowing the peas and covering in the poisoned plants. w(mid. 1 presume, 

 be counterbalanced by advantages derived from the breaking uf) of egg- 

 chambers, destruction of weeds. improA'ement of both lantl and cane by 

 extra culture, and lastly by the nitrogen added to the soil by the peas. 



It is unnecessary at ])resent to give more than a rough estimate of 

 the total cost per acre for labour and material, which apparently would 

 not exceed 12s. 6d. for the white arsenic treatment, and pr()i)al)l\- les.s 

 than 10s. if the cane farmei- were to grow his own cow-peas. 



