Appendix. 523 



It must be remembered that it is very inflammable and a poison, and 

 has to be applied with some care. It will also damage rootage where it 

 actually comes in contact with it, but the fumes are quite harmless to 

 plant root tissue. 



AMOUNT TO USE. 



For fruit trees infested with root aphides, such as woolly aphis, 

 currant root louse, use for apple trees, 4 oz. to each tree, for cur- 

 rants 1 oz. 



This may be made in | oz. injections all around the trees. It is 

 effective for a radius of up to 20 inches. 



Two injections are better than one ; that is, use 2 oz. to an apple 

 tree, then a week later another 2 oz. in the intermediate spaces. 



The depth of injection best to follow is not yet definitely decided ; it 

 varies between 6 and 16 inches. 



METHOD OF INJECTION. 



Special instruments are made for this purpose, the most useful being 

 the Vermorel Injector (Fig. 126); by means of this instrument a large 

 amount of ground can be got over very rapidly. 



A man and a boy can easily make 3,000 injections a day, and about 

 6,000 are required per acre if the whole land has to be treated ; but in 

 case of fruit plantations this is much reduced, owing to the immediate 

 neighbourhood of the trees only needing attention. 



USES. 



The fumes of the bisulphide of carbon are useful in destroying 

 maggots and the larvte of all insects in the soil, and also such adults as 

 ground aphides as they come in contact with. 



So far no effect has been noticed on pupse or puparia. Amongst the 

 pests which have been shown to be killed by this treatment are the larvse 

 of weevils, sawfly, chafers, click beetles ; the pear midge, and various 

 aphides, as the phylloxera, woolly aphis, and currant root louse. Ants 

 are also killed by this treatment. 



TIME OF APPLICATION. 



This is best done when the trees are regaining activity and when the 

 land is fairly but not too moist. It should not be done when trees are 

 flowering or fruiting, as it produces under certain circumstances a check 

 in growth. It is best to inject it here in March, before the buds open, 

 or in late autumn. 



The growth of plants after treatment is unusually good. 



