Pests and Diseases 



attacks apple trees, the Shoot and Fruit Moth of 

 black currants (123), the Wood Leopard Moth (60), 

 and the Black Currant Mite are the most difficult to 

 eradicate of all the pests in this group. Whilst they 

 are living inside the plant the only way to destroy 

 them is to cut off and burn the part attacked ; but 

 in one or two cases, currant mite especially, the 

 insects are known to emerge from their hiding-places 

 at a certain stage in their life-history, they may then 

 be destroyed by contact washes or poisonous washes, 

 or sometimes by fumigation with hydrocyanic acid 

 gas. 



FUNGUS DISEASES. 



The skin diseases of plants, such as the true 

 mildews and rusts, are not usually so difficult to deal 

 with as the diseases of which Phytophthora infestans 

 may be taken as the type. It is true that the mil- 

 dews do after a time extend down into the inner 

 tissues of the leaves, etc., but if they are combated 

 in the earlier stages of the attack such diseases may 

 be eradicated. 



Sulphur in one of its forms is generally employed 

 as a remedy for mildews and rusts. " Flowers of 

 Sulphur" was at one time considered to be a very 

 effective remedy, and it was dusted over the plants 

 by means of a small machine to which bellows were 

 attached. More recently " liver of sulphur " (potas- 

 sium sulphide) has been employed and many tons of 

 this must have been used in spraying the hop-gardens. 

 Liver of sulphur is used at the rate of \ ounce to 

 i gallon of water or in certain cases i ounce to 

 every 3 gallons of water. It should be used, 

 regularly, say once each week, until the disease is 



