INSECT ENEMIES AND FUNGOUS DISEASES 39 



A practical means of sure death for sucking insects is the use of 

 a contact poison. A contact poison is one that kills the insect by 

 coming in contact with its body. Poisons on the plant do not affect 

 sucking insects in the least. The contact poison is applied as a spray; 

 and every twig, leaf and branch must be thoroughly gone over to 

 bring the poison in contact with every insect. 



The chewing insects are more easily combatted than the sucking 

 kind. They are destroyed by direct poisoning, that is, by poisons 

 applied to the plant and swallowed by the insect. The arsenical com- 

 pounds are used for this purpose. 



FUNGOUS DISEASE 



In plants affected with a fungous disease there are often distinct 

 marks or spots upon the leaves or stems, a gradual weakening or death 

 of the part, and in many cases a complete dropping of the leaves. In 

 the course of the disease the parts affected take on a mildewed or rusty 

 appearance. In woody plants the presence of fungous disease in the 

 form of heart-rot may not be readily revealed. Bracket or shelf-like 

 fungous growths on the sides of trees indicate the presence of disease 

 and the need of special treatment. It does no good to remove the 

 growth from the bark, as it is purely the fruiting (spore-bearing) body, 

 and not the real source of the trouble that is removed. A specialist in 

 tree diseases should be consulted. 



Many fungous troubles can be controlled and dispelled by sever- 

 ing and destroying the affected parts and by promptly removing any 

 traces of plants that have been diseased. Leaves dropping from dis- 

 eased plants should be raked up and burned. Spraying with suitable 

 fungicides is practiced in preventing and combating many fungous 

 diseases. 



APPLYING REMEDIES 



Most insecticides are applied wet as sprays. There are a few 

 forms, however, that are used dry in the powder form. Spraying is 

 done by means of any machine that will force a liquid into a spray. 

 Dealers offer any number of forms, both small and large, from which 

 one can make a selection suitable to his needs and purpose. Dry 

 powders are applied with a blower or bellows if an even distribution 

 is desired. Usually a tin duster, which is nothing more than a tin 

 pail with a perforated cover, will do. Spraying is more reliable than 

 dusting, as a spray is not so easily washed off by a rain. 



