DESTROYING INSECTS 



345 



therefore, generally free from these spores. The selection 

 of resistant varieties is another important means of pre- 

 venting disease. The purchase of seeds from infected 

 sections is a common means of spreading diseases, for the 

 spores of many diseases are carried on seeds from place 

 to place. The treatment of seed to kill the spores is there- 

 fore an effective method of dis- 

 ease prevention. Many diseases 

 are also carried in the manure. 

 Throwing old diseased plants in 

 the compost or manure pile and 

 afterwards spreading this on the 

 land is a very common method 

 of infecting crops from season 

 to season. All refuse from 

 diseased plants should be de- 

 stroyed. 



Destroying Insects. Insect 

 attacks can be prevented best 

 by spraying. " In spraying, it is 

 necessary to apply the spray as 

 soon as the insects appear, as it 

 is easier to control them at that time than after they be- 

 come numerous. Successful spraying depends largely upon 

 selecting the most effective spray and upon doing the work 

 thoroughly and at the right time. 



There are many spray pumps used for vegetable garden- 

 ing work. The bucket sprayers are the most serviceable 

 to use where the crops are either too close together or too 

 far advanced to use the barrel or power sprayers. Barrel 

 pumps are the most satisfactory for general crops, as they 

 are cheap and require less labor than the hand sprayers. 



184. Barrel sprayer. 



