CHAP. XI.] THE CONTROL OF INSECT PESTS OF CROPS. Ill 



I i Knapsack Spi 



Knapsack Sprayers arc suitable for general work in gardens, 

 fruit-gardens, and on crops in moderately small areas up to about 

 five acres, ["he) arc also used extensively in the case oi permanent 



and valuable crops. Mich as tea and coffee, which arc grown 

 on hillsides where it would be impracticable to use larger machines. 



. 



