CONTENTS. 



Page. 



Introduction 5 



Influence of cultivation, pruning, and climate 6 



Periodicity in scale insects 6 



Nature of the injury occasioned by scale insects 7 



The natural enemies of the citrus scale insects 8 



The direct means of controlling citrus scale insects 9 



The gas treatment 9 



Sprays for citrus trees 15 



Citrus scale insects : Classification and characteristics 18 



Group 1. The armored scales 19 



The long scale , 21 



The purple scale 22 



The fed scale of Florida 23 



The red scale of California 24 



The oleander scale 25 



The chaff scale 25 



The orange Chionaspis 26 



Group 2. The unarmored scales 26 



The black scale 27 



The soft scale 30 



The hemispherical scale 31 



The Florida wax scale 31 



The barnacle scale 32 



The fluted scale 32 



The mealy bug 36 



Important citrus pests other than scale insects 36 



The white fly 36 



The rust mite of the orange and the silver mite of the lemon 38 



The six-spotted mite 41 



8 



172 



