CONTENTS 



Page. 



Introduction 7 



Parasitic and predatory enemies of white flies 8 



Snails that feed on sooty niohl 9 



Climatic conditions 10 



Unexplained mortality 11 



Dropping from leaves 18 



Mortality due to overcrowdiuii; 18 



Effect of curling and dropping of leaves from drought , 19 



Bacterial diseases 19 



Fungous diseases 20 



The red fungus 20 



The yellow fungus 2G 



Tho brown fungus 28 



Fungi of little or no value as white-fly parasil es 32 



Natural efTicacy of fiuigous parasites 39 



Artificial means of spreading fungous diseases 47 



Length of vitality of spores 56 



Relation of weather conditions to fungous infections 57 



Relation between abundance of white flies and success in spreading fun- 

 gous infections 58 



Susceptibility of different stages of host insects 58 



Cost of introducing and spreading parasitic fungi 58 



■ Degree of infection obtainable 59 



Practicability of increasing the efficacy of fungous ])arasiles '60 



The disadvantages accruing to citrus trees through the use of parasitic 



fungi G9 



Summary and conclusions 70 



Index 75 



5 



