József Mihály Darvas. 1982.  Etiology and Control of Some Fruit Diseases of Avocado (Persea americana Mill.) at Westfalia Estate. Phd. Thesis.  Faculty of Agriculture Department of Microbiology and Plant Pathology. University of Pretoria, South Africa.  136 Pages.

CONTENTS

Note: The pages have been adjusted to reflect changes in pagination from the original

			Page
ACKNOWLEDGEMENTS			ii
GENERAL INTRODUCTION			1
PART ONE Cercospora spot disease of avocados
1.  INTRODUCTION			2
2.  LITERATURE REVIEW			2
3.  MATERIALS AND METHODS			4
4.  RESULTS			7
	4.1  Losses caused by Cercospora spot at Westfalia Estate		7
	4.2  Observations on the symptoms and the pathogen		10
	4.3  Distribution of Cercospora spot		13
	4.4  Spore trapping of P. purpurea conidia		15
	4.5  Critical infection periods for Cercospora spot		19
	4.6  Chemical control of Cercospora spot		22
5.  DISCUSSION			26
PART TWO Post-harvest diseases of avocados
1.  INTRODUCTION			31
2.  LITERATURE REVIEW			31
	2.1  Stem-end rot		31
	2.2  Anthracnose		35
	2.3  Dothiorella fruit rot		39
3.  MATERIALS AND METHODS			40
4.  RESULTS			44
	4.1  Losses caused by post-harvest diseases at Westfalia Estate		44
	4.2  Observations on post-harvest disease symptoms and on the pathogens		46
	4.3  Distribution of post-harvest diseases and pathogens		54
	4.4  Source of inoculum of post-harvest disease pathogens		57
	4.5  Pathogenicity of post-harvest disease pathogens		58
	4.6  Critical infection periods for post harvest diseases		62
	4.7  Latent infections by C. gloeosporioides and D. aromatica		67
	4.8  Pre-harvest chemical control of post harvest diseases		71
	4.9  Post-harvest control of post-harvest diseases		74
		4.9.1  Effect of the length of the ripening time	74
		4.9.2  Effect of the removal of the fruit pedicel	76
		4.9.3  Effect of rain at harvest	76
		4.9.4  Effect of moisture condensated on the fruit	76
		4.9.5  Effect of washing the fruit in the packhouse	77
		4.9.6  Effect of sealing the cut end of the pedicel	77
		4.9.7  Effect of cellophane wrapping	78
		4.9.8  Effect of waxing	78
		4.9.9  Effect of fungicides added to the wax	79
5.  DISCUSSION			79
SUMMARY			86
OPSOMMING			88
LITERATURE CITED			90