South African Avocado Growers’ Association
1997 Yearbook
Volume 20
Table of Contents
v Foreword
J Toerien
vii Voorsittersverslag/Chairman's Report
A A
Ernst
1 Preliminary Results on the Evaluation of Hot Water Heatshock
Treatment of South African Avocados
M Kritzinger and F J Kruger
6 Post-harvest Vapour Heat Treatment of Hass and
Fuerte Avocado
P L Weller, C Kaiser, M J Savage and B N Wolstenholme
13 Soil Boron Application for the Control of Boron
Deficiency in KwaZulu-Natal Avocado Orchards
Z J Bard and B N Wolstenholme
17 Progress with Local Selections in the Quest for More
Tolerant/Resistant Avocado Rootstock than Duke 7
Z Bijzet, S P Van Vuuren and L Schroeder
24 Cultivars and Selections in the Phase I Breeding and
Selection Programme
Z Bijzet, B Snijder and A D Sippel
28 Performance of Rootstock Cultivars in the Avocado
Phase II Evaluation Programme: 1996
A D Sippel, B Snijder, J Werksman and Z Bijzet
30 Cultivar and Selection Performance in the Avocado
Phase II Evaluation Programme: 1996
A D Sippel, B Snijder, J Werksman and Z Bijzet
35 Towards the Development of a Method for the Clonal
Propagation of Avocado Rootstocks
K Hannweg
36 Avocado Rootstock and Cultivar Evaluation at
Merensky Technological Services: A Progress Report
D J Roe, S Kremer-Köhne and J S Köhne
39 Honeybees in an Avocado Orchard: Forager
Distribution, Influence on Fruit Set, and Colony Development
M F Johannsmeier, D J Swart and T M Morudu
42 Initial Results with Regard to Flower Induction and
Fruit Thinning of Avocados
B Snijder and P J C Stassen
46 Mulching of Avocado Orchards to Increase Hass Yield
and Fruit Size and Boost Financial Rewards
C Moore-Gordon, A K Cowan and B N Wolstenholme
50 Defining the Hass Small Fruit Syndrome
A K Cowan, C S Moore-Gordon and B N Wolstenholme
52 Why are Small Hass Fruit Small?
A K Cowan
55 Avocado Tree Girdling and Fruit Thinning
S J Davie and P J C Stassen
59 Sink Demand for Starch Reserves in Avocado Trees
B P H Janse van Vuuren, P J C Stassen and S J Davie
63 What do Carbohydrate Reserves Tell us about Avocado
Orchard Management?
B N Wolstenholme and A W Whiley
68 Preliminary Studies on the Macro Element Utilization
by Hass Avocado Trees
P J C Stassen, B P H Janse van Vuuren and S J Davie
74 Can More Intensive Plantings of Avocado Orchards be
Maintained?
B Snijder and P J C Stassen
78 Artifical Exposure of Different Avocado Cultivars to
Fruit Flies
T Brink, W P Steyn and M De Beer
80 Vrugsuigende Besies op Avokado's in die
Kiepersolgebied
I J Bruwer
84 Pollination Studies in Hass Avocado in Relation to
the Small Fruit Problem
P J Robbertse, M F Johannsmeier and T M Morudu
86 Does Avocado Research Pay?
J Toerien
88 What Went Wrong with Export Avocado Physiology
during the 1996 Season
F J Kruger and V E Claassens
93 The Effect of Preshipment Factors on the Market
Quality of Fuerte Avocados - 1996 Season
G J Eksteen, J Bezuidenhout, B Suter, R Robinson, N Ray and S A Rowel
97 Alternatives to Polyethylene Wax as Post-Harvest
Treatment for Avocados
S Kremer-Köhne and J A Duvenhage
99 Update on Bacterial Canker of Avocado
L Korsten and E Towsen
101 Market Survey of Stem-end Rot and Anthracnose
on Fuerte Avocados and Comparison of Collectotrichum gloeosporioides Isolates
from Different Avocado Producing Areas
G M Sanders and L Korsten
106 Determination of Possible Infection and Alternative
Control Application Sites in Avocado Packhouses
K Van Dyk, E E De Villiers and L Korsten
109 Alternative Control of Avocado Post-Harvest Diseases
K Van Dyk, E E De Villiers and L Korsten
113 Evaluation of Trichoderma
harzianum, Bacillus megaterium, Composted Citrus Waste and Soil Solarization on Avocado with
and without Phytophthora cinnamoni ~ Preliminary Results
W P Landman, I van heerden, J M Kotzé, N Labuschagne and F C
Wehner
116 Biocontrol of Root Rot in Avocado Orchards, and Monitoring
for Resistance of Phytophthora Cinnamomi to Phosphites
J A Duvenhage and J S Köhne