South African Avocado Growers’ Association
2015 Yearbook
Volume 38
Table of Contents
5 Chairman’s Report
M Baker
POSTHARVEST
6
Influence of
photo-selective shade nettings to improve fruit quality at harvest and during
postharvest storage
PP Tinyane, D Sivakumar and Z van Rooyen
9 Four increasingly important physiological disorder variants
of South African ‘Hass’ avocado fruit
FJ Kruger and D Lemmer
19 Comparison of the black cold damage sensitivity and ripening
uniformity characteristics of the Maluma and Hass avocado cultivars
D Lemmer and FJ Kruger
ENTOMOLOGY
28 Entomopathogenic nematodes (EPNs) for the control of false
codling moth Thaumatotibia leucotreta (Lepidoptera: Tortricidae) in
avocado orchards in South Africa
WP Steyn, MS Daneel, AP Malan and MM Slabbert
34 Indigenous heteropterans and related volatile secondary
metabolic compounds occurring on a range of indigenous trees in South Africa
FA Botha, PS Schoeman and BM Botha
38 Fruit flies and avocado production – a world perspective
T Grové and MS De Beer
46 Stink bugs on avocado. Progress report
PS Schoeman and FA Botha
HORTICULTURE
51 The skin colouring problem of ‘Hass’ avocado fruit during
ripening
N Mathaba, TP Mafeo and FJ Kruger
58 Can glycine betaine be used to improve ‘Hass’ avocado
production? Progress report – Year 2
RJ Blakey
60 Calibrating soil-based irrigation norms of avocado using plant
indicators
NJR Roets, SP Schoeman and NR Murovhi
66 Effect of irrigation management on avocado ripening: Long term
consistency would seem to be more important than short term variations
FJ Kruger, D Lemmer and NJR Roets
72 Effect of spray and/or soil application of paclobutrazol, and
spray application of potassium nitrate during flowering on new shoot growth and
cropping of Mendez avocado
SA Oosthuyse and M Berrios
76 Growing avocados under shade netting. Progress report – Year 2
RJ Blakey, Z. van Rooyen, JS Köhne, KC Malapana, E Mazhawu, SZ Tesfay and MJ
Savage
80 Investigating root phosphite quantification methods for
optimising foliar spray application in avocado. Preliminary report
A McLeod, J Ma, P Novela, M Nyoni, B Nzanza, M Stander and P Pieterse
88 Phosphonate treatments as part of early preventative control
of Phytophthora root rot, pre- and post-planting. Preliminary report
M Grobler, J Meyer and J Liebenberg
92 Evaluation of alternative methods to stem injections to apply phosphonate to avocado trees for Phytophthora control, i.e. bark and soil
penetrants to enhance phosphonate uptake. Final report
M Grobler, J Meyer, JJ Serfontein and J Liebenberg
98 New methods of post-harvest disease control: Using thyme oil
fumigation
M Bill, D Sivakumar, Z van Rooyan and ZS Mavuso