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The value of pest monitoring for the economic sustainability of South African apples for the export market

Thesis (MScAgric)--Stellenbosch University, 2023.

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Main Author: Loos, Dawn
Other Authors: Hoffmann, Willem
Format: Thesis
Language:en_ZA
Published: Stellenbosch : Stellenbosch University 2023
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access_status_str Open Access
author Loos, Dawn
author2 Hoffmann, Willem
author_browse Hoffmann, Willem
Loos, Dawn
author_facet Hoffmann, Willem
Loos, Dawn
author_sort Loos, Dawn
collection Thesis
dc_rights_str_mv Stellenbosch University
description Thesis (MScAgric)--Stellenbosch University, 2023.
format Thesis
id oai:scholar.sun.ac.za:10019.1/129118
institution Stellenbosch University (South Africa)
language en_ZA
last_indexed 2026-06-10T12:41:20.497Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2023
publishDateRange 2023
publishDateSort 2023
publisher Stellenbosch : Stellenbosch University
publisherStr Stellenbosch : Stellenbosch University
record_format dspace
source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/129118 The value of pest monitoring for the economic sustainability of South African apples for the export market Loos, Dawn Hoffmann, Willem Stellenbosch University. Faculty of AgriSciences. Dept. of Agricultural Economics. Woolly apple aphid Apples -- Diseases and pests -- Control Plant diseases Agricultural pests UCTD Thesis (MScAgric)--Stellenbosch University, 2023. ENGLISH SUMMARY: There is a risk of market closure for South African Fuji apples due to phytosanitary pest interception. Pests that are proving problematic in our local climate include codling moth (Cydia pomonella), mealybug species (Planococcus citri, Pseudococcus longispinus and Pseudococcus viburni), mites (Panonychus ulmi and Bryobia) and woolly apple aphid (Eriosoma lanigerum). This is problematic due to this market paying a large premium for these fruits, not realised elsewhere and otherwise making this widely planted variety significantly less profitable to produce. While applying more pesticides to reduce pest presence is effective, it reduces environmental and economic sustainability. A 25-tree per two-hectare monitoring program was applied to address this issue, alongside codling moth trap counts, a preharvest assessment and packhouse fruit sampling. This was applied to 264 Fuji orchards across the Elgin, Grabouw, Vyeboom and Villiersdorp (EGVV) area. Data was collected biweekly and analysed using various methods appropriate to the data type. The findings of this study showed that both using this monitoring program effectively or using an aggressive spray program significantly reduced the occurrence of mealybug while woolly apple aphid was best managed using regular monitoring. Mite and codling moth presence were unaffected. Mites were shown to be managed efficiently through the use of natural predatory mites. Woolly apple aphid, while having high levels of parasitism by A. mali, was still a hindrance to export due to mummies left on fruit. The preharvest assessment showed to be significantly more effective at reducing risk when allocating orchards to a particular market, when compared to the use of a packhouse sample. Various orchard environmental factors were identified as being influential on each of the phytosanitary pests’ presence. Financial data used in partial budget modelling revealed that the use of monitoring to reduce risk of phytosanitary pests could result in a 62% increase on return on investment of annual costs per hectare. These findings show that implementing holistic monitoring systems can aid in reducing the risk of market closure while simultaneously improving growers’ financial standings and better serving the environment. Further research should be aimed at studying seasonal differences in phytosanitary pest pressures and what impacts this may have as well as place focus on industry leaders to make trade more sustainable and less volatile to closure. Masters 2023-11-28T20:28:08Z 2024-01-08T23:03:45Z 2023-11-28T20:28:08Z 2024-01-08T23:03:45Z 2023-12 Thesis https://scholar.sun.ac.za/handle/10019.1/129118 en_ZA Stellenbosch University viii, 62 pages : illustrations application/pdf Stellenbosch : Stellenbosch University
spellingShingle Woolly apple aphid
Apples -- Diseases and pests -- Control
Plant diseases
Agricultural pests
UCTD
Loos, Dawn
The value of pest monitoring for the economic sustainability of South African apples for the export market
title The value of pest monitoring for the economic sustainability of South African apples for the export market
title_full The value of pest monitoring for the economic sustainability of South African apples for the export market
title_fullStr The value of pest monitoring for the economic sustainability of South African apples for the export market
title_full_unstemmed The value of pest monitoring for the economic sustainability of South African apples for the export market
title_short The value of pest monitoring for the economic sustainability of South African apples for the export market
title_sort value of pest monitoring for the economic sustainability of south african apples for the export market
topic Woolly apple aphid
Apples -- Diseases and pests -- Control
Plant diseases
Agricultural pests
UCTD
url https://scholar.sun.ac.za/handle/10019.1/129118
work_keys_str_mv AT loosdawn thevalueofpestmonitoringfortheeconomicsustainabilityofsouthafricanapplesfortheexportmarket
AT loosdawn valueofpestmonitoringfortheeconomicsustainabilityofsouthafricanapplesfortheexportmarket