This is a final research report from Hort Innovation’s historical archives. Please note that as these reports may date back as far as the 1990s, the content and recommendations within them may be superseded by more recent research.

What was it all about?

The South African citrus industry was expected to become a greater competitive threat to Australia in global export markets in future due to the projected growth in production from 78m to 120m x 15 kg carton equivalents between 2005 and 2020. The main crop increase was in navel and lemon production. The volume distribution included 64 per cent export, 17 per cent domestic, 19 per cent processed and revenue, 86 per cent export, 12 per cent domestic and 2 per cent processed. Expansion into Asia and the Middle East was therefore a key priority for South African producers.

Research and Development (R&D) was grower funded and structured to gain access to all available expertise in the country (research institutions, universities, etc). The primary focus was on applied and basic research, technical extension, improved cultivar and rootstock options and market access. Australian expenditure on citrus research was similar to South Africa ($2.3m), however, with less commercial outcome. Australia’s R & D strategy was lagging behind its competitors and required urgent review. Succession planning was a recommended part of this strategy.

Cultivar development was a business in South Africa and expanding rapidly. Citrogold, one of South Africa’s leading variety commercialization companies, had commercialized 4,382 hectares of citrus in grower groups with 1264 hectares on order (refer table 1 below). The Nadorcott (Afourer) was the most widely planted late mandarin variety but cross-pollination was the greatest challenge. The Or was not recommended in dry arid conditions and was a lot more difficult to produce. The Mor had the greatest potential in Australia and was compared with DPI seedless murcott selection 2. Seedless lemons had potential and could be used as a cross-pollination buffer. The days of planting new varieties freely with no tree and or production royalties were considered to be over. Australia was therefore recommended to become a player in the global variety development arena by commercializing industry owned varieties internationally.

A range of pre-and post harvest R&D control measures, production and packhouse practices and protocols were identified for testing under Australian conditions and included:

1. Mating disruption and control methods of key pests and diseases in Australia; the use of beneficial predators for the control of aphids, mealy bug, soft scales, citrus thrips and mites.
2. Crop load and fruit management strategies to improve fruit size, reduce the risk of peteca (lemons), the incidence of creasing and splitting and colour improvement.
3. Production practices for a range of new mandarin, lemon and orange varieties currently in Australia.
4. Twelve varieties were identified for importation into Australia.
5. Fungicide resistance (FR) was a major concern globally and was rapidly on the increase. FR management in the field and in the packinghouse required a lot more attention in Australia and guidelines were identified for future implementation in a bid to reduce waste losses and save costs. The initiative by the Cold Chain Centre (Australian Logistics Assured) in Australia to introduce uniform field, packinghouse and shipping protocols deserved greater support from industry.

Greening disease had spread significantly in South Africa and was very costly to control. Australia must continue to enforce its strict phytosanitary policy to prevent Asian greening to spread to Australia.

Key outcomes:

New production practices were identified that enabled Australian citrus growers to be more competitive and cost effective in the long term.