Werner van Niekerk (Macadamia Nursery Association Committee Chairperson) and Dr Elrea Strydom (SAMAC)
The Macadamia Nursery Association is the voice of all nurseries producing macadamia seedlings in South Africa. The role of the Macadamia Nursery Association is to ensure that high-quality trees are deployed in the industry, and to serve as the formal intermediary between SAMAC, the macadamia industry and the Seedling Growers Association of South Africa (SGASA).
SAMAC-registered and SGASA-accredited nurseries
Both SAMAC-registered and SAMAC-registered, SGASA-accredited nurseries can form part of the Macadamia Nursery Association and the Macadamia Nursery Association Committee. SAMAC-registered nurseries are nurseries registered with SAMAC as stipulated by the industry’s statutory measures. SAMAC-registered, SGASA-accredited nurseries are nurseries registered with SAMAC and who comply with SGASA macadamia audit regulations and who are audited by SGASA annually. SAMAC-registered, SGASA-accredited nurseries are promoted by SAMAC. The Macadamia Nursery Association invites all nurseries to become part of the Macadamia Nursery Association, as the buy-in of industry is required when issues of common interest to macadamia nurseries are discussed.
SAMAC research projects focussed on the nursery environment
Characterization of oomycete species (Pythium, Phytopythium and Phytophthora) associated with macadamia trees
Oomycete species from the genus Phytophthora are known to be harmful to macadamia. In 2007, a survey of oomycetes associated with macadamia nursery trees in South Africa indicated that species within the genus Phytopythium may also be damaging to macadamia. The first aim of the study is to conduct a survey of oomycete species associated with macadamia tree roots in nurseries, young orchards and older orchards. The identified species will be evaluated for their ability to cause root rot and stem cankers on Beaumont seedlings. Species that are identified as causing root rot and/or stem canker on macadamia will be used to determine whether rootstocks (Beaumont, H2, A16 and Nelmak2) differ in susceptibility to the pathogens. Knowledge generated in this project will allow us to determine which oomycete species must be regulated in nurseries and which rootstocks are best utilised in regions where oomycete species are known to be problematic.
Managing oomycete pathogens in macadamia nurseries
Several oomycete species (Phytophthora cinnamomi, Phytophthora parvispora, Pythium ultimum and Phytopythium vexans) were recently identified in a SAMAC project as being pathogenic toward macadamia. It is thus important that these pathogens should be absent from macadamia nursery trees to ensure the establishment of healthy orchards. The project aims to improve the laboratory methods used for detecting oomycete pathogens in nurseries and to investigate whether biocontrol agents are effective at excluding the pathogens from nursery tree roots when applied in nurseries. A better understanding of how biocontrol agents function in suppressing oomycete pathogens on macadamia will also be obtained. The project will improve the quality of macadamia nursery trees by reducing the probability of introducing oomycete pathogens with nursery trees into orchards, which can result in a decrease in the profitability of orchards.
Diseases and endophytes of nursery trees in South Africa
Nursery tree quality is one of the single most important factors to consider when striving for sustainable profits in your business. Very little is known currently of the diseases and endophytes occurring on the above ground parts of macadamia trees in macadamia nurseries. In Australia, a similar survey has identified the causal agents of dry flower disease and husk rot as endophytes in nursery trees. The aim of this project is to conduct a survey in nurseries for viral, bacterial and fungal diseases. This project will flag possible risks and assist in formulating strategies to mitigate these risks. We thank the nurseries that agreed to participate.