N HANDLEIDING OOR DIE BIOLOGIESE BEHEER VAN INDRINGER HAKEA SPESIES

The document details the control of four invasive Hakea species in South Africa: H. sericea, H. gibbosa, H. drupacea, and H. salicifolia. It advocates for an integrated approach combining mechanical, chemical, and biological controls, with a heavy emphasis on biological agents to manage inaccessible mountain terrains. It provides specific biological profiles and application guidelines for six agents: the gummosis fungus (Colletotrichum acutatum), seed weevil (Erytenna consputa), seed moth (Carposina autologa), stem-boring beetle (Aphanasium australe), flowerbud weevil (Dicomada rufa), and leaf beetle (Cydmaea binotata).

• Four Hakea species were introduced from Australia to South Africa between 1835 and 1858. Three of these—syhakea (Hakea sericea), rotshakea (Hakea gibbosa), and soethakea (Hakea drupacea)—are declared category 1b weeds under NEMBA:IAS regulations and must be controlled or eradicated. Wilgehakea (Hakea salicifolia) is only a category 1b invader in the Western Cape.
• Syhakea is the most aggressive invader due to high seed production, long seed viability, wind dispersal, and a lack of natural seed predators. Seed banks for syhakea have been recorded at 1.5 million seeds per hectare.
• Mechanical control is recommended for accessible areas and high-priority conservation zones, but is unfeasible in inaccessible mountain regions. It involves cutting trees as close to the ground as possible to prevent regrowth from buds at the leaf base or side branches.
• Chemical control is limited and expensive; Tebuthiuron is the only registered herbicide and is only permitted for use against syhakea and rotshakea.
• The gummosis fungus (Colletotrichum acutatum) is a host-specific mycoherbicide that attacks syhakea, causing bark cancers and 'gummosis' (oozing gum). It is most effective when applied at the start of the winter rainy season, as spores are spread by rain splashes.
• The seed weevil (Erytenna consputa) targets immature seeds of syhakea and rotshakea. In syhakea, it can destroy more than 80% of developing seeds annually.
• The seed moth (Carposina autologa) complements the seed weevil by destroying seeds in mature, woody fruits. It has been shown to reduce accumulated seeds on some sites by up to 40% over several years.
• The stem-boring beetle (Aphanasium australe) can kill the host plant by structurally weakening the stem through extensive tunneling, which often leads to trees falling over during strong summer winds in the Western Cape.
• The flowerbud weevil (Dicomada rufa) and leaf beetle (Cydmaea binotata) provide lower levels of control. The flowerbud weevil reduces seed production by feeding on buds and flowers, while the leaf beetle's impact is considered insignificant.
• Biological control agents are highly susceptible to fire, which kills them or forces them to disperse. It is critical to re-establish agents immediately after fires, once young plants have flowered for the first time, to prevent massive seed accumulation.

APA

Wood, A., Fourie, A., Krug, R., & Gordon, T. (n.d.). N HANDLEIDING OOR DIE BIOLOGIESE BEHEER VAN INDRINGER HAKEA SPESIES. WWF South Africa. https://wwfafrica.awsassets.panda.org/downloads/hakea_afrikaans_flipping_book_hires.pdf

Chicago

Wood, Alan, Andries Fourie, Rainer Krug, and Tony Gordon. N HANDLEIDING OOR DIE BIOLOGIESE BEHEER VAN INDRINGER HAKEA SPESIES. WWF South Africa, n.d. https://wwfafrica.awsassets.panda.org/downloads/hakea_afrikaans_flipping_book_hires.pdf.

Wikipedia

{{cite report |last1=Wood |first1=Alan |last2=Fourie |first2=Andries |last3=Krug |first3=Rainer |last4=Gordon |first4=Tony |title=N HANDLEIDING OOR DIE BIOLOGIESE BEHEER VAN INDRINGER HAKEA SPESIES |publisher=WWF South Africa |url=https://wwfafrica.awsassets.panda.org/downloads/hakea_afrikaans_flipping_book_hires.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{woodndhandleiding, author = {Wood, Alan and Fourie, Andries and Krug, Rainer and Gordon, Tony}, title = {{N HANDLEIDING OOR DIE BIOLOGIESE BEHEER VAN INDRINGER HAKEA SPESIES}}, institution = {WWF South Africa}, url = {https://wwfafrica.awsassets.panda.org/downloads/hakea_afrikaans_flipping_book_hires.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }