Survey of New Zealand native legumes growing in Australia to assess their susceptibility to attack by the gall wasp Trichilogaster acaciaelongifoliae (Pteromalidae).
- Author
- Hill R
- Pages
- 11 pp
- Summary
- Sydney Golden wattle (SGW) or Acacia longifolia is native to South East Australia (Figure 1) where it is a very common plant. It is a weed of increasing importance in New Zealand where it is invading habitats such as back dunes and wetlands, threatening biodiversity values in Northland and Manawatu. SGW is a weed in other parts of the world too, notably in Portugal, where it forms monocultures in vast areas of coastal dunes (Marchante et al., 2011). It was once a serious weed in South Africa. However, in the 1980’s, two insects were imported from Australia (the native range of the wattle) as biological control agents. These have controlled the weed so well that it is no longer regarded as an environmental threat in South Africa (Impson et al., 2011). One of the biological control agents used in that program was a minute pteromalid wasp called Trichilogaster acaciaelongifoliae (Figure 2). Adult wasps lay eggs into flower buds early in development. These remain dormant for many months until the following winter when galls begin to form in place of the bud. Each gall represents one less pod producing seed in the following spring. Galls can be large and can deform and kill branches. Heavy gall loads can even kill plants. Attack by this wasp has reduced the annual seed production of SGW in South Africa by over 90%. It is proposed that this insect should be introduced to New Zealand for the biological control of SGW here