Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

Autumn Activities

Tradescantia leaf beetle pupal case.

Tradescantia leaf beetle pupal case.

There are a few things you might want to fit in before the wind-down towards winter. We would be very interested to hear about what you find.

Boneseed leafroller (Tortrix s.l. sp. “chrysanthemoides”)

  • Check release sites for feeding shelters made by caterpillars webbing together leaves at the tips of stems. Also look for “windows” in the leaves and sprinkles of black frass. Small caterpillars are olive-green in colour and become darker, with two parallel rows of white spots, as they mature.
  • Any harvesting of caterpillars should be left until spring.

Broom gall mites (Aceria genistae)

  • Check release sites for galls, which look like deformed lumps and range in size from 5 to 30 mm across. Occasion- ally galls can be found on broom that are not made by the gall mite, but these are much less dense. We are happy to help confirm the identity of any galls you find.
  • Harvesting of galls is best left until spring when predatory mites are less abundant.

Gall-forming agents

  • Early autumn is the best time to check release sites for many gall-forming agents. If you find large numbers of galls caused by the mist flower gall fly (Procecidochares alani) and hieracium gall wasp (Aulacidea subterminalis) you could harvest mature specimens and release them at new sites.
  • Do not collect galls caused by the hieracium gall midge (Macrolabis pilosellae) as this agent is best redistributed by moving whole plants in the spring.
  • At nodding and Scotch thistle gall fly (Urophora solstitialis and U. stylata) release sites look for fluffy or odd-looking flowerheads that feel lumpy and hard when squeezed. Collect infested flowerheads and put them in an onion or wire mesh bag. At new release sites hang bags on fences and over winter the galls will rot down allowing adult flies to emerge in the spring.
  • At Californian thistle gall fly (Urophora cardui) release sites look for swollen deformities on the plants. Once these galls have browned off they can be harvested and moved to new sites (where grazing animals will not be an issue) using the same technique as above.

Tradescantia leaf beetle (Neolema ogloblini)

  • Check release sites, especially the older ones. Look for notches in the edges of leaves caused by adult feeding or leaves that have been skeletonised by larvae grazing off the green tissue. You may see the dark metallic bronze adults but they tend to drop or fly away when disturbed. It may be easier to spot the larvae, which have a distinctive protective covering over their backs. The white, star-shaped pupal cocoons may be visible on damaged foliage.
  • We would not expect you to find enough beetles to be able to begin harvesting and redistribution just yet.

Tradescantia stem beetle (Lema basicostata)

  • Most release sites are still fairly new but there is no harm in looking. The black knobbly adults also tend to drop when disturbed, but look for their feeding damage, which consists of elongated windows in the upper surfaces of leaves or sometimes whole leaves consumed. The larvae inside the stems will also be difficult to spot. Look for stems showing signs of necrosis or collapse and brown frass.
  • We would not expect you to find enough beetles to be able to begin harvesting and redistribution just yet.