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Weed Biocontrol Autumn Activities

Gall-forming agents

  • Check broom gall mite (Aceria genistae) sites for signs of Very heavy galling, leading to the death of bushes, has been observed at some sites. Harvesting of galls is best undertaken from late spring to early summer, when predatory mites are less abundant.
  • Check hieracium sites, and if you find large numbers of stolons galled by the hieracium gall wasp (Aulacidea subterminalis) you could harvest mature galls and release them at new sites. Look, also, for the range of deformities caused by the hieracium gall midge (Macrolabis pilosellae), but note that this agent is best redistributed by moving whole plants in the
  • Check nodding and Scotch thistle sites for gall flies (Urophora solstitialis and stylata). 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 the bags on fences, and over winter the galls will rot down, allowing adult flies to emerge in the spring.
  • Check Californian thistle gall fly (Urophora cardui) release sites for swollen deformities on the 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.
  • Look for swellings on giant reed (Arundo donax) stems caused by the giant reed gall wasps (Tetramesa romana). These look like small corn cobs on large, vigorous stems, or like broadened, deformed shoot tips when side shoots are attacked. Please let us know if you find any, since establishment is not yet

Honshu white admiral (Limenitis glorifica)

  • Look for the adult butterflies at release sites, pale yellow eggs laid singly on the upper and lower surfaces of the leaves, and for the caterpillars. When small, the caterpillars are brown and found at the tips of leaves, where they construct pier- like extensions to the mid-rib. As they grow, the caterpillars turn green, with spiky, brown, horn-like
  • Unless you find lots of caterpillars, don’t consider harvesting and redistribution. You will need to aim to shift at least 1,000 caterpillars to start new sites. The butterflies are strong fliers and are likely to disperse quite rapidly without any

Privet lace bug (Leptoypha hospita)

  • Examine the undersides of leaves for the adults and nymphs, especially leaves showing signs of
  • If large numbers are found, cut infested leaf material and put it in chilly bin or large paper rubbish bag, and tie or wedge this material into Chinese privet at new Aim to shift at least 1,000 individuals to each new site.

Tradescantia leaf, stem and tip beetles (Neolema ogloblini, Lema basicostata, N. abbreviata)

  • Look for the distinctive feeding damage and For the leaf and tip beetles, look for the external-feeding larvae, which have a distinctive faecal shield on their backs.
  • If you find them in good numbers, aim to collect and shift at least 100–200 beetles using a suction device or a small net. For stem beetles it might be easier to harvest infested material and wedge this into tradescantia at new sites (but make sure you have an exemption from MPI that allows you to do this).

Tradescantia yellow leaf spot (Kordyana brasiliensis)

  • Look for the distinctive yellow spots on the upper surface of the leaves, with corresponding white spots underneath, especially after wet, humid weather. Send a photo to us for confirmation if you are unsure, as occasionally other pathogens do damage tradescantia
  • The fungus is likely to disperse readily via spores on air If human-assisted distribution is needed in the future, again you will need permission from MPI to propagate and transport tradescantia plants. These plants can then be put out at sites where the fungus is present until they show signs of infection, and then planted out at new sites.

Tutsan moth (Lathronympha strigana)

  • Look for the small orange adults flying about flowering tutsan They have a similar look and corkscrew flight pattern to the gorse pod moth (Cydia succedana). Look, also, for fruits infested with the larvae. Please let us know if you find any, as establishment is not yet confirmed.
  • It will be too soon to consider harvesting and redistribution if you do find the

Woolly nightshade lace bug (Gargaphia decoris)

  • Check release sites by examining the undersides of leaves for the adults and nymphs, especially leaves showing signs of bleaching or black spotting around the
  • It is probably best to leave any harvesting until spring.

National Assessment Protocol

For those taking part in the National Assessment Protocol, autumn is the appropriate time to check for establishment and/or assess population damage levels for the species listed in the table below. You can find out more information about the protocol and instructions for each agent in The Biological Control of Weeds Book.


Target When Agents
Broom Dec - April Broom gall mite (Aceria genistae)
Lantana March–May Leaf rust (Prospodium tuberculatum) Blister rust (Puccinia lantanae)
Privet Feb–April Lace bug (Leptoypha hospita)
Tradescantia Nov–April
Leaf beetle (Neolema ogloblini) Stem beetle (Lema basicostata) Tip beetle (Neolema abbreviata) Yellow leaf spot fungus (Kordyana brasiliensis)
Woolly nightshade Feb–April Lace bug (Gargaphia decoris)