PaDIS sets PHBG straight on dock moth

Have you ever noticed a colourful clear winged moth hanging around your healthy dock plants?

No because you eradicated dock from your property because its an agricultural nuisance…

That’s great news, but if you have dock you may be seeing the introduced insect the dock moth (Chamaesphecia doryliformis), which is actually an introduced biological control for the weed dock.

During the 1980’s the dock moth was released onto 170,000 plants, spread across 150 sites in the South West of Western Australia.

The release was part of a national program run in partnership between the (then) Department of Agriculture Western Australia and the Meat Research Corporation.

This partnership led to the establishment of the dock moth across South Australia, New South Wales, and  Victoria, with follow on releases in Western Australia.

What is dock?

Broadleaf Dock weed

Broadleaf dock an invasive agricultural weed .    – Image via Victorian Resources Online

There are a few different types of dock with broadleaf dock, recognisable for its broad green leaves, flowering from September to January.

Each plant can produces up to 60,000 seeds which germinate in Autumn and Spring. The fruit can be spread via water and can stick to wool, fur and clothing, it is often also spread through contaminated hay and grain products.

Although established, the weed is sensitive to competition as seedlings. Control options can include cultivation for seedlings, broadleaf selective herbicides in grass based pastures, or blanket wiping with glyphosate in meadow pastures containing legumes.

Characteristics of the dock moth

Characteristics of the dock moth –

  • Wasp like in appearance with narrow clear wings and bright colours.
  • Females are 15mm long with distinctive black, white and orange bands, yellow legs with orange and black antennae.
  • Males are smaller at 12mm with yellow-brown bodies, yellow legs and dark antennae.
  • Males have a tuft of scales at the base of the abdomen that resembles a fan.
  • Larvae feed on the roots of the dock plants and can grow up to 25mm long.
  • Larvae are never seen above the ground, and have a shiny body and a brown head.
  • The dock moth has a life cycle of one year, with most of the time spent as larvae in the root of a dock plant.
  • The long life cycle of the dock moth means it spreads relatively slowly.
  • Docks were popular wild edibles during the Depression due to their tart, lemony flavour.

 

dock moth

 

 

A male dock moth note the fan shaped tuft of scales at the end of the abdomen

 

 

 

 

Dock moth larvae

 

 

A dock moth larvae, they are never seen above ground.

 

 

 

Images sourced via the dock moth information page on the Department of Primary Industries and Regional Development (DPIRD) website.

Catch 22

It’s a catch 22 if you see this moth, it only thrive in areas with mature healthy dock plants.

When the moth becomes established the dock plants die off during late Spring and Summer. This is due to the moth larvae eating out the plants roots while it is dormant.

During the Peel Harvey Biosecurity Group (PHBG) consultation events for the proposed Pest Rate landholders kept mentioning the nuisance weed dock.

Even though dock may be around the Pest and Disease Information Service (PaDIS) haven’t received a report of a dock moth over the last 12 months.

So we want to know if you have.

 

If you see an insect, or plant, and your not sure of the identification you can report it using the MyPestGuide reporting tool. An Officer from PaDIS will get back to you in 48 hours  with identification, and if needed, control information.

Teele Hooper-Worrell from the PHBG says “I am now taking pictures of all the bugs I see! There are currently alerts out for the European wasp and the brown marmorated stink bug, so whenever I see an insect I don’t know, I send a report in. It’s true PaDIS get back to you in 48 hours as well”

 

The brown marmorated stink bug.

The brown marmorated stink bug.
Photo credit: Kristie Graham, USDA ARS, Bugwood.org (©2018 Kristie Graham, USDA ARS, Bugwood.org)

 

Want to see what people are reporting on? You can check out community reports on the MyPestGuide community website.

 

 

 

 

 

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