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I have what I believe to be Cinnabar moth larvae eating my Virginia creeper. How do I get rid of them? Everything I've seen on the web is how beneficial they are in controlling a weed, but nothing on how to the kill the pest.
It's interesting that there are often unintended consequences when we import insects to control noxious weeds. The cinnabar moth was brought in to control tansy ragwort, Senecio jacobaea. See the following link from Oregon's agricultural experiment station:
"'The cinnabar moth arrived when threats to native plants did not receive much public or scientific scrutiny,' McEvoy said. Now a three-year survey conducted across 25 sites in western Oregon determined that cinnabar moths have been munching on arrow leaf groundsel, a native wildflower found principally in the mountains and occasionally on the coast. Scientists had thought that the places where arrow leaf groundsel grew were too cold for the cinnabar moth. But incremental climate change may raise temperatures enough to allow the cinnabar moth to thrive at higher elevations. Although the state hasn't reclassified the cinnabar moth as a pest, the story serves as a cautionary footnote in the tansy ragwort success story."
I don't believe much thought has yet gone into methods for controlling the moths when they devour non-target plants. I would guess that you could attempt to look for eggs and remove them manually, or attempt to control the larvae of the cinnabar moth ( Tyria jacobaeae). We can't recommend pesticides as we are librarians and not licensed pesticide handlers, but you might investigate whether something like Bt (Bacillus thuringiensis) is registered for controlling moths in their larval stage. Ohio State University Extension has information about Bt's use on gypsy moth. This should give you an idea of how Bt works.
British Columbia's Island Crop Management shows images of the moth at various stages, including the eggs of the moth, so you will know what to look for.
A New Zealand web page has useful information on the life cycle of the cinnabar moth:
"Cinnabar moth has only one generation per year. Adults emerge from October onwards, but are most common in December. Eggs are laid from November to February and take about 2 weeks to hatch. Each-female can lay up to 300 eggs. Larvae are common in the field from December to March. They pass through five instars, and are most conspicuous in the latter stages when they congregate on the upper parts of the plant. When fully fed they pupate, and overwinter as pupae. Although pupae can survive considerable desiccation they are particularly vulnerable to damp conditions, and mortality can be very high in waterlogged soils."
You might also try to encourage birds in your garden, as they will eat some of the moths at caterpillar stage.
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Garden Tool: Variegated cutworms are in full force in the garden this time of year(Feb-May). Some of their favorite foods include primrose, foxglove, variegated water figwort, bearded iris, and chives. The little vandals only feed at night, so if you have suspicious holes on the leaves of your plants go out at night with a flashlight. Hand picking works, but must be done frequently. Spraying with Bt (Bacillus thuringiensis - Green Light BT Worm Killer is one name brand) works too, but plants must be re-sprayed after each rain. More information: North Dakota St. University
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June 24 2013 12:55:25