Asparagus beetles


by Richard Jones

To my mind, the asparagus beetle, Crioceris asparagi, is one of our most beautiful insects.


Asparagus beetles matingTo my mind, the asparagus beetle, Crioceris asparagi, is one of our most beautiful insects. The Mondrianesque juxtaposition of its red border, creamy yellow squares and inky blue-black outlining is just astonishing.

Although only 5-6mm long, it's a supremely elegant beetle, neatly parallel-sided, shiny, cylindrical and compact. So what a delight that almost every asparagus plant now benefits from its decoration, at least, in south-east London they do.

I'm mildly surprised that I don’t hear more about this insect. It does, after all, only eat one plant — and one that is grown and consumed with quite some considerable zeal and passion by its aficionados. Even its pale grey maggots, which are the ones that actually do all the eating, are hardly complained of.

I’m guessing that many people just don't notice they're there. Since adults and larvae only appear on the feathery leaves, they are long gone and have not yet reappeared by the time the spears are harvested in spring. And even though some plants harbour hundreds, they can’t really be doing too much damage. Or can they? I’m sure I'll be told.



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Gardeners' World Web User 12/07/2009 at 09:08

Hi On my asparagus I have asparagus beetle larvae (I missed picking off some of the eggs). I also have blackfly and another beetle which I first thought was a ladybird larvae but now realise it isn't. It's about the same size and shape as the asparagus beetle but not shiny. It has a black head and tail and a black stripe down the back but each side is orange. I thought it was eating the beetle larvae or blackfly so have left it. Was I right?

Gardeners' World Web User 13/07/2009 at 21:22

Reply to Bunnsgarden You probably have leaf beetles. Chrysolina species. There is a lovely one on garden and water mint, Chrysolina herbacea (formerly called C. menthastri) but if it is on rosemary, sage or lavender it is C. americana, the rosemary leaf beetle. See this link: http://www.gardenersworld.com/how-to/problem-solving/garden-pests-rosemary-leaf-beetle/?CMP=%20KNC-SH8218390392&gclid=CNWkiO26t5MCFQ88QwodgQR3DA

Gardeners' World Web User 13/07/2009 at 21:25

Reply to Tangy I think you were right to start. They are probably the larvae of the harlequin ladybird, Harmonia axyridis. As well as eating aphids, they will eat other soft-bodied invertebrates like asparagus beetle larvae. See the pictures here http://www.ipm.ucdavis.edu/PMG/NE/harmonia_axyridis.html

Gardeners' World Web User 14/07/2009 at 15:25

Reply to Richard Jones Many thanks. They are exactly what I have, so I hope they will feast on the remaining beetle larvae!

Gardeners' World Web User 22/11/2009 at 20:38

Update I took a small tool kit out from the cupboard under the sink today and a live asparagus beetle dropped off the lid. It must have come indoors to find somewhere to hibernate. Strange, because neither we nor any of our neigbours grow the host plant in any of our gardens as far as I know.

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