Asparagus Fern Caterpillar

[Dottie]

This year I decided to let my asparagus have time to build up, so didn't cut any asparagus. But yesterday I saw that the ferns are covered in little green caterpillars. The ferns don't look well, so at this rate there will not be a crop next year.

I don't like to use chemicals, although having looked on like it mentions using Methomyl once per season. Not sure if it would be too late now anyway, as the ferns are infested.

Any suggestions? Too many caterpillars to just squash.

Should I just cut all the ferns down and hope for the best next year?

I already grow basil with my asparagus as this is suppose to prevent asparagus beetle.

[NOG]

I would either spray them with soapy water or just cut them dowm.

[Paulottie]

I'd not heard of the basil thing....probably 'cos it obviously doesn't work.

Don't cut em down! you must save what you can of the ferns ... they are the power house bit.

Ohh those little blighters! They are a real problem in early years as you can't afford to let them strip the young ferns. So, Unless you know a seasoned gardener or shed clearance to get some Derris dust?... (Natural pyracantha(don't quote me) based insecticide approved by soil assoc. Sadly withdrawn by by safty exec in Europe ....'lest someone should ingest it by accident'.)...Shhhhhhh some of us stocked up

No get some surgeons gloves and get squishing.... bucket of water to wash hand regularly...I like to do it to GQT!...strangely satisfying.

Its more of a long campaign than a battle. Get the adults early...always find them copulating!...just put your hand underneath as they drop off when threatened. Then another good trick is to leave a few 10" stalks in Nov when you cut down...let beetles hibernate in those and they burn them while they sleep in Jan.( hehehehehe... evil cackle)

With persistence you'll get them to a manageable population.

[Dottie]

Well my basil is only at seedling stage at the mo, but it's suppose to keep asparagus beetle at bay. So far I've not seen any beetles and I didn't get any last year, so that might be working. This year I won't pull up all the basil at the end of the season and see if it survives the winter, thereby having an earlier crop.

So I think I'll have to resort to a bucket of washing up liquid and dunk the ferns in the bucket and do a bit of hand picking and squashing too.

I didn't have a problem last year, but added 4 new purple asparagus crowns bought from Wisley earlier this year. Maybe the new crop brought the caterpillars with them? Unfortunately I planted 4 of them, 1 in each corner of the asparagus bed!

[Paulottie]

To me, the washing up liquid is a red herring...normally an aphid tactic.

Basil will not certainly not survive the Winter.

I think the beetles may have found you anyway

[DaveInBraknell]

Asparagus Beetles

Hi,

I had the same problem this year, first year crowns one night notice loads of Beetle Larvae on them, never grown it before!! Blighters..

Anyhow, squished a load, but look out also for the eggs, black dots attached to the ferns.

I did three things:

1)Squished
2)Pulled off the fern where there where loads, dropped it on the floor and stomped
3)Applied Washing up liquid.

Theory about washing up liquid spray is it blocks the breathing holes of the critters and they effectivley suffocate (I believe they breathe through their skins).

It worked...For now but as others have said it is a campaign...

Dave

[Dottie]

[QUOTE=DaveInBraknell;486387]Hi,

I had the same problem this year, first year crowns one night notice loads of Beetle Larvae on them, never grown it before!! Blighters..

Yep could well have been beetle larvae, they looked like tiny dark green caterpillars. However I didn't react quickly enough, as the next day when I went to deal with them, all the ferns yellow.

Not sure if I should already cut them down, usually it's an autumn or winter job.

Last year I just ate the young stems as they came up, so no problems. This year allowing them to grow and I thought become stronger, has not worked.

[Paulottie]

Que?....so you didn't allow ferns to grow at all last year? If not, you are lucky if they are not dead already...possibly they have burned themselves out.

The beetles will cause ferns to go papery white in patches, all yellow ferns means they are not getting any water. probably fern is broken at crown, normally by wind. Give them some support and water young plants.

[Two_Sheds]

Any suggestions? Too many caterpillars to just squash.

Put a sheet* under the plants. Shake the plants. Dispose of fallen caterpillars.

It works on cabbage whites too. Easier than picking them off individually


* could be an actual sheet. Or something similar

[Two_Sheds]

get some Derris dust?... (Natural pyracantha(don't quote me) based insecticide approved by soil assoc.

Natural doesn't mean safe.
Derris kills bees. http://www.growfruitandveg.co.uk/gra...ris_22601.html

[penny]

I squeeze all grubs and spray with liquid seaweed as well as checking daily for adult asparagus beetles and this seems to work as there are a lot less this year. We went on holiday at the beginning of june so the ferns are very tall and thick now so it is hard to see them all properly but I think vigilance pays off with these little devils, shame they are pretty beetles though.

[Paulottie]

Natural doesn't mean safe.
Derris kills bees. http://www.growfruitandveg.co.uk/gra...ris_22601.html

Unlikely, if you use it responsibly in the evenings and when the crop is not in flower. I personally don't dust asparagus beds (too big and can resist attacks) I have for many years avoided insecticides and encouraged predator and pollinator populations.

But I admit did a bit in the first year when stripping ferns could kill the crowns. I have also had cause to use it occasionally on seedlings attacked by flea beetle.

However, I do take your point and its academic now anyway....but I understand that its withdrawal was not to prevent enviromental damage by indiscriminate idiots using it; but just to prevent them ingesting it by mistake.

As I mentioned at the time if someone's stupid enough to snort it at the allotment BBQ, then they'll be doing the genepool a favour...good ol' Darwinian selection.

I do like the ol sheet on the ground trick tho.... works with pea weevil too and a piece of sticky card (easy to make) works a treat on flea beetles.