Posted by Rambling Marge on November 21, 2009, 7:25 pm
Hello, everyone. I think I might have made a big mistake and I could use
some
help...
About a year-and-spare-change ago I started a compost heap in a plastic
grid
composer, using mainly leaves and mowed grass. This week I finally
dug into it,
and found the compost inhabited by fat creamy-white grubs
up to 2cm in length. I
didn't think much of it and simply picked them
out of the compost I planned to
use, returning some to the composter
and disposing of the others. Doing some
research this weekend, I
discovered to my dismay that what I'm dealing with are
vine weevil
larvae!
Here's what worries me: I used the soil they produced throughout most
of my
garden, and although I'm sure I removed all the grubs before
using the soil, I'm
still worried whether there are any sneaky grubs
eating through my plants. I'm
also not quite sure whether to expect all
the eggs are hatched; I didn't *see*
anything that might have been eggs,
but that's hardly any assurance, right?
On the other hand, most of the information I've read focuses on the
disaster the
larvae make in potted plants - and I've got an outdoor
garden, complete with a
surrounding forest of Other Stuff the larvae
can nibble on, and hopefully an
array of natural enemies they can fall
prey to. Furthermore, I've been working
in this garden for nearly ten
years now, and although I've often seen adult vine
weevils lurking
about in the summer, I've never had any problems with them,
whether
it's the adults eating the leaves, or the larvae at the roots (and this
week is the first time I've ever actually *seen* the larvae).
I've read through this tread - http://tinyurl.com/ybg8ojt - but I'm
still not
really sure what to do. Should I start applying insecticide
just to be safe, or
wait to see if there's any damage being done? I
repeat, I've never had problems
with these larvae before, but then
again, I've never used soil they'd frolicked
about in before.
And what should I do with the composter? Should I leave the larvae in
there and
pick them out before usage? (I got the impression they were
churning out some
nice compost) Or dispose of them all and good
riddance? Is there any way of
preventing them showing up again, apart
from insecticide?
Sorry about the long post - and thank you for any advice you might
have!
Cheers,
Marge
--
Rambling Marge
Posted by Rambling Marge on November 22, 2009, 5:47 am
Ok, new idea. These grubs seem too big to be vine weevils; after more
research
I'm pretty sure these are cockchafer larvae. Pests and
root-eaters, the lot of
them. What should I do?
--
Rambling Marge
Posted by lannerman on November 22, 2009, 9:15 am
,Rambling Marge;870300 Wrote:
> Ok, new idea. These grubs seem too big to be
vine weevils; after more
> research I'm pretty sure these are cockchafer larvae.
Pests and
> root-eaters, the lot of them. What should I do?
Hi Marge, IMHO 2cm. long is too big for vine weevil larvae and when I
first read
your post cockchafer grubs were the 'beasties' that sprang
to my mind.
Whilst they will do alot of dammage, they have to be there in really
big
numbers! some while ago they were really doing dammage at my local
golf club,
and when they were digging an area to see what the problem
was the number of
grubs was unbelievable. So, IMO if you have
physically removed all the larvae
that you can see, I think you should
be OK as where as vine weevil have an
annual life cycle, cockchafer I
think take 2-3 years to mature.
Best Wishes from 'rambling' Coenwall
--
lannerman
Posted by gardengal on November 22, 2009, 9:30 am
On Nov 21, 4:25 pm, Rambling Marge
> Hello, everyone. I think I might have made a big mistake and I could use
> some help...
> About a year-and-spare-change ago I started a compost heap in a plastic
> grid composer, using mainly leaves and mowed grass. This week I finally
> dug into it, and found the compost inhabited by fat creamy-white grubs
> up to 2cm in length. I didn't think much of it and simply picked them
> out of the compost I planned to use, returning some to the composter
> and disposing of the others. Doing some research this weekend, I
> discovered to my dismay that what I'm dealing with are vine weevil
> larvae!
> Here's what worries me: I used the soil they produced throughout most
> of my garden, and although I'm sure I removed all the grubs before
> using the soil, I'm still worried whether there are any sneaky grubs
> eating through my plants. I'm also not quite sure whether to expect all
> the eggs are hatched; I didn't *see* anything that might have been eggs,
> but that's hardly any assurance, right?
> On the other hand, most of the information I've read focuses on the
> disaster the larvae make in potted plants - and I've got an outdoor
> garden, complete with a surrounding forest of Other Stuff the larvae
> can nibble on, and hopefully an array of natural enemies they can fall
> prey to. Furthermore, I've been working in this garden for nearly ten
> years now, and although I've often seen adult vine weevils lurking
> about in the summer, I've never had any problems with them, whether
> it's the adults eating the leaves, or the larvae at the roots (and this
> week is the first time I've ever actually *seen* the larvae).
> I've read through this tread -http://tinyurl.com/ybg8ojt- but I'm
> still not really sure what to do. Should I start applying insecticide
> just to be safe, or wait to see if there's any damage being done? I
> repeat, I've never had problems with these larvae before, but then
> again, I've never used soil they'd frolicked about in before.
> And what should I do with the composter? Should I leave the larvae in
> there and pick them out before usage? (I got the impression they were
> churning out some nice compost) Or dispose of them all and good
> riddance? Is there any way of preventing them showing up again, apart
> from insecticide?
> Sorry about the long post - and thank you for any advice you might
> have!
> Cheers,
> Marge
> --
> Rambling Marge
I'm not sure I'd panic yet :-) First, there is no guarantee that what
you are dealing with IS vine weevil larvae -- a great many soil and
compost dwelling insects produce fat grub-like larvae, much of them
beneficial. Vine weevil larvae is also larger than what you describe,
typically 10-12 cm and with a distinctive "C" shaped curve. Personally
without a confirmed ID, I'd remove them from any compost I was
applying now and destroy and wait to see what happens in spring when
they should become active. If you DO have a problem then - and I doubt
you will - then you can apply beneficial nematodes. Nematodes need
warm soil conditions to be effective so applying now would be a waste
of product/money and may not even be necessary.
btw, an active compost operation that attains sufficient heat should
discourage vine weevil larvae - both the turning/aeration and the heat
generated will kill off any eggs that were laid that were not consumed
by other soil organisms.
XML site map