Has anyone else had an infestation of this particular bean weevil? This
is going to be a bit long but please bear with me.

Yesterday lunchtime I noticed that there were half a dozen or so weevils
in our kitchen. There had been one or two on previous days but yesterday
they seemed to be getting more numerous. After lunch I decided to
investigate. To my horror I discovered that my larder of dried beans,
beans both for sowing in spring and for cooking were the source of these
weevils! I have red kidney beans, white kidney beans, French beans and
runners. The biggest infestation was in the red kidney beans - I had to
throw about half of them away - with some of the French beans also
infested. The others were untouched - so far!

I am at a loss to know where the infestation came from as I have grown
beans from my own harvest for years and have never had an infestation
before.

Looking for information on these bean weevils from my own gardening
books did not prove helpful. The only bean weevil known to them (and to
any web pages originating from the UK) is the Sitona lineatus; my
infestation definitely wasn't that.

However, I did find a description which accurately matches my
infestation on several American websites and it turns out that what I
have is Acanthoscelides obtectus. It is widely found in America and
other sub-tropical countries and it accurately describes what I have: a
small triangular beetle with wings, about an eighth of an inch in
length. The proboscis is not pointed but snub. The grub hatches out
within what is an apparently sound bean and cuts a small circular hole
in order to exit. The descriptions I have found seem to imply that they
mate immediately and push their eggs back into the bean, thus
perpetuating the infestation within the stored beans.

And so I have several questions:

Firstly where did this infestation come from? My beans were grown on my
allotment but I haven't heard of any of my neighbours having this
problem. The only thing I did differently this year was to spread some
horse manure on the allotment, but I can't think that the weevil could
have survived in that. But were they infected while growing or did it
happen in storage? The only other possibility is that we had someone
from Zimbabwe staying in our house while we were away last August. Did
he, perhaps, bring some dried beans/peas/pulses with him? Unfortunately
I can't ask him now.

Secondly, is this weevil known at all in Britain? I could find no
reference to an outbreak over here. Since it is devastating should I
report it? If so, to whom? I don't know yet whether I shall lose all my
beans but within a week or two I have lost a good half of one type.
There may still be more to come. I've now put my beans into air-tight
bottles (should have done that long ago) - something about horses and
stable doors comes to mind!

Thirdly, is there any insecticide I can use to prevent further
outbreaks?

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"David Rance" wrote Has anyone else had an infestation of this
particular bean weevil? This
is going to be a bit long but please bear with me.
snip
Firstly where did this infestation come from?
snip

David, I've never come across a Bean Weevil, but I've seen plenty of
Golden Spider Beetle (Niptus hololeucus) and Australian Spider Beetle
(Ptinus tectus) in dried foods. (I used to be in Env. Health work). They
are fairly common in the UK and are roughly the same size - might these be
the culprits?

They usually come into the larder in bought, dried food (flour, biscuits,
etc.) although I have seen them in chocolate and they can bore through
foil wrapping into adjacent stored foods), so the source of the
infestation is sometimes difficult to determine.

The first signs are stray ones crawling around the kitchen (as you've
described). You can't use an insecticide around food; you just have to
throw away the infested foods and clean the cupboards. The other thing to
do is to then isolate susceptible foods in containers with sealed lids
(polythene is OK) for a few months until you are sure that the infestation
has gone (and any eggs you can't see are not viable).

I've had 2 problems with them myself (!) over the past 20 years: 1 came
from loose dog biscuits, the other from organic stone-ground flour. I'm
not libelling either product - just illustrating the range of foods that
can be involved. I have found that out-of-date foods tend to have the
heaviest infestations: I don't know if they just take a long time to
hatch out, or there is something in stale food that attracts them.

Good stock rotation is the key, although we've all got some 5-year-old bag
of something or other on our pantry shelves, somewhere. Haven't we?


- Tom.

On Mon, 23 Feb 2004, Tom Bennett wrote:

"David Rance" wrote Has anyone else had an infestation of this
particular bean weevil?

David, I've never come across a Bean Weevil, but I've seen plenty of
Golden Spider Beetle (Niptus hololeucus) and Australian Spider Beetle
(Ptinus tectus) in dried foods. (I used to be in Env. Health work). They
are fairly common in the UK and are roughly the same size - might these be
the culprits?

Tom, many thanks for your response. However, I'm pretty sure not. The
weevils I've seen follow exactly the pattern on the web pages that
describe them, even to the photograph! There is no sign of any
infestation on anything else in the kitchen.

We did have a weevil infestation some twenty years in some split peas
but these were slightly different, having the pointed proboscis, and
they did infest some of our other foodstuffs. The present ones are not
like them and are confined to the beans.

I've caught a few of them in a small jar in case I need to send them to
anyone. I could send you a few if you like! ;-)

The first signs are stray ones crawling around the kitchen (as you've
described). You can't use an insecticide around food; you just have to
throw away the infested foods and clean the cupboards.

Yes, of course. I was meaning for those that I intend sowing, much as
the stuff that is put on seeds that one buys.

I've had 2 problems with them myself (!) over the past 20 years: 1 came
from loose dog biscuits, the other from organic stone-ground flour.

We have cat biscuit but there is no sign of any infestation there (nor
on the cats!).

Anyway, thanks again for your suggestions. I shall keep an open mind and
continue to monitor the situation.

Best wishes, David

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+-------------------------------------------------------+
| Internet: | writing from |
| Fidonet: David Rance 2:252/110 | Caversham, |
| BBS: telnet://mesnil.demon.co.uk | Reading, UK |
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