Those snails!!!!

[stilllovingmysleep]

The little blighters (=snails) have munched up my poor hydrangea which is even in a big pot in the front garden. I keep finding them everywhere. How can I deter them? Help!!

I heard copper helps? I.e put copper wire around the plants.
We also tried a beer trap with melon bait but it mostly got slugs rather than snails.

slug pellets.

If you scatter them under the bush they will last longer as protected from light rain.

Slugs and snails are very adventurous and can trot 50 yards or more in a night. In the first week or so you will kill plenty, but you will still get them. This may make you think the pellets do not work. In fact, there are just more travelling in from round your garden. Keep scattering the pellets and you will reduce the population.

Scatter them, don't put them in heaps, to discourage anything else from trying to eat them. Once you have got the population down, you can scatter them around the borders of the bed just for the new ones that come marching in.

The only thing that ever worked for me was a beer trap or three. I tried nematodes but didn't really see much difference.

Please DON'T use metaldehyde slug pellets. They are absolutely lethal for wildlife and they poison the water supply as well. The slugs die on the surface and are then eaten by birds or hedgehogs, which will die in agony. It's evil stuff.

There are organic ones available, marketed as Slug Bait, that use a ferric compound instead of metaldehyde. The slugs affected by these tend to die underground and the pellets are supposed to be less toxic to other animals.

I've found nematodes useful - make sure that those you buy are anti-slug, as there are many kinds available. New slugs will move in to take the place of those that die, but they give you a bit of a respite just at the moment when everything is growing. By the time things have shot up, they have some resilience to slug attack.

Keeping anything really vulnerable in pots really helps - I can only really grow hostas this way.

Opinions differ

I would not want to use pellets as i am concerned about the cats of neighbours who often visit my garden. What if they eat them and get ill or even die? I would not be able to forgive myself. This morning I added many egg shells and pebbles to my hydrangea pot so let's see.

I don't know how to make a beer trap!

This is a comprehensive European report on metaldehyde with a long section on ecotoxicity, which suggest that grain-eating mammals and birds are at risk:

www.efsa.europa.eu/sites/default/files/scientific_output/files/main_documents/1856.pdf

Though some sources insist that hedgehogs can't consume enough slugs to get a fatal dose, there are peer-reviewed studies into hedgehog mortality that have concluded that metaldehyde toxicity was to blame for deaths!

www.ncbi.nlm.nih.gov/pubmed/2035215?dopt=Abstract

toxnet.nlm.nih.gov/cgi-bin/sis/search/adbs+hsdb:@term+@DOCNO+1735

But we should also be concerned for our own health. Metaldehyde gets into water and once it's there, it can't be taken out. So we end up drinking it! While it would take a LOT to be toxic to a human, there could be all kinds of non-lethal side effects.

And to add a completely non-scientific, anecdotal piece of testimony: I should add that years ago, I used to be a metaldehyde pellet user. Then one morning I found a hedgehog convulsing on my lawn. It died in agony, frothing at the mouth with a blue-tinged foam. I have always believed that I was to blame for killing it and I will never, ever use the pellets again. It is a shame that it took the death of a lovely little creature to make me change my ways.

Thanks for the link, holly. I am fond of hedgehogs and other wildlife and have been searching your document to see what evidence it cites for danger. Can you see it? I can't.

I see the part that says

"The agreed Acceptable Daily Intake (ADI) is 0.02 mg/kg bw/day based on the 2-year rat study, the Acceptable Operator Exposure Level (AOEL) is 0.1 mg/kg bw/day based on the 52-week dog study,and the Acute Reference Dose (ARfD) is 0.3 mg/kg bw based on the acute neurological findings observed from the first week of the 52-week dog study. All reference values were derived with the use of a safety factor of 100"

however I haven't yet found how many pellets you would need to eat every day for two years to reach the Acceptable Daily Intake. The agricultural bait tested contained 50g metaldehyde per kg, but I understand amateur products usually contain about 3%, but I don't know the weight of a mini-pellet.

I did find this other document which says " a 1kg hedgehog would have to directly ingest 490 pellets " and " A study by Gemmeke (1999) showed that metaldehyde pellets were least preferred by hedgehogs when given a choice between methiocarb, thiodicarb and metaldehyde, and over 2800 slugs would need to be consumed to achieve LD50 toxicity levels (based on rat LD50). Gemmeke (1995) also reported that hedgehogs would eat (dead) contaminated slugs – up to 200 in one night – with no apparent side effects."

I have not yet decided the significance of these figures. I typically scatter several dozen mini-pellets a week.

To make a beer trap, pour some beer in a bowl with a piece of fruit in it.

Thanks foresttrees; and put the beer trap where?

Just put the beer trap in the ground near the relevant plants. I chuck a few organic slug pellets in too (tend to avoid metaldehyde but interested that PigletJohn's research suggests it may be OK for wildlife if scattered thinly).

The fact that those two last peer-reviewed sources suggest that some hedgehogs are dying of metaldehyde poisoning suggests to me that it possible for certain of these animals to eat enough of the chemical to reach a lethal dose! (Info on the test here: www.sciencedirect.com/science/article/pii/S0021967301876196 )

Why might this be the case? Maybe the the toxicity levels have been wrongly calculated and are lower than suggested, or maybe some kind of accumulation is happening (though this seems unlikely given the short half-life), or maybe another factor is in play, e.g. exposure to a second chemical of some kind that intensifies the effects?

My question is: since there is credible evidence to suggest that metaldehyde HAS killed some hedgehogs, even if we don't understand the mechanisms of this exactly yet - and we do have alternative methods - then isn't it safer to set beer traps or use nematodes?

All documents suggest that lower doses may be lethal to other mammals (e.g. wood mice) and birds, so it's not just hedgehogs either.

Beer traps have been most effective for me. You can buy them, I think, but I make my own. I just sink a dish into the ground and fill with alcohol (old speckled hen been the most effective so far!). I cover with a roof tile to stop my dogs drinking it (trust me, drunk labs are NOT fun to be around).

It's sickening, isn't it? Last year they stripped FOUR lots of runner bean plants.

I have a lot of snails. After living here for 20 years, I've given up. I've learnt which plants they leave alone and I only plant them. It doesn't make for a fabulous garden, but I've never found anything which irradcates them

holly

Your document says "several cases of poisoning have
been reported where animals have had access to large quantities of the formulation"

Surely this means where they have eaten it from a storage bin? Not where they have found a few dozen pellets scattered on a flowerbed?

I'm another who avoids metaldeyde pellets, hut uses the ferric phosphate ones sparingly.

OP, in addition to all the barrier methods mentioned, do you have a young child you could train up to catch slugs and snails? I have a 7yo, he has been catching 'chompers' for me for 2 years now. I pay him based on how many he catches He is small and flexible and bloodthirsty and can get into nooks and crannies.

I sometimes do beer traps too - cheapest beer is fine. But leave a small lip of the trap (yogurt pot, whatever), sticking up from the soil so that stuff you do want, like beetles, don't fall in.

Spotted what beer do you use? I tried a couple of different "value" brands and the slugs wouldn't touch it!! If my Dad knew I was giving them the good stuff I think he'd have a heart attack...

Your slugs are posher than mine, as I do use value brands! I used the ale one, not the lager.
But I'm sure that I read that you can just use a bit of yeast and sugar in water and that does the same job?

My slugs love Guinness, but it's expensive so they only get it if I've been cooking with some. Another sort of stout someone gave me once worked well, too.

Unfortunately they turn their little antennae up at Sainsbury's Economy Bitter :(

Irene do you think our slugs might be a bit...you know...snobbish?

I fear as much, Cupcakes :( I tried yeast and sugar a couple of times as mentioned by Zebra and the slugs were like

I live in an "up-and-coming" bit of London and am worried that the sudden preponderance of naice delis and pubs serving craft ale is giving them ideas.

They'll be demanding malt whisky soon.

See, Irene, your slugs probably don't do yeast and wanted an artisan sourdough starter.