Slug war - question: Why are Slug Numbers Dropping?

[Gardini]

Hi,

I'm just learning organic gardening - I have been having a bit of a slug war for last few weeks, picking prob 20+ slugs at night and in morning. Strangely over the past 3-4 days they seem to have gone and there are very few there now. Just wondering what would be the likely cause for the drop in numbers? I have not being killing the slugs just placing them elsewhere. I have not put any sprays on the plants - just organic tea fertilizer.

An unusual request as I imagine most would be delighted they were gone but I would like to try understand why.

Any ideas or will they just come back again as quickly as they left?

Thanks in advance

[pepperhead212]

Welcome to the forum! I always use sluggo against sluggs - rated organic, they are iron phosphate pellets, which sluggs feed on, then die. When I first plant greens in the spring, I sprinkle it before planting, then plant, then cover the row with agribon, to keep rabbits away. Being covered, if I didn't put down the sluggo, they would destroy the greens! I also put it down before laying any plastic or other mulch, as they hang out under those, due to the moisture. Speaking of moisture, has the rainfall stopped in the last week or so there? That could be why you aren't seeing them as much, but that doesn't mean that they are gone - they are just deeper in the soil, waiting to pounce (STS!) as soon as a soaking rain comes!

[imafan26]

Sluggo does a good job of killing a lot of slugs and if you are diligent you can reduce their numbers a lot.
However, that being said, the slugs are probably hibernating because of the dry season and that is the real reason their numbers appear to decrease.
Less wet days and soil is drier, plants are more mature and they like young tender tips and seedlings best.

Snails and slugs are hermaphrodites so when they mate they both get pregnant and each slug can lay a cluster of up to 40 eggs. The eggs hatch in about 2 weeks and in 6 weeks they are old enough to reproduce. There numbers increase geometrically. That is why in the rainy season, they seem to appear from out of nowhere when every thing is wet and there is lush new growth. When the soil is drier and there is less food around, the eggs can delay hatching for up to 2 years.

When their numbers are low is the best time to put out bait and try to elimate as many as you can. But, don't declare victory until you haven't seen one for at least a couple of years. You will still have to bait the perimeter to make sure no new ones migrate from surrounding areas.

I don't know why you would keep them or just move them, they always will come back. They may have only one foot but they move at a pretty good clip. Predators would be cannibal snails, toads, and some birds (chickens and ducks do a good job of controlling them).

[Gardini]

Hi Thanks,

Its interesting that their numbers rebated as it has been wet in last few days after a dry period. I have a few again last night and this morning. So they will prob be back at full strength shortly.

I don't want to wipe them out due to the role they play in the soil food web, just trying to control their population or redirect them away from my patch of greens.

I was thinking of getting a slug electric fence or is there any good sacrificial plants I can consider for the future for the perimeter? or is a bait like sluggo the best method?

[rainbowgardener]

I don't think "wiping them out" is a realistic possibility. Certainly in my garden Sluggo doesn't wipe them out, just reduces the numbers some.

[Gardini]

Hi,

Might give sluggo a try and see how I fare out in the future.

Thanks all.

[imafan26]

Yeah, they are designed like cockroaches, they will inherit the earth. The best you will do is control them, eliminating them would probably be a very hard undertaking.

[john gault]

When I first started gardening I had a tremendous outbreak in slug/snail populations; they were every where, including climbing up the outside walls of my house. I think the drastic increase in numbers were from my adding tons of mulch (and some plants) to my yard -- I ripped up significant portions of grass.

However, over the next year their numbers drastically declined and today I don't see near the number of them, but I have seen a great increase in the mole population with their tunnels all over the yard. I also have a great increase of legless lizards, which kind of look like a garter snake and so many other animals. I think they took care of all the snails/slugs in my yard. I still have them, but not in the very large numbers like when I first started gardening. I don't see them as pests, they are important organisms to have in a healthy habitat.

I don't use any sprays in my garden/yard.

[applestar]

I feel like I'm seeing a lot less slugs this year, too. I was just out weeding a neglected spot, and was carelessly grabbing handfuls with bare hands and pulling... and realized I was NOT encountering slugs in my blind grabs like I have in previous years. Only wet slimy handful turned out to be spittlebug foam.

Last year I reported seeing tiny baby tree frogs EVERYWHERE. I think the little frogs eat the baby slugs. Maybe they helped decimate the population.

Oh yeah I still see them and do my best to get rid of the ones I do -- I might have been seeing more of them when we had the two brief heatwaves, so maybe they like it hotter, and it has been up and down weather, overnight lows have been much cooler for longer than usual. Another forecast for 90's coming up. We shall see....

[Gardini]

Its interesting, I had a good few of them but in the last week they seem to have dropped in numbers significantly. I have not seen any reason for this occurrence I.e increase in predators such as frogs etc. And it has been wet for the last week also - Only found one baby slug this morning? I don't know seems strange.

[imafan26]

If it was dry before, then some of the eggs may not have hatched. Since it started raining again and the soil is moist you may be seeing more in the next couple of weeks as that is usually how long they take to hatch a new generation (2-3 weeks)