Questions on: Slugs

Ron Smith, Horticulturist, NDSU Extension Service


Q: How do you control slugs in a garden? I have tried beer traps with some success and the product called sluggetta, but I don't like using chemicals in my garden. Are there other options? If I have to use chemicals, what are they and are they considered safe? (e-mail reference)

A: There are many ways to fight slug invasions. A series of shallow dishes filled with beer or decaying fruit, such as banana peels, are good. Set the dishes at ground level so the slugs are not challenged to get in them. This is probably the most effective. With the beer, the slugs drown and have a happy death. With the decaying fruit, they think they have found slug heaven and congregate in large numbers. The beer trap kills them, while the fruit just traps them. Diatomaceous earth spread in 1/2-inch bands around plants will do them in by lacerating their soft body tissue. Forget crushed eggshells because the idea doesn't work despite the many references to the contrary. One would think it should work, but it doesn't, so don't waste your time. Wood ash and hydrated lime (handle with gloves and don't inhale!) spread around garden plants will discourage slug activity. Both materials cause dehydration and burning sensations on their soft tissue. Finally, the best way to control them is to alter their environment. Slugs like cool, dark and moist locations. Prune, replant or do whatever you can to dry and heat up the location where they seem to be most pesky. Persistence is necessary to win the battle with slugs because one slug can produce young without fertilization.


Q: We have an infestation of slugs in the roots of our peonies. The slugs now are moving to our rhubarb plants. The rhubarb plants are very old and have survived without problems until this year. The slugs seem to be feeding only on the roots. We dug up one peony and got rid of the slugs. The plant seems to be growing again. What can we use to get rid of the slugs? Is there something we can use that will allow us to use the rhubarb? (Gary, Minn.)

A: I have to admit that this is the first time I've heard of slugs feeding on rhubarb roots. You can try slug pellets or place shallow trays of cheap beer around the plant. The beer will attract the slugs. They will crawl in the trays and drown. You can sprinkle diatomaceous earth around the rhubarb plant as well. This will lacerate their soft bodies and cause them to desiccate.


Q: I saw on the Internet a few weeks ago that an easy way to eliminate slugs is to spray the affected areas with a mixture of one part ammonia and two parts water. Will that mixture affect what is growing or planted later? (Fargo, N.D.)

A: You need to get the spray on the slugs to be effective. Go to this earth-friendly Web site at http://eartheasy.com/grow_nat_slug_cntrl.htm for a list of natural slug controls, including the ammonia/water remedy. The solution doesn’t harm the site or the plants. Thanks for making contact!


Q: We have an unusual problem in our strawberries. We have slugs in them. I have tried many ways to get rid of them. We had them last fall, so we put Diazinon in the soil before we planted the garden this spring, but the slugs were back after a few months. We have tried beer traps and were told to put bloodmeal around each strawberry plant to discourage them. Nothing has helped. I have laid a couple of boards out in the rows to “catch” the slugs. I gather the slugs each day and squash them. Is there something else that you could recommend? I’m getting frustrated. (Starkweather, N.D.)

A: Unless you have acres of strawberries that you are trying to make money on, the best advice I can give you, based on what you have told me, is to start over. Till the soil and allow it to lay fallow until spring. When you replant next spring, spread “Sluggo” among the berries. This organically approved, low toxicity material effectively controls slugs. The typical slug poison, metaldehyde, is quite toxic.


Q: Every morning we come downstairs to find slug trails all over our living room carpet and floor! They only appear in the living room. We took out all of the furniture to find out where they are coming in, but can’t find any holes or slugs. How can we get rid of them and how are they getting in? What germs do they carry with them? We have an 18-month-old daughter who crawls around on the floor. (e-mail reference)

A: Contact a professional pest exterminator and/or your landlord and tell them of the problem. You could put some cheap beer out in shallow dishes with runways to allow them to crawl in the dish. Slugs are attracted to brew. They drown in the beer, but do not get drunk! When you no longer collect slugs in the morning, you have completed your job. You need to find out how they are getting in. An exterminator can put down a border treatment that will prevent this from happening. Slugs do not have any more germs than humans do. They do not harbor disease and in some cultures are considered a delicacy.


Q: I noticed your question regarding slug slime on jeans. I want to know how to get those gross creatures out of my garden. I can hardly stand to pick tomatoes near the ground for fear of touching one. We tried to pour gasoline on some and light them on fire but they don't burn. (Mandan, N.D.)

A: Salt, hydrated lime, diatomaceous earth, eggshells, and "Slug-Getta." are some of the methods for controlling the slimy, voracious creatures.


Q: While sitting in her easy chair the other day, my wife discovered a slug had crawled up her leg. She knocked it off and we relocated it outdoors, but the slug left a trail of slime on her jeans. She has tried two unsuccessful washings and several spot helpers to no avail. Can you suggest something to get the slime out of clothing? (E-mail reference)

A: I must admit this ranks as one of my most unusual questions! I am by no means an expert on laundering clothing, as my wife will substantiate! She might try one of the organic citrus-based spot removers, as they seem to be pretty potent at removing stains like dog urine and red wine. It should work on the slug slime, I would guess. Certainly wouldn't hurt to try. I hope you did more than relocate the slug outdoors. If you treated this one so kindly, it might decide to reproduce itself and raise a family in the garden.


Q: I have a Lonicera x Brownii 'Dropmore Scarlet Trumpet'. It is 2-years-old and more than 5 feet tall with several blooms. Recently I noticed that something has eaten nearly all the blooms leaving the tips slightly black. Quite a few of the leaves have holes and some are stripped of all but the leading vein down the leaf. I have looked carefully at the leaves but can’t find any bugs or eggs. It leads me to think the problem isn’t aphids but I’m at a loss as to how to protect my plant. I would prefer using a natural method to control the problem since I don’t use chemicals. (Moorhead, Minn.)

A: I suspect slugs are your problem. Tonight, to see if you can catch some, set out empty tuna cans full of beer with the edge just above ground level. Any saucer will do if you don't have a supply of empty tuna cans laying around. You can't get more natural than beer!


Q: I found your answer about the pear slugs to be very helpful, but my problem is that I seem to have them inside my house. I don't know where they came from. I think that I only have one indoor houseplant. Do you think they are in it? Or is it possible that they are in the house for no apparent reason?

A: If they are truly pear slugs, I assure they are not in the house for no apparent reason. If they are, they will soon be dead! The female lays her eggs on a food source unless some pheromone or other type scent got her off course. They die with just a spray of insecticidal soap.


Q: While paging through some new garden catalogs, I read that fig trees can be grown in pots, then moved inside for the winter. Will this really work? That is, will the tree actually produce figs? What variety would be best? And what kind of care--fertilizing, "rest" during winter etc.--would it need? (My husband loves fresh figs and would be thrilled to grow his own.

Also in the catalogs, I saw an ad for a product called "Sluggo," which is advertised as an organic slug bait that is nontoxic to pets. The active ingredient is iron phosphate. I'd like to try it, but it's fairly expensive, so I wonder if you've heard any reports on it.

Finally, I should tell you that I'm the person who wrote late last summer with the hornets in the compost pile. You had some spray recommendations, but I finally broke down and called a service, and I'm glad I did. The service guy removed a nest in the pile the size of a softball. I doubt I would have had the nerve! (Bismarck, N.D., e-mail)

A: I have not heard of moving figs inside to get them to produce. I did know an Italian/American gardener when I was living in upstate New York who successfully grew figs that bore fruit by planting them against a wall that faced the sun most of the day. When winter came, he would carefully cut the branches back, and wrap the top part of the plant with water proof paper and shredded newspapers. He would then dig a trench along the side of the trees and lay them down, covering them with topsoil.

I have no experience or data with iron phosphate or the Sluggo you refer to for slug control. I cannot give you any judgement on its effectiveness.

I, too, am glad that you called a service to remove the wasp nest! I have been stung by those characters and the thought of that many being there makes my skin crawl!


Q: I have a problem with slugs in my garden and have had for years. I have perennials around the edge of my garden so tilling is impossible. I purchased some Ferti-Lome that is supposed to get rid of slugs. It is a thick liquid that is to be applied every 3 to 4 inches around the areas affected. It is supposed to be centered to attract the slugs and poison them. Can you tell me if you think this will work? (Harvey, N.D.)

A: I am familiar with the product. It works quite well, as do many others.

But first, I might try to "cure" or correct the problems as much as possible via organic methods before resorting to chemical poisons. This strategy involves removing the plant debris in the fall, raking off mulch material, picking up old boards, stones or anything these critters can crawl under. Next, turn over the garden soil where you can without damaging your perennials. The reason for tilling, or spading, is to disrupt any slugs that may have nestled in for the winter. This exposes them to the elements as well as possible predators.

Next spring, plan a diverse ecosystem garden. Mix up the species: tomatoes and cabbage, carrots and lettuce, etc. Try to space the plants a little farther apart than usual to compensate for a wet spell next summer. If you have a source of wood ashes, sprinkle it around the garden next spring after planting. On plants that are targets, spread diatomaceous earth or egg shells around the plants. My organic sources indicate that wormwood tea used as a soil drench will also control slugs. You also must know of the old trick calling for shallow containers of beer during the growing season to attract and drown slugs.


Q: Is there something that I can do this fall to prevent continuation of my slug problem in my garden and yard? They were extremely destructive in the garden this summer. If I can't find a way to control them, there's not much point in putting a garden in. (e-mail)

A: Don't give up! Keep fighting the good fight against the slimy bounders. Here is what I suggest:

Clean up the garden area well this fall. This involves removing the plant debris, raking off mulch material, picking up old boards, stones or anything these critters can crawl under.  Next, turn over the garden soil to disrupt any that may have nestled in for the winter. This exposes them to the elements, as well as possible predators.   Next spring, plan a diverse ecosystem garden. Mix up the species: tomatoes and cabbage, carrots and lettuce, etc. Try to space the plants a little more than usual since it appears we are going to be in a wet spell for some time yet. If you have a source of wood ashes, sprinkle it around the garden next spring after planting. On plants that are targets, get diatomaceous earth or egg shells and spread it around the plants.  My organic sources indicate that a wormwood tea used as a soil drench will also control them. You also must know of the old trick calling for shallow containers of beer to attract and drown them.

That's about it! I would hate to have you capitulate to these slimy crawlers by giving up the joy of gardening!


Q: I have a bush that appears as if it is being attacked by two different pests. One is a small caterpillar that forms a small compact tent, and the second pest almost looks like a tiny slug. Are they different stages of the same insect? What are they and how do I control them? (New Town, N.D.)

A: You are seeing the second generation of "pear slugs," which are not slugs at all, but the larval stage of sawflies, which are slightly larger than the standard housefly. Right now, cut off all affected branches on your cotoneaster and burn them. Next spring after leaf-out, spray with carbaryl (Sevin) or malathion. Repeat in 10 to 14 days. That should solve the problem.


Q: I am having problems with slugs eating my tomatoes and potato bugs eating the potato leaves. Is there any way to treat the soil in the fall or spring to keep this from happening next year? (Fosston, Minn.)

A: There is a product called "Slug-Getta" that is an attractive poison. You can also get slug traps from garden centers or make them yourself. To make one, push a shallow dish into the ground and fill it with beer. The slugs will be attracted to the smell, fall in and drown. Potato bugs can be controlled by using a resistant variety, or by following a strict spray program. Clean all garden litter up this fall, turn the soil over to expose the pests and have our winter help in killing them. Also, hope for a drier summer next year. 


Q: I am finding slugs around my house that are about 1.5 inches long with a sharp tail and two small antennas in the front. They are flesh colored and leave a trail of slime behind them. I used two cans of diazinon and sprinkled around on the areas of the lawn where I saw them and also sprayed tempo on the ones on the deck that I could see. Please help me get rid of them, since nothing I have tried has helped! (Washburn, N.D., e-mail)

A: On such a grand scale as yours, you have a problem that is beyond any attempts a homeowner can make to correct. They will drown in water and beer, can be controlled with sharp sand and hydrated lime and poisoned with methaldehyde, but in your case I suggest a professional exterminator to do the job, if you can get one.

The products you mentioned are insecticides and are ineffective against mollusks, which slugs are. So, do not employ those products any more because you are wasting your time and money, and causing a disruption of the ecosystem--which the slugs are also causing.

The natural predators--snakes, frogs, birds etc.--apparently are not doing their job, or are overwhelmed by the smorgasbord before them! To keep them from getting into your home, try spreading diatomateous earth in front of your doorways. That stops them cold.


Q: Well it seems the slugs don't like cold weather. I collected half a large ice cream pail of them before the weather changed. They would crawl up the outside door and around the frame at night and be on the surface of the grass so I could get them. I cleaned up all of the plants that were close so the sun could hit the soil. Will the slugs be back in the spring? (e-mail)

A: Yes, unfortunately they most likely will, but hopefully not in the same numbers! Continue your ways in thinning plant material, improve drainage, increase sunlight penetration and turn over garden soil in the fall to expose them to possible predators. Do likewise to old boards and stones. Use diatomaceous earth around suspected hideouts and place slug traps around areas where slug damage is noted.


Q I read in your column about someone wanting to get rid of slugs. To prevent slugs, I use a powder called Sevin Gardening Dust. Just dust the plant and the ground around it, and it will keep slugs and snails away. (Montgomery, Ala.)

A. I learned something new. Sevin is an effective insecticide, and it must be a good enough irritant to deter slugs as well.


Q. We have tried every kind of slug and snail killer, but we cannot seem to get rid of them. Could they have been brought in with old manure? If we don't plant anything for a year or two, would the slugs go away? (Eureka, S.D.)

A. Yes, they could very easily have been brought in with old manure, but everybody has slugs this year--even yours truly. When we find huddles or clusters of slugs, I sprinkle salt on them and that takes care of the cluster. Controlling your watering somewhat will also work to reduce the population. Keep trying. Things will improve!


Q. Have you heard of using copper barrier tape or pipe for slugs? (Fargo, N.D.)

A. Sorry, but I do not know anything about using the copper tape or pipe method you are talking about to control slugs. My attempts have all been old-fashioned: lime, egg shells and sunken beer dishes.


Q. This fall before we took the watermelon off the vine, we found big holes in them with slugs inside. They were also on the tomatoes. Can you tell us how to get rid of them so we don't have them next year? (Napoleon, N.D.)

A. There are many variations of slugs and a number of ways to control them: lime, salt, removal of mulch, adding frogs, crushed egg shells, etc.


Q. In late fall of last year I had a 20-foot mountain ash tree moved to a full sun location. The tree mover used a large unit to move the tree. A cone-shaped hole 6 feet in diameter and about 6 feet in depth. Many of the dry brown leaves still cling to the tree. My questions are: (1) Do I need to prune back the branches and (2) Do I need to apply a fertilizer?

Another question is in regard to two North Dakota hybrid ash trees. Both trees are approximately 18 feet tall and 5 years old. One of the trees developed a vertical split in the bark including the cambium layer. The growing outer part remained viable. The vertical split is near the base of the tree and approximately 10 inches long.

I put bark protectors at the base of each of the trees. These are loose-fitting plastic cylinders split lengthwise with holes for circulation to allow for expansion growth. I can not find any insect damage. Both trees had adequate leaf and growth last season. Any suggestions?

Is there any way to control slugs with a spray this spring or a repellent around plants late this summer?

I read your column every week. You provide many gardeners with helpful suggestions. Thank you. (Faulkton, S.D.)

A. No fertilization or pruning should be needed unless there are broken or diseased branches. The old leaves will fall when the new emerge.

Do nothing on your ash trees at this time. The wound should gradually close. Next fall, wrap the trees before snowfall, remove by April 1.

I know of no sprays for slug control, but there are several baits available, along with the "old beer" trap that works about as well. I have enclosed extension circular H-887, "Controlling Slugs in Home Gardens." Others may obtain a copy from any county office of the NDSU Extension Service, or by calling the Ag Communication Distribution Center at (701) 231-7882.

Thanks for writing and the flattering comment about the column.


Q. What can be done about slugs in the garden? They eat tomatoes, cabbage and carrots. Should I forget about having a garden this year? (Napoleon, N.D.)

A. There are a number of techniques for controlling slugs:

1. Diatomaceous earth (DE)
2. Beer in shallow dish buried level in soil.
3. Crushed egg shells.
4. Hydrated lime.
5. Commercial preparations--see enclosed publication H-887,
"Controlling Slugs in Home Gardens," which other readers may obtain from any county office of the NDSU Extension Service.


Q: I am writing for advice on slugs in my flowers. How do I get rid of them? (Sykeston, N.D)

A: There is "Slug-Getta," a bait that is effective; limestone powder spread over them will also do them in via dehydration and not harm the soil. Also, diatomaceous earth spread over their feeding area lacerates their soft bodies.


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