Although they may be small, slugs can cause large-scale damage to your plants within days, wiping out seedlings, crops, and produce before you even know they’re there. However, if you know what kind of damage slugs do to plants and how to recognize the signs of a slug infestation, you may be able to control the pest population and save your plants.
Slugs damage plants by consuming a plant’s leaves, flowers, fruits, or vegetables, leaving jagged holes where they chew. Slugs prefer softer foliage and foods, making young produce, seedlings, blossoms, and new growth on your plants particularly prone to slug damage.
In this article, I’ll help you identify plant damage caused by slugs. I’ll expand on what slug damage looks like and what parts of your plants are most prone to it, and I’ll help you figure out whether the pests in your garden are actually slugs. Let’s get started!
What Slug Damage Looks Like on Plants
Although many pests attack plants the same way slugs do, these slimy creatures leave behind some distinct signs that can help you pinpoint the culprit of your plant’s missing leaves, fruits, or flowers.
Still, it’s worth noting that mature slugs prefer to eat decaying matter, so they are more likely to appear on plants that need pruning due to dying leaves or stems. Additionally, some slugs might leave your plants alone if there’s a source of decaying matter, such as a compost heap, nearby.
So, let’s discuss the type of damage that slugs can do to your plants and go over the unique signs of a slug infestation.
Jagged Holes in Tender Leaves
Slugs leave behind holes in your plant’s leaves, where they have taken bite-sized chunks out of the softest, sweetest, and freshest growth.
Slugs are rasping creatures with thousands of tiny teeth, called a radula, that they use like sandpaper to scrape away plant matter before digesting it. Because of the nature of their mouths, the holes they leave in your plant’s leaves look rough, jagged, and uneven.
If the slug infestation is severe, you will notice fenestrations — window-pane-like holes — in the leaves of your plants within a few nights of the slugs’ arrival.
However, the bite marks will eventually become smoother if you control the slugs. That’s because plants can heal from slug damage. As foliage heals over the wound left by slugs, the new scar tissue on a leaf will make it appear smooth again. However, it will likely show discoloration, usually appearing yellowish or slightly brown.
Slugs also avoid mature plant leaves. Older, more established leaves have a more rigid consistency and usually taste bitter. Because slugs have difficulty chewing through tough leaves and like sweeter foods, they will generally only attack the youngest growth on a plant.
So, keep an eye out for the new growth on your plants and look for ragged, jagged bite marks and smooth, healed-over scar tissue on the foliage.
Missing Seedlings and Blossoms
As mentioned, slugs appreciate smooth, soft, sweet foods, which makes young seedlings and flowers a favorite snack among them.
Slugs can quickly wipe out fresh seedlings, killing your crop entirely. It only takes a few bites for all the leaves to disappear. If you don’t start your seeds indoors, slugs may also consume your seeds fresh from the soil.
Moreover, slugs like to consume fresh flowers, which can eliminate the possibility of a harvest for the season or devastate your ornamental flower garden.
Fruits and Veggies With Chunks Missing
Slugs are notorious for eating produce before you can pick it off the stem or vine, which can ruin your entire crop harvest for the year.
Slugs consume fruits and veggies the same way they eat leaves, leaving rough, jagged holes in them. They are particularly fond of some particular produce, including:
- Tomatoes and potatoes
- Cabbage and lettuce
- Grains such as corn and wheat
- Soybeans and other beans
However, as omnivorous opportunists, snails will even eat their least favorite food without access to something better. So, unfortunately, no plant is safe from slug damage.
Can Plants Recover From Slugs?
Plants can recover from slugs if the damage is not too severe. Seedlings have a low chance of recovering from slug damage, but larger, well-established plants have a high probability of healing and continuing to grow despite a slug infestation.
If slugs consume your plants’ flowers, fruit, or veggies, they will likely be able to recover, albeit without fragrant blooms or tasty produce. However, damage to a plant’s leaves is life-threatening.
All plants need leaves to produce energy. These leaves are like our stomachs — without them, a plant cannot photosynthesize, grow, or live. So, if a slug does too much damage to a plant’s leaves, it can cause irreparable damage.
Every plant needs at least one mature leaf to continue growing. If slugs have devastated your plants’ foliage, consuming all the leaves, your plant is as good as dead. However, if there’s even just one leaf left, you might be able to save the plant.
How To Help Plants Recover From Slug Damage
If your plants are under threat from hungry slugs, there are several approaches you can try in an effort to save them. So, let’s look at the most effective way to protect your plants from slugs:
1. Manually Remove Slugs
If you notice any slugs on your plants or see slug damage, it’s time to eradicate them. I always stress that manually removing slugs is the most effective way to eliminate them. However, since these slimy creatures are nocturnal, you’ll have to save the task for nighttime.
About an hour after dark, the slugs come out to feed on your plants. So, wait a while after nightfall. Then, set out into your garden with a flashlight, pair of gloves, and a container.
Pick off any slugs you see with your fingers, tongs, or tweezers, and collect them in your container. Pay close attention to the soil around the plant’s base and underneath the leaves, where slugs hide to avoid predators.
Collect as many as possible, then dispose of or relocate them. You can choose to save the slugs by placing them in a compost pile or a forested area, or you can drown them by pouring water into the container.
2. Pot Your Plant and Move It Somewhere Else
Once you’ve removed the slugs on your plant, pot it in a container. Potting your weak, damaged plant will allow you to keep it out of the reach of slugs and other pests. Keeping your plant in a container will allow you to nurse the plant back to health in a more controlled environment.
As you remove your plant from the soil, keep an eye out for slugs borrowing in your plant’s roots or anywhere in the dirt, and remove them.
Then, place your potted plant indoors, in a greenhouse, or on a porch. Be sure to give your plant its ideal conditions for growth, paying attention to soil humidity, temperature, and light exposure, since your plant will need all the coddling it can get to recover quickly.
4. Watch for Fresh Foliage
As soon as your plant shoots out new growth, you can be sure it will recover from the slug damage. Allow your plant to replace damaged leaves with healthy, new ones, and prune back wilted ones sparingly.
After a few months, your plant should be as good as new and ready to go back outside.
5. Prevent Further Slug Damage
Before you relocate your plants to your garden, you’ll want to prevent slugs from returning.
There are many ways to eliminate or at least deter slugs. Still, my favorites include:
- Placing coffee grounds around the plant’s base.
- Spraying the plant’s leaves with coffee.
- Setting citrus fruit traps or beer traps.
- Manually removing the slugs.
To learn more about these slug prevention and eradication methods, read my article on how to keep slugs from zucchini plants, where I’ll take you through the steps in more detail: Do Slugs Eat Zucchini Plants? What You Should Know
Slug damage can appear as:
- Rough, jagged holes or smooth scarred holes in soft, fresh foliage.
- Missing seedlings or flowers.
- Bite marks and missing chunks of produce.
Plants can recover from the damage if they still have at least one healthy leaf. To help your plant heal, remove slugs, pot the plant, and wait for it to grow new foliage. If you eliminate slugs from your garden before moving the plant back outside, you should have a healthy, slug-free harvest in no time.