Learning how to identify pests on your plants is important for all gardeners but especially for new gardeners wanting to grow food organically.
It’s never fun to be walking through your garden and to notice that something just isn’t right. You might notice large holes in your leaves or tiny holes. Or worse, maybe entire leaves are missing from your plants!
As organic gardeners, you don’t want to blindly start applying insecticides at the first sign of a garden pest. You’ll want to first identify the problem and second make sure you use the right technique to control the problem.
Can’t you just use organic pesticides? Yes, but keep in mind that not all organic pest controls are safe for the beneficial insects that will be in your garden, and not all organic insecticides work for all pests. My goal is to help you learn how to identify the culprit pests and then give you guidance on how to deal with the problem.
Before we begin, if you’d like to watch a podcast episode instead about how to identify what’s eating your plants, you can watch it here:
As a passionate gardener, nothing is more frustrating than walking outside to find entire stems nibbled off your beloved plants overnight. While the damage can seem mysterious at first there are several likely culprits that regularly attack the stems and foliage of garden plants. By learning to recognize the signs of different pests and utilizing preventative measures, you can take action to protect your hard work in the garden.
Common Stem Nibblers in the Garden
Slugs and Snails
These slimy mollusks come out at night to feast on the tender leaves and stems of seedlings and herbaceous plants. Their rasping mouthparts can shred foliage and leave behind telltale slime trails on leaves and soil. They thrive in cool, damp conditions.
Frequency of occurrence: 33%
Cutworms
These plump caterpillars hide near the base of plants during the day, then come out at night to chew through stems at ground level. This causes healthy seedlings to topple over. Their damage can be confused with vole damage.
Frequency of occurrence: 25%
Voles
Also known as meadow mice voles are small rodents that burrow underground. They emerge to feed on stems seedlings, roots, and tubers. Vole damage can resemble cutworm damage since they chew through stems, toppling plants. They are most active at night.
Frequency of occurrence: 25%
Earwigs
While not the most common stem nibblers, earwigs can attack young transplants and seedlings, stripping the leaves and chewing the tender stems. They leave behind small, jagged holes and excrement pellets.
Frequency of occurrence: 8%
Deer and Rabbits
Hungry deer and rabbits are also attracted to the tender growth of garden plants. They rip and tear vegetation, leaving stems stripped of leaves and shoots gnawed to the ground. Damage is usually most severe at dawn and dusk.
Frequency of occurrence: 8%
Recognizing Damage from Stem Nibblers
Carefully examining affected plants and the surrounding area can provide clues to what pests are feeding on your plants’ stems and leaves.
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Slugs and snails leave behind shiny slime trails on leaves, stems, and the ground.
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Cutworm caterpillars clip stems cleanly at soil level, toppling seedlings over. Frass may be found near severed stems.
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Voles make small burrows and shallow surface runways through vegetation. Stems are clipped at an angle, often with just the top leaves eaten.
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Earwigs leave behind small, jagged holes in leaves and chew irregular notches in stems. Their excrement looks like tiny pellets.
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Deer and rabbits tear vegetation, leaving stems stripped of leaves and tips of shoots chewed off. Damage is usually higher up on larger plants.
Preventing Stem Damage
While pests can never be eliminated completely, there are several effective tactics to help safeguard your plants from these nighttime nibblers and stem shredders.
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Remove Hiding Places: Eliminate debris, weeds, and thick groundcover near vulnerable plants to eliminate shelter for slugs and snails. This will encourage them to move elsewhere.
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Use Physical Barriers: Collars made of cardboard, aluminum foil, or copper mesh around seedlings provide a physical defense against slugs. Remedy cutworm damage by placing cutworm collars made of paper, cardboard, or metal around transplants. Chicken wire fencing can help deter rabbits and deer.
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Apply Mulch: A 2-4 inch layer of coarse, shredded bark mulch makes it harder for slugs to travel to your plants. Avoid moist organic mulches like grass clippings.
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Encourage Natural Predators: Attract slug predators like garter snakes, ducks, and beetles by providing habitat. Avoid pesticides so these beneficials thrive.
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Use Slug Baits and Traps: Apply slug bait or set out beer traps to capture and reduce slug populations. Look for iron phosphate baits which are low toxicity to pets and wildlife.
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Adjust Watering Habits: Water plants at the base in early morning to avoid getting foliage wet, which attracts slugs at night. Proper watering also nurtures healthy plants that better withstand pest damage.
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Grow Vole-Resistant Varieties: Choose plants with tolerance to vole damage like daffodils, lavender, pennyroyal, catmint, and narcissus. Avoid favorites like tulips.
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Clean Up: Remove garden debris like fallen leaves and overgrown groundcover to eliminate vole shelter and food sources.
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Use Physical Barriers: For valuable plants, surround with a cylinder of 1⁄4 inch wire mesh, sunk several inches into the ground to thwart voles.
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Use Repellents: Spray or sprinkle vole-repelling products made with castor oil, garlic, or capsaicin on vulnerable plants. Reapply after rain.
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Apply Pesticides: As a last resort if all else fails, spot treat vole tunnels and runways with zinc phosphide bait.
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Protect Seedlings: Use cutworm collars around seedlings to prevent cutworms from severing tender young stems and transplants. Check regularly for new damage.
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Handpick at Night: Search for cutworms near plant bases at night using a flashlight and remove them by hand. Drop in soapy water.
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Encourage Natural Predators: Promote cutworm predators like birds, predatory beetles, and parasitic wasps by avoiding pesticide use in your garden habitat.
By taking a proactive, multi-pronged approach and utilizing preventative measures tailored to each pest, you can gain the upper hand against these destructive critters attacking your plants’ stems. Pay close attention and quickly treat any damage to safeguard your garden from further assault. With persistence and vigilance, you can protect your landscape plants and enjoy their beauty.
Large Holes, No Excrement Visible
Next on my list of how to identify what’s eating your plants is if you notice large holes chewed in the leaves of your crops, but you don’t see any excrement nearby. In other words, you don’t see anything that the insect left behind.
The problem could be several different things. You could be dealing with a beetle, earwig, slug, snail, or grasshopper. These types of pests are often visible during the day and you can find them by looking underneath the leaves of your crops.
There are also times when these insects can only be seen at night. In order to properly identify them, you may want to go in your garden at night with a flashlight when most insects are feeding.
Tip #2: Use A Magnifying Glass
Some garden pests are very small, and using a magnifying glass will help you locate what is eating your plants. Sometimes, you’re going to see the damage with your naked eye, so having a magnifying glass will help you see the actual insect, too.
WHAT IS EATING MY PLANTS? | Common Garden Pest Control using Leaf Signatures
FAQ
How do I figure out what is eating my plants?
To investigate further, look for pests at dusk, or with a flashlight at night. Many caterpillars, beetles, and especially earwigs and slugs, feed at night and hide during the day. Handpicking caterpillars, beetles and slugs and dropping them into soapy water can be effective in home vegetable gardens.
What insect eats plant stems?
Some types, known as Cutworms, are bugs that eat plants through seedling stems at soil level, causing plants to keel over. Many Caterpillars boast camouflage that allows them to blend in with the leaves they are eating.
How to tell what animal is eating your plants?
- Deer – Ragged bites, typically a foot or more above the ground indicate deer damage. …
- Rabbits – If plant damage is low to the ground, a few inches above the soil, and includes stems clipped cleanly at an angle, the culprits are rabbits.
What are examples of plants that we eat stems?
Stems that we eat include potatoes and ginger, which are underground stems called tubers; asparagus, bamboo shoots, broccoli stems, kohlrabi, and sugar cane.
What eats my plants?
Another problem you might encounter when you are trying to identify what’s eating your plants is finding your plants are cut off at the soil line. You may notice that small seedlings you just planted are simply just gone, or tipped over. Cutworms are usually the culprit. Cutworms like to chew your plants right at the soil line.
What insects eat plants?
True bugs are insects in the order Hemiptera. These pests have piercing mouthparts they use to suck plant juice. However, not all plant-eating insects destroy vegetation by sucking sap. Types of true bugs in the order Hemiptera that eat plants include aphids, stink bugs, mealybugs, and scale insects.
How do you know if a plant eats a chewing insect?
Signs of chewing insect activity include: Ragged leaf holes: Chewing insects usually are not methodical and leave ragged holes in plants, especially insects that feed on vegetable leaves. Yellowing leaves: The leaf damage by chewing insects may also cause leaves to wilt and turn yellow.
How do you know if a pest eats your garden?
Sometimes, you’re going to see the damage with your naked eye, so having a magnifying glass will help you see the actual insect, too. Get outside in your garden at nighttime, armed with a flashlight. Often this will be the only time that you will see the pest that is eating your plants.
What eats seedlings at night?
Cutworms: The Nighttime Seedling Snatchers Cutworms are sneaky night critters doing their dastardly deeds under the cover of darkness. These moth larvae emerge from winter hiding spots to feast on young seedlings and tender new plants. By morning, you might find your plants chewed off right at the soil line—just little stubs left behind.
How do you know if a plant eats bugs?
This way, you can learn about the bugs’ habitat and behavior patterns to ensure that bugs in the garden don’t become an uncontrollable nuisance. One of the problems with identifying plant-eating bugs is that the holes seem to appear out of nowhere. Some pests that eat plant leaves only feed at night when their destructive behavior goes unnoticed.