The cutworm (Family: Noctuidae) is a soil-dwelling caterpillar that is one of the most destructive pests for young seedlings. These nocturnal insects feed at night, severing seedlings at ground level and causing sudden, unexplained plant death. They are most active in spring and early summer, and their damage can be devastating for newly planted crops, particularly leafy greens like Swiss chard, spinach, and lettuce. Understanding their life cycle, behavior, and management is essential for protecting vulnerable seedlings.
Written by Kutlwano Mokoena
Founder of Evergreen Hideout Agricultural Services (NPO: 2024 / 380375 / 07). Specialist in organic pest management and soil biology.
Quick Diagnostic Summary
Seedlings cut off at ground level, found lying flat. The stem is cleanly severed — a signature sign of cutworm damage.
Fat, greasy-looking caterpillar that curls into a C-shape when disturbed. Found just below the soil surface near damaged plants.
🐛 First Encounter: The Fallen Seedling
This encounter happened during our garden expansion at Raikana Primary School. Me and my friend and colleague Emnes Baloyi were working together — we push two brands on the same garden: mine is Evergreen Hideout, his is Alkemetic Vegetation Garden. We've decided to expand the garden and plant more Swiss chard spinach and sell them, like we used to in Alkemetic Vegetation Farm.
We planted new seedlings and used chicken compost, like we usually do. We often get to the garden early in the morning. When we arrived, Emnes was checking the other side of the seedlings, and I was checking the other side. That's when I found it — a seedling was laying flat on the ground.
What I observed: The seedling was completely severed at ground level. My immediate thought was armyworms — but armyworms usually feed on cabbage and kale, not Swiss chard. I dug around the spinach plant, just below the soil surface, and there it was — a fat, greasy-looking caterpillar curled into a C-shape. It was a cutworm.
I knew then what had happened. These insects are said to eat seedlings at night. The day before, the seedling was sitting upright — healthy and strong. We normally knock off around 2pm, so it couldn't have destroyed my spinach during the day. I assumed that worms don't like the sun, and they travel underground to avoid it.
🐛 Personal Connection: This was my first real encounter with cutworms. I had heard of them, but I had never seen one. It was frustrating — we had put so much work into those seedlings. But it was also a lesson. I realised that the garden is always teaching us something, and that pests are part of the system.
I shared what I found with Emnes. We both knew that this wasn't the end — we would replant and protect the new seedlings. That's what gardeners do: we learn, adapt, and keep growing.
This sighting was significant for three reasons:
- Discovery of a major pest: I learned that cutworms are a serious threat to young seedlings, particularly Swiss chard and spinach.
- Confirmation of nocturnal behavior: The seedling was healthy the day before and destroyed overnight — confirming that cutworms feed at night and hide in the soil during the day.
- Lesson in observation and adaptation: This experience taught me to inspect seedlings carefully, dig around damaged plants, and take action to protect future plantings.
📍 Location: Raikana Primary School, Soshanguve, Pretoria
📅 Date: July 2026
🌤️ Conditions: Early morning, Swiss chard seedlings, chicken compost used
🌱 Encounter context: Expanding the garden with Emnes Baloyi; found a Swiss chard seedling flat on the ground; dug around and found a cutworm curled in the soil
Identification: The Soil-Dwelling Caterpillar
Cutworms are the caterpillars of various moths in the Noctuidae family. They are named for their habit of "cutting" seedlings at ground level.
Key identification features:
- Appearance: Fat, greasy-looking caterpillars. They are typically grey, brown, or black with a smooth skin.
- Behaviour: When disturbed, they curl into a C-shape as a defensive response. They are inactive during the day and feed at night.
- Hiding spots: They hide just below the soil surface, under plant debris, or in soil cracks during the day.
- Size: 2–5cm in length, depending on the species and instar stage.
- Damage: Seedlings are severed at ground level, often leaving the stem cleanly cut. The damaged plant is found lying flat on the soil.
Life Cycle and Nocturnal Behavior
Cutworms undergo complete metamorphosis — egg, larva (caterpillar), pupa, and adult (moth). The life cycle typically takes 4–6 weeks, depending on temperature and food availability:
- Eggs: Laid in clusters on plant stems or in the soil near host plants.
- Larvae (cutworms): The destructive stage. Feed at night, hiding in the soil during the day.
- Pupae: Develop in the soil, emerging as adult moths.
- Adults (moths): Brown or grey moths that are active at night.
Nocturnal behavior: Cutworms are active at night, emerging from the soil to feed on seedlings. They feed on a wide range of plants, including Swiss chard, spinach, lettuce, tomatoes, and brassicas. They are most active in spring and early summer.
Damage and Management Strategies
Cutworm damage is characterized by seedlings that are cleanly severed at ground level. The cut stem is often found lying on the soil surface, while the roots remain intact below ground.
Organic management strategies:
- Monitoring: Inspect seedlings daily, especially in the morning. Look for seedlings that are wilting or lying flat.
- Hand removal: Dig around damaged seedlings to find and remove the cutworm. Dispose of them in soapy water.
- Cardboard collars: Place a collar around each seedling, extending 2–3cm into the soil. This creates a barrier that cutworms cannot pass.
- Companion planting: Plant herbs like mint, garlic, or onion near vulnerable crops to deter cutworm moths from laying eggs.
- Biological control: Encourage natural predators such as ground beetles, birds, and parasitic wasps.
- Soil preparation: Turn the soil before planting to expose cutworms to birds and predators. Remove plant debris that provides shelter.
Frequently Asked Questions
Q: What are cutworms?
A: Cutworms are the caterpillars of night-flying moths. They are soil-dwelling pests that feed on seedlings at night, severing them at ground level.
Q: How can I tell if I have cutworms?
A: Look for seedlings that are cut off at ground level and lying flat on the soil. Dig around the base of the damaged plant — you may find a fat, greyish-brown caterpillar curled in a C-shape.
Q: What plants do cutworms attack?
A: Cutworms attack a wide range of plants, including Swiss chard, spinach, lettuce, tomatoes, peppers, brassicas, and beans.
Q: Are cutworms active during the day?
A: No. Cutworms are nocturnal — they feed at night and hide in the soil during the day. This is why the damage is often discovered in the morning.
Q: How can I protect my seedlings from cutworms?
A: Use cardboard collars around seedlings, monitor daily, hand remove cutworms, and encourage natural predators. Avoid planting in areas with heavy plant debris.
📚 Related Resources
- Real Grow Series: Follow the full journey of building a food-producing garden from scratch — Start here
- Swiss Chard Update: Mid-season growth audit and harvesting
- Companion Planting: Using plants to deter pests and attract beneficial insects
- Organic Pest Management: Non-chemical solutions for common garden pests
Conclusion: The Night-time Assassin
The cutworm is a reminder that not all pests work in the open. Some of the most destructive garden enemies are active when we're asleep, hiding in the soil during the day and emerging at night to feed on our crops.
My encounter with the cutworm at Raikana Primary School — in partnership with Emnes Baloyi — taught me that vigilance is key. By checking seedlings regularly, digging around damaged plants, and taking action early, we can protect our crops and keep the garden productive.
We replanted those Swiss chard seedlings, and we'll keep watching. That's what gardening is — a constant cycle of learning, adapting, and growing.