Black Cutworm

Agrotis ipsilon

1. Identification

• Common name: Black cutworm
• Scientific name: Agrotis ipsilon Hufnagel
• Order: Lepidoptera
• Family: Noctuidae

2. Pest description

• Caterpillars of a dark grey to almost black colour, with a smooth, glossy body, reaching 40–50 mm, curling into a “C” shape when disturbed.
• Adults with a 40–55 mm wingspan, dark brown forewings with discreet patterns and pale hindwings.
• Highly polyphagous species, attacking a wide variety of crops, especially at early stages.
• Caterpillars live in the soil and feed at the collar level of the plants, cutting them partially or completely.
• It may have several generations per year, with greater activity in spring and summer.

3. Main hosts

• Maize, tomato, pepper, potato, beet, carrot and other vegetable crops.
• Industrial crops such as tobacco, cotton and sunflower.
• Various weeds can serve as a reservoir.

4. Symptoms and damage

• Cutting of seedlings at soil level, causing planting gaps.
• Young plants toppled or partially gnawed at the base.
• Superficial borings in roots and tubers.
• Severe damage in seedbeds and transplants, which may compromise crop establishment.

5. Biological cycle

• Eggs laid in the soil or at the base of the plants.
• Caterpillars develop in the soil, where they remain throughout the larval cycle.
• Pupation also in the soil, at variable depths.
• Adults with nocturnal activity, attracted to light, with intense flights during warm periods.
• Development favoured by moist soils and high temperatures.

6. Monitoring

• Observation of plants cut at soil level in seedbeds and transplants.
• Superficial digging next to affected plants to detect caterpillars.
• Light traps to detect adults and track flights.
• Pheromone traps to monitor population peaks.
• Assessment of the percentage of affected plants at the early stages of the crop.

7. Management measures

• Cultural: superficial soil tillage to expose caterpillars and pupae, removal of weeds, proper management of organic matter and choice of sowing periods less favourable to the pest.
• Preventive: use of more developed plants at transplanting, practices that promote good rooting and maintenance of soil conditions that hinder caterpillar survival.
• Biological: conservation of natural enemies such as ground beetles and insectivorous birds, and use of selective biological products such as Bacillus thuringiensis at early stages.
• Integrated protection: monitoring with pheromones and light traps, definition of intervention thresholds and careful application of authorised insecticides targeting the soil and the most sensitive stages of the pest.

Bibliographic references

• CABI – Invasive Species Compendium – Agrotis ipsilon.
• EPPO Global Database – Agrotis ipsilon.
• Capinera, J. L. (2001). Handbook of Vegetable Pests. Academic Press.
• Showers, W. B. et al. (1983). Ecology and behavior of black cutworm (Agrotis ipsilon). Annual Review of Entomology, 28, 289–312.
• Lafontaine, J. D. (2004). Noctuoidea of North America. Canadian National Collection of Insects.