Turnip Moth

Agrotis segetum

Caterpillars greyish-brown to dark-brown in colour, with a smooth, shiny body, reaching 40–45 mm, curling up into a “coil” shape when disturbed.
Adults with a 35–45 mm wingspan, brownish forewings with discreet markings and paler hindwings.
Polyphagous species that attacks various horticultural and industrial crops, with caterpillars that live in the soil and cut plants at the collar level.
Adults attracted by light that lay their eggs in the soil, preferring moist soils.
It may have 2 to 3 generations per year, depending on the climatic conditions.

Cutting of the seedlings at soil level, causing immediate death and planting gaps.
Young plants uprooted or toppled due to the feeding of the caterpillars on the collar.
Superficial perforations in root crops.
More severe damage in recent sowings and transplants, possibly requiring resowing or replanting.

Eggs laid in the soil, singly or in small groups.
Caterpillars develop exclusively in the soil, where they feed and remain until pupation.
Pupation also in the soil, with adults emerging in peaks in spring and late summer.
Development favoured by moist soils, mild temperatures and the presence of organic matter.

Observation of plants cut at soil level in sowings and transplants.
Superficial digging next to the affected plants for detection of caterpillars.
Light traps for detection of adults and monitoring of flights.
Pheromone traps for monitoring of population peaks.
Assessment of the percentage of affected plants in the early stages of the crop.

Cultural: removal of weeds, adequate soil preparation, reduction of fresh organic matter and superficial tillage that exposes caterpillars and pupae to natural predators; choice of sowing dates less favourable to the pest and use of more developed plants at transplanting.
Preventive: selection of establishment dates that avoid the population peaks, adoption of practices that favour good rooting of the plants and maintenance of soil conditions that hinder the survival of the caterpillars.
Biological: conservation of natural enemies such as ground beetles, rove beetles and insectivorous birds, and use of selective biological products such as Bacillus thuringiensis, effective above all in the young stages.
Integrated protection: monitoring with pheromones and light traps, definition of intervention thresholds suited to the crop conditions and judicious application of authorised insecticides targeted at the soil and at the most sensitive stages of the pest.

CABI – Invasive Species Compendium – Agrotis segetum.
EPPO Global Database – Agrotis segetum.
Finch, S. (1986). Assessing the pest status of the cutworm Agrotis segetum. Annals of Applied Biology, 109, 1–10.
Hill, D. (1987). Agricultural Insect Pests of Temperate Regions and Their Control. Cambridge University Press.
Keller, M. et al. (2004). Cutworm damage and management in field crops. Journal of Applied Entomology, 128, 157–166.