Large yellow underwing

The Large yellow underwing (Noctua pronuba) is a moth of the family Noctuidae. It is one of the most common and widely distributed moth species in Europe and parts of North America. The adult moth is characterized by its dull brownish-grey forewings, which serve as excellent camouflage when resting, and striking bright yellow hindwings with a broad black border, which are only revealed during flight or when the insect is disturbed.

This species is a polyphagous pest, meaning it feeds on a wide range of plant species. The caterpillars are known to attack various agricultural and horticultural crops, including lettuce, cabbage, carrots, potatoes, and ornamental plants. Due to their varied diet, they can thrive in both field conditions and home gardens, often causing damage to young seedlings by severing them at the base or devouring the foliage entirely.

The life cycle typically consists of one generation per year. Adults are nocturnal, active from late spring to autumn. Females lay clusters of eggs on the underside of leaves or on the soil surface. After hatching, the larvae go through several instars. The caterpillars are nocturnal feeders, spending their days buried in the soil or hiding beneath dense plant debris. They overwinter in the larval stage deep in the soil, which helps them survive colder temperatures.

The damage caused by the larvae can be devastating, especially to young plants. Early instars skeletonize the leaves, while later stages consume entire leaf blades, stems, and sometimes even roots or tubers. High larval density can lead to total crop failure. Because the caterpillars are nocturnal and hide during the day, farmers often notice the damage only after the pest has significantly affected the plant population, making early scouting essential.

• Implement deep autumn plowing to expose overwintering pupae to predators and frost.
• Keep fields and garden borders free from weeds that serve as alternative hosts.
• Monitor moth activity using light or pheromone traps to time interventions.
• Apply biological insecticides, such as products containing Bacillus thuringiensis, while larvae are small.
• Utilize crop rotation to break the life cycle of the pest in high-risk areas.