Spodoptera exigua
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September 17 08:02:24, 2025
Amphipoea fucosa (Freyer), commonly known as the nightingale moth, is a significant pest in various wheat-growing regions of China. It belongs to the order Lepidoptera and is widely distributed across the northeast, north, northwest, the Tibetan Plateau, the middle and lower reaches of the Yangtze River, and eastern China. This pest causes considerable damage to spring wheat, with general yield losses ranging from 10% to 20%, and severe infestations can reduce yields by up to 40% to 50%.
The larvae of A. fucosa feed on a variety of grass crops, including wheat, barley, alfalfa, and wild oats. They are particularly active in irrigated fields, wetlands, and clay soils. Before reaching the third instar, they bore into the stems of wheat plants, causing internal damage. Once they enter the fourth instar, they move to the base of the wheat stalks, feeding on the roots and creating tunnels in the soil. This behavior leads to symptoms such as "dead heart" or complete plant death, resulting in poor stand establishment and reduced grain yield.
Adults have a body length of 13–16 mm, with wings spanning 30–36 mm. Their coloration includes a yellow-brown head and thorax, a gray back, and a yellow-brown abdomen. The forewings display five distinct brown lines, with a white to rust-colored kidney-shaped spot and fine dark lines along the edges. The hind wings are gray-brown with yellowish margins. Eggs are semi-circular, initially white, and turn brown after a few days. Mature larvae measure 30–35 mm, with a grayish-white body, a yellow head, and dark brown markings along the back. They have red-brown stripes and two tail hooks at the end of the abdomen.
In the North Spring Wheat Region, A. fucosa completes one generation per year. Eggs overwinter and hatch in mid-May of the following year. Larvae begin feeding on wheat seedlings in late May, entering the stem during the tillering stage. By late June, the larvae mature, and adults emerge in mid-July. The peak of adult activity occurs in mid-August. Female moths lay eggs on the base of wheat stems, 1–3 cm above the soil surface, typically between 20:00 and 21:00. Each female lays 90–400 eggs in clusters of 2–3 rows, with about 30 eggs per row. The egg-laying period lasts 5–8 days.
Larvae are subterranean pests that undergo five molts, with a development period lasting over 50 days. After reaching maturity, they pupate within 1–3 cm of the soil near infected plants, and the pupal stage lasts approximately 20 days.
To manage this pest, several control methods are recommended. Crop rotation and deep plowing help eliminate eggs from the soil. Watering during the three-leaf stage of wheat can drown newly hatched larvae. Adult moths can be trapped using black light traps before they lay eggs. In heavily infested areas, granular insecticides like 4% phoxim or 0.5% thiophosphorus can be applied at a rate of 2–3 kg per 667 m², achieving over 80% control of newly hatched larvae. During the larval stage, solutions of 80% trichlorfon or 36% chlorpyrifos emulsifiable concentrate can be used for root application. These integrated approaches help reduce damage and protect wheat yields effectively.