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Identification and control methods of the licorice seed weevil

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Morphological characteristics: The adult is oval, brown or dark brown, with a body length of 2.5-3mm and a width of 1.5-1.8mm; the antennae are broad and short, serrate, and do not reach the base of the elytra. The pronotum is covered with punctures and dense light brown hairs, and its posterior margin is as wide as the elytra. The elytra are covered with punctures and dense light brown hairs. The pygidium is long, slightly pointed at the tip, and the ventral surface is covered with dense light brown hairs. The inner margin of the hind femur has 1 small, indistinct tubercle near the tip; the inner margin of the hind tibia has 1 long tooth at the tip; the first segment of the hind tarsus is the longest. Damaged crop: licorice. Damage symptoms: main

Morphological characteristics: The adult is oval, brown or dark brown, with a body length of 2.5-3mm and a width of 1.5-1.8mm; the antennae are broad and short, serrate, and do not reach the base of the elytra. The pronotum is covered with punctures and dense light brown hairs, and its posterior margin is as wide as the elytra. The elytra are covered with punctures and dense light brown hairs. The pygidium is long, slightly pointed at the tip, and the ventral surface is covered with dense light brown hairs. The inner margin of the hind femur has 1 small, indistinct tubercle near the tip; the inner margin of the hind tibia has 1 long tooth at the tip; the first segment of the hind tarsus is the longest.

Damaged crop: licorice

Damage symptoms: It mainly feeds on licorice seeds after harvest. For untreated new seeds, the insect infestation rate can reach 35% after overwintering, and the infestation rate of seeds stored for 2 years is above 70%.

Taxonomic attributes: Coleoptera, Curculionidae

Occurrence characteristics: 1 generation occurs each year, and it overwinters as larvae in stored licorice seeds and in the pods of licorice plants in the field. Eclosion begins in mid-May of the following year, and adults can be seen in the field from late May to late September, with the highest field population density in early August. Adults lay eggs on growing pods, and after the larvae hatch they develop inside the seed pods and overwinter with the seeds in warehouses or in pods left in the field. Adults can feed on licorice leaves, while larvae mainly damage stored licorice seeds.

Control methods: In autumn, thoroughly cut down wild licorice plants in and around the plantation. During the pod-setting stage, spray once with 90% trichlorfon crystal at 1000 times dilution and 20% deltamethrin emulsifiable concentrate at 2000 times dilution. After the licorice seed pods are harvested and threshed, when the seeds are put into warehouse storage, the seeds can be treated by fumigation with aluminum phosphide; for large-volume storage, sealed oxygen-removal and nitrogen-filling storage is best. During storage, regular inspections should be carried out; when insects are present, fumigate again with aluminum phosphide.

Commonly used pesticides: trichlorfon, 20% deltamethrin emulsifiable concentrate

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