Occurrence and Damage Characteristics of the Bridgeworm Pest on Lingzhi

The bridgeworm (Noctuidea) belongs to the family Geometridae. The lingzhi bridgeworm of this family (name to be determined) is an important pest damaging lingzhi.

1. Morphology and habits: The adult is 12 mm long with a wingspan of 25-28 mm, a small grayish-black moth. The antennae are filiform; the forewings are triangular with 8 black spots along the outer margin and one larger black spot in the middle of the costal margin; the hindwings are grayish-white. The egg is flat and round, 0.6-0.7 mm long and 0.4-0.5 mm wide, milky white initially and grayish-green before hatching. The mature larva is 22-25 mm long, with a black head, a cylindrical grayish-yellow body, and dark brown protuberances on the surface; after entering the 4th instar, yellow-brown markings appear on the body segments. It has 3 pairs of thoracic legs and 2 pairs of prolegs, and moves in an arched, bridge-like posture. The pupa is 11-14 mm long, spindle-shaped, and brown.

The high-temperature period from July to August is the peak of pest population occurrence, causing the most severe damage to lingzhi. The egg stage lasts 7-9 days, the larval stage 23-25 days, the pupal stage 12 days, and the adult lifespan 5-6 days. Adults hide by day and emerge at night; females lay eggs on the lower surface edge of the lingzhi cap or at the junction between the cap and the stipe.

2. Damage situation: The larvae bore into and feed on the hymenial layer, causing groove-like damage, and more often feed on the tender outer edge of the cap, causing notches; in severe cases they bore into the interior of the fruiting body, seriously affecting the quality and yield of lingzhi.

3. Control methods

(1) Install screens on doors and windows to prevent adults from entering and laying eggs.

(2) Add Bacillus thuringiensis (Bt for short) to a 1000-fold pyrethroid pesticide mixture and spray to kill them.

(3) Use high-voltage electrostatic insect-killing lamps for trapping and killing.