How should reishi mushroom bridge worms be prevented and controlled?

The reishi mushroom bridge worm (scientific name to be determined) belongs to the order Lepidoptera, family Geometridae. This pest damages reishi mushroom fruiting bodies. Young larvae feed on the surface and edges of the cap, causing pits and notches. After the 3rd instar, they can bore directly into the interior of the fruiting body and excrete large amounts of frass, which not only contaminates the mushroom bodies but also encourages the proliferation of weeds such as green mold, harming reishi mushroom growth and reducing yield and impairing quality.

(1) Morphological characteristics. Adult: body length 12 mm, wingspan 25-28 mm, body grayish black; antennae filiform, outer margin of forewing with 8 small black spots, a larger black spot in the middle of the costal margin, hindwing grayish white. Egg: oblate, height 0.6-0.7 mm, transverse diameter 0.4-0.5 mm. Newly laid eggs milky white, turning grayish green before hatching. Larva: mature larva body length 22-25 mm, head black, body grayish yellow, body surface with dark brown wart-like protrusions, and after entering the 4th instar the body segments have yellowish brown markings. Two pairs of prolegs, located on the 6th abdominal segment and the anal segment, walking in an arched bridge shape, like a finger measuring an object. Pupa: body length 11-14 mm, spindle-shaped.

(2) Occurrence pattern. July to August is the peak period of pest population occurrence, and the damage to reishi mushrooms is most severe at this time. According to Jiang Shicha's report, for reishi mushrooms cultivated in open fields with small sheds covered by film and straw curtains, the bag damage rate for those cultivated in early July reached 13.3%, and the bag damage rate for those cultivated in early August reached as high as 42%; the damage rates for indoor and large shed cultivation were 6.2% and 8.5% respectively.

(3) Control methods. 1. Install screen windows and screen doors at ventilation openings to prevent adults from flying in to lay eggs. 2. Chemical control: Bacillus thuringiensis (abbreviated as B.t) added to a 1 in 10,000 mixture of juling hezhi compound agent at 1000 times dilution achieved a control efficacy of 94.8% against larvae. Juling hezhi at 1000 times dilution achieved a control efficacy of 100%.