A Detailed Guide to Identifying and Controlling Common Pests of Shiitake Mushrooms

1. Mites, commonly known as fungus lice, are divided into two types: flour mites and straw itch mites. Straw itch mites are small and difficult to see with the naked eye; they tend to gather in clusters on the surface of the growing substrate. Flour mites are larger, white and shiny, do not form clusters, and appear powdery when numerous. On shiitake mushroom blocks infested by mites, the mycelium is gnawed on, and in severe cases the mycelium can be eaten completely.

If mites occur in the spawn, a cotton plug dipped in 50% dichlorvos can be inserted to fumigate and kill them. If mites appear during the mycelium-running stage, they can be killed by spraying 0.5% dichlorvos, or by spraying a 2000-fold dilution of 25% permethrin-ester compound. If mites occur during the fruiting stage, they can be killed by spraying permethrin-ester compound, but mushrooms may only be harvested 3 days after spraying.

2. Fungus gnats: their young larvae feed inside the growing substrate, while older larvae bore into and feed on the fruiting bodies of shiitake and other mushrooms.

Control methods: keep the mushroom house, mushroom yard and surrounding environment clean and hygienic. Before cultivation, the mushroom house and mushroom yard should be sprayed with insecticide, using a 1000-1500-fold dilution of 40% dichlorvos. If fungus gnats occur during the fruiting stage, they can be killed by spraying a 1000-1500-fold dilution of 40% dichlorvos, or a 2000-fold dilution of 25% permethrin-ester compound can be sprayed on the surface of the substrate for control.

3. Gall midges: their larvae mainly damage the mycelium and fruiting bodies; the control methods are the same as those for fungus gnats.

4. Springtails, also known as snow fleas, soot worms, etc. Control methods: spray a 500-fold dilution of 40% dichlorvos inside and outside the cultivation room and in the mushroom yard. If springtail damage occurs during the mycelium-running stage, dichlorvos plus honey can be used as a poison bait: spray a 500-fold dilution of 40% dichlorvos onto paper, then drip a few drops of honey on it, and spread the poisoned paper in separate pieces on the surface of the growing substrate to lure and kill them. If springtail damage occurs during the fruiting stage, 0.1% derris extract or pyrethrum can be used to kill them.

5. Nematodes: when damaged by nematodes, the surface layer or the entire growing substrate becomes wet, blackened and sticky, and the mycelium shrinks or disappears, while young mushrooms die. Dead young mushrooms have a sticky surface and a fishy odor. Under humid, stuffy and poorly ventilated conditions, nematode damage is likely to occur. Control methods: spray a 2% formaldehyde solution to kill them. When nematode damage occurs on part of the growing substrate, the affected portion of the nutrient substrate can be dug out and sprayed with formaldehyde to kill them.

6. Slugs, also known as snot worms, are a type of mollusk. They hide in dark, damp places during the day and come out at night to feed on the fruiting bodies of shiitake and other edible mushrooms. At 9-10 p.m., when slugs come out to move about, they can be caught by hand, or a 1% potassium permanganate solution or 5% salt solution can be sprayed in the places and along the routes where they move, for control.

7. Termites mainly damage mushroom wood. Control methods: mix 80% arsenious acid, 15% salicylic acid and 5% ferric chloride into a poison, and spray it on termite trails and nests, spraying 6-16 ml per nest; or mix 50% mercuric chloride, 35% arsenious acid, 10% salicylic acid and 5% ferric chloride into termite powder and spray it on the nests, so that as long as some termites pick up the poison, the entire nest can be wiped out.