Identification and Control Methods for Dactylium cobweb disease in lingzhi (Ganoderma)

DactyliumdendroidesFries belongs to the subdivision Deuteromycotina, class Hyphomycetes, order Moniliales, family Moniliaceae, genus Dactylium.

1. Morphological characteristics: The hyphae are pure white and cottony. The conidiophores are slender and sparse, with whorled branches arranged in a radiating pattern. The conidia are oblong, colorless, borne at the tips of sterigmata, solitary or in small clusters, mostly with 4 cells.

2. Disease development pattern

(1) Transmission route: Dactylium lives in soil and is widely distributed in soils rich in organic matter. When lingzhi (Ganoderma) is cultivated with casing soil, the disease pathogen is easily transmitted if the soil has not been sterilized.

(2) Conditions for occurrence: High temperature, high humidity, poor ventilation and excessively thick casing soil are the main conditions for the occurrence of this disease.

3. Damage symptoms: This fungus locally produces white cottony hyphae on the surface of the casing soil, then rapidly spreads to form a layer of white mycelial mat 1-2 cm thick that covers the bed surface. The stipes of the affected lingzhi (Ganoderma) are invaded by the slender hyphae, causing the base of the stipe to become water-soaked and rot, forming yellowish-brown or light-brown soft rot symptoms, which inhibits the normal development of the fruiting bodies.

4. Control methods

(1) Before casing, carry out fumigation treatment with a 5% formaldehyde solution.

(2) Use clean running water or tap water for mixing the substrate.

(3) In the early stage of infection, the mycelial mat can be locally scraped off and lime powder sprinkled on, or a 2% formaldehyde solution sprayed on; strengthen ventilation and stop watering for 1-2 days.

(4) On the premise of not harming the growth of young lingzhi (Ganoderma), promptly remove the casing soil contaminated by foreign fungi and cover again with 1-2 cm of burned soil or sterilized treated soil.