Prevention and Control of White Silk Disease of Cymbidium

Symptom

The rhizome near the ground showed water-stained yellow-brown to reddish-brown wet rot, the leaves were easily pulled away, the diseased part had obvious white mycelium and rapeseed-like sclerotia, and the plant wilted and died.

Disease condition

Plants planted in bacteria-carrying soil are easy to occur in hot, rainy and humid summer. The disease can occur early under the hot and humid conditions in the greenhouse.

Pathogen

SclerotiumrolfsiiSacc. Belongs to the fungal half-known subphylum, non-spore order, Sclerotinia genus, neat small nucleus. The hyphae are white, silky and radiate on the substrate, with septum, sclerotia spherical, oval, 0.5-1.0 mm in diameter, large 3 mm, smooth and glossy, initially white, and then brown.

Route of infection

The pathogen overwintered mainly as sclerotia in the soil, and could also survive on the diseased remains as mycelia. Sclerotia directly produce hyphae and spread along the cracks in the soil gap.

Prevention and control methods:

1. Chemical prevention and control:

1.50% fluxone wettable powder 1000 times.

2.5% Fodonine wettable powder 3000 times.

3.75% metoprolol wettable powder 1000 times (the solution should be sprayed and the cultivation substrate should be sprayed, and the water spraying should be stopped for 5 days after spraying).

Second, after discovering the white silk disease, the diseased leaves, diseased plants and nearby plants should be removed and burned, and the nearby plants should be sprayed with control agents more than three times immediately.

Third, before planting, the medium is disinfected with steam, or covered with 0.6% urea for one week.