Disease control measures of orchid leaf blight and topdressing methods of edible fungi

Symptoms mainly occur on orchid leaves, the initial disease spots are black-brown, nearly round, and the disease spots occurring at the leaf margin are semicircular; then they quickly expand into oval large spots, the diameter can reach more than 20 mm, the edges are black-brown, the center gradually becomes light brown, sometimes there are one or two rings of light color ring patterns.

Control a, strengthen cultivation management: greenhouse ventilation and light transmission, flowerpot placement should not be too dense, potted plants should be replaced with new soil. b. Remove the infection source: remove the diseased leaves and their residues in time to eliminate the infection source and prevent the spread of the disease. c. Chemical control: 0.5~1% Bordeaux mixture or 65% Zineb wettable powder 600~800 times can be sprayed once every 7~10 days before the disease occurs, which has a good protective effect. During the disease period, 50% carbendazim 800 times solution or 75% thiophanate-methyl 1000 times solution can be sprayed, which can control the spread of the disease.

The fungus overwinters on diseased leaves and their remains and spreads by rain and water. Generally from the wound invasion, young leaves can also be directly invaded. In the appropriate temperature and humidity conditions, bacteria can spread disease. Soil hardening, potted plants placed too dense, poor ventilation are easy to disease.