Symptoms, incidence regularity and control methods of orchid leaf spot

Orchid is one of the varieties that people like to grow. Orchids cultivated at home have light fragrance, self-cultivation, combination of work and rest, and leaf spot is one of the orchid diseases.

First, symptoms: Chunlan infected, the primary brown-black near-round or oblong spots on the leaves, and then gradually expanded into irregular long disease spots, the junction of the healthy tissue was obvious, the disease spots were black around, gray-white in the middle, and small black spots were produced on the front of the leaves in the later stage, that is, the pathogen conidium.

Second, the regularity of the disease: the pathogen overwintered on the diseased leaves with conidia, and the conidia were transmitted by wind and rain in the following year for primary infection. The temperature is 25 ℃ and 27 min. It is easy to get sick after rain, and the plaque is sometimes perforated.

Third, prevention and control methods: (1) careful maintenance, pay attention to improve the maintenance conditions of orchids, make it ventilated and transparent, and water it after the sun comes out in the morning. (2) spraying 50% carbendazim wettable powder at the initial stage of the disease, or 50% thiophanate methyl wettable powder and 37% difenoconazole water dispersible granule 3000 times.