Gray mold

Symptoms: In Taiwan, China, from February to April, when outdoor humidity is low but indoor humidity is high, or when it rains, flowers are easily infected by this disease, especially Cattleya orchids and Phalaenopsis orchids, which are the most obviously affected. At first, small brown spots appear on the petals, and in severe cases the petals wither. Control methods: 1. After May, as the temperature gradually rises, this disease naturally gradually decreases. 2. When diseased spots are found on the petals, daytime ventilation should be strengthened to reduce indoor humidity. 3. For routine prevention, use 25% triadimefon emulsifiable concentrate at 1500 times dilution, 50% mancozeb wettable powder at 500 times dilution, 50% carbendazim powder at 500 times dilution, thiophanate-methyl at 1500 times dilution, or captan at 1000 times dilution, and spray regularly. 4. For treatment, 50% dicloran at 1000 times dilution, 50% mancozeb wettable powder at 500 times dilution, or 80% zineb wettable powder at 500 times dilution can be used, sprayed once a week. (Xue Congxian)