Symptoms and Control Methods of Snow Mold in Orchids

Distribution: Asia, also in greenhouses in the United States. Pathogen: some species of the genus Ptychogaster. Hosts: Vanda and other closely related genera that do not have pseudobulbs. Symptoms: white powder appears on the growing medium or soil, and even at the base of the plant stems or spreading to other parts. Control: This pathogen is not parasitic onorchids, but instead lives on the potting soil, consuming nutrients and water, affecting air circulation, and thereby harmingorchids. Therefore, it is necessary to remove the infected potting soil and mix 40% quintozene or 50% carbendazim at 5-6 g/sq m with fine soil before incorporating it into the soil. The plants should also be rinsed. (Chen Xinqi, Ji Zhanhe)