Symptoms and prevention of Phalaenopsis gray mold

Phalaenopsis gray mold symptoms identification

It mainly harms the flowers, pedicels, leaves, sepals and other parts of orchids. When the leaves are damaged, brown lesions will appear unevenly distributed on the back of the leaves, which will affect the photosynthesis of the leaves and cause poor growth of orchids. The petals and calyx are infected with the bacteria. Initially, water-soaked, translucent small spots appear on the petals and calyx, and then the spots turn brown and gradually expand into circular patches, and the spots merge with each other. After the disease occurs, the entire flower turns dark brown with pink edges, rots and withers. When the pedicels are attacked by the pathogen, small water-like spots appear in the early stage, which gradually develop into dark brown oval spots. About a week later, the flowers will wither and die. Orchids that are attacked early will have their flowers withered early and the buds dry up. Orchids that bloom early are most susceptible to gray mold.

Phalaenopsis gray mold disease pattern

Phalaenopsis gray mold prevention and control methods

1. Choose the cultivation medium

Phalaenopsis has epiphytic roots and fleshy aerial roots. Therefore, the substrate should be well-ventilated and have fertilizer-retaining properties. Commonly used substrates are aquatic plants, coconut bran, pine bark, etc. The base fertilizer should be well-rotted farmyard manure, which can be slowly absorbed by the roots. Liquid fertilizer is commonly used, diluted 1500 to 2000 times. Orchids grown in such a medium are strong and rarely diseased.

2. Pay attention to the cleaning of the orchid room

Pay attention to hygiene in the area where you grow orchids, and try to remove dead branches and rotten leaves around them. When winter comes, move your orchids indoors. When moving back, clean the room in advance, then remove the diseased flowers and leaves and disinfect with lime water to reduce the base number of pathogens as much as possible.

3. Strengthen management

When cultivating orchids, you must strengthen management and carefully care for them, pay special attention to changes in indoor temperature and timely adjustments, and pay close attention to the growth of orchids. Check regularly and if you find diseased flowers and leaves, take timely measures to seal the diseased orchids with plastic bags and take them outdoors together with the pots for disposal. Do not put them back into the greenhouse to reduce infection by pathogens. Provide appropriate windproof measures according to weather conditions.

4 Early stage of disease

Spray the entire pot with carbendazim to disinfect and sterilize. When placing orchids, do not seal them. There should be a certain distance between pots to prevent infection, and allow ventilation and light to pass through to prevent water accumulation, which will increase indoor humidity. In daily orchid management, pay attention and be careful to minimize orchid wounds and prevent pathogens from invading through the wounds.

5. Chemical control

Agents such as carbendazim and thiophanate-methyl can treat gray mold and are available at ordinary flower shops. When applying the drugs, be sure to use them in rotation to prevent the development of drug resistance.