Mycosis-orchid flower blight

① Fusarium wilt (Fusarium flower blight)

Distribution: worldwide.

Pathogen: Fusarium moniliforme

Host: Arachnis, Dendrobium

Symptoms: whole flowers or inflorescences, especially buds, are susceptible to infection. The infected part is a sunken dark brown to black spot, usually covered with white powder (mycelium) and small pink spores. Severe infection can cause flowers to turn yellow and wither in the bud stage.

Prevention and treatment: cut off diseased flowers. Spray 80% Dyson zinc or 80% Daimen manganese wettable powder 400ml 60O every 4 to 7 days. You can also use 50% carbendazim.

Wettable powder 5O0 doubly sprays and irrigates the soil.

Note: can also infect leaves, known as Fusarium leaf spot (Fusarium leaf spot), that is, the emergence of small spots, more common in injured tissue.

② grape spore flower blight (Botrytis blossum blight)

Distribution: worldwide; more common in the United States.

Pathogens: Botrytis cinerea and other species of the genus.

Hosts: Cartland (Cattleya), Cymbidium (Orchid), Dendrobium (Dendrobium), Paphindilum (Orchidaceae), Pha-laenopsis (Phalaenopsis), Spathogottis (Orchid), Vanilla (Vanilla) and so on.

Symptoms: light brown, very small water stains appear on the perianth. This spot will enlarge and cause the whole flower to rot. Vanilla fruit deformation disease is also caused by this pathogen.

Prevention and treatment: the infection rate in humid environment is high, so it is necessary to reduce the humidity appropriately, especially at night. First cut off the infected flowers, and then spray them with 80% Daimen zinc-manganese wettable powder 400 × 600 times or 50% carbendazim 500 times 800 times, once every 10 to 15 days, with good results. But you can't use carbendan to avoid hurting the flowers.

Note: this disease is very common. Different orchids are infected with different names, such as Dendrobium flower blight (Dendrobium blossum blight), flower brown rot (Flower brown rot), flower brown spot (Flower brown speck), flower leaf spot (Flower spock), flower spot (Fiower spotting), petal blight (Petal blight), petal leaf spot (Petal speck), gray mold (Graymoid) and so on.

③ Curvularia flower blight (Curvularia flower blight)

Distribution: worldwide.

Pathogen: hrvuLaria genicula-ta.

Parasitism: a variety of orchid cut flower hybrids.

Symptoms: ovate or round plaques about 0.5mm wide appear on sepals, petals (one or both sides) or pedicels, slightly concave, light brown to dark brown.

Prevention and treatment: same as anthrax prevention and control method.

Note: it can also infect damaged leaf tissues, such as the leaves of many hybrids of Dendrobium (Dendrobium nobile).

Chen Xinqi Ji Zhanhe