How to effectively prevent and control anthracnose in orchids?
How to effectively prevent and control anthracnose in orchids?
In view of the many causes, the following integrated control measures must be adopted for the results to be noticeable.
(1) Both seller and buyer should cooperate on quarantine. When I order by mail, I clearly state this condition to the mail-order seller, requesting plant quarantine and purchasing only disease- and pest-free plants.
(2) After receiving the seedlings, carefully rinse the orchid plants with clean water, especially the dust inside the sheath leaves and the "V"-shaped angle at the leaf base, cut away any diseased leaf spots that were missed in inspection, then soak in a 0.3% potassium permanganate solution for 10 minutes, and rinse off the residual liquid with clean water to achieve the purpose of sterilization and disinfection.
(3) Potted plants that have already established must be observed carefully at all times; once found, isolate them immediately. For severe cases, cut and burn; for mild cases with a few small spots, apply a paste mixed from zineb powder or scorch them away with a heated iron wire. At the same time, from early summer onward, spray 600-fold zineb once every 15-20 days as a preventive measure (especially for varieties with weak resistance such as Cymbidium sinense and Cymbidium kanran).
(4) During the dog days, shade them during rainy spells lasting more than two days or heavy hot summer rain, and promptly withhold water, ventilate, and drain waterlogged areas; this is the period when disease is most likely to occur. (5) In spring and autumn, repot at the right time and replace with new soil; in daily care, regularly tidy up sanitation, remove sources of contamination, and regularly weed, intertill, and loosen the soil (without damaging the roots), to promote rapid evaporation of standing water and allow air and suitable light between soil aggregates; at the same time, topdress according to growth to restore vigor, and note the combined use of boiled soybean and sesame cake water with potassium dihydrogen phosphate.
(1) Both seller and buyer should cooperate on quarantine. When I order by mail, I clearly state this condition to the mail-order seller, requesting plant quarantine and purchasing only disease- and pest-free plants.
(2) After receiving the seedlings, carefully rinse the orchid plants with clean water, especially the dust inside the sheath leaves and the "V"-shaped angle at the leaf base, cut away any diseased leaf spots that were missed in inspection, then soak in a 0.3% potassium permanganate solution for 10 minutes, and rinse off the residual liquid with clean water to achieve the purpose of sterilization and disinfection.
(3) Potted plants that have already established must be observed carefully at all times; once found, isolate them immediately. For severe cases, cut and burn; for mild cases with a few small spots, apply a paste mixed from zineb powder or scorch them away with a heated iron wire. At the same time, from early summer onward, spray 600-fold zineb once every 15-20 days as a preventive measure (especially for varieties with weak resistance such as Cymbidium sinense and Cymbidium kanran).
(4) During the dog days, shade them during rainy spells lasting more than two days or heavy hot summer rain, and promptly withhold water, ventilate, and drain waterlogged areas; this is the period when disease is most likely to occur. (5) In spring and autumn, repot at the right time and replace with new soil; in daily care, regularly tidy up sanitation, remove sources of contamination, and regularly weed, intertill, and loosen the soil (without damaging the roots), to promote rapid evaporation of standing water and allow air and suitable light between soil aggregates; at the same time, topdress according to growth to restore vigor, and note the combined use of boiled soybean and sesame cake water with potassium dihydrogen phosphate.