HOW TO PROTECT YOUR ORCHIDS FROM THE RAINY SEASON

 

The rainy season is here and it’s a great relief that your plants will be spared from the hot scorching and drying sun, and the plants will now be freely watered everyday. However, too much rain can also have a disadvantage, as it can be a cause by rotting to your valued plants.

    Some of the common orchid genera  here in the Philippines includes the Cattleya, Dendrobium, Vanda, Oncidium, Phalaenopsis, and the Spathoglottis.  Each orchid has its own cultural requirement, and that is why each orchid has a different  cultural tip.  However, some of these tips can be generalized in a few simple procedures.

On the onset of the rainy season, orchid hobbyist spray once every two weeks  their plants with a dilute fungicide solution, usually Dithane, which is a synthetic  yellow powder mixed in water.  It is used as a preventive measure in order to avoid fungal diseases in establishing into your plants due to very high humidity.   However, for people who do not want synthetics,  the American Orchid Society recommends powdered cinnamon as an excellent fungicide.  Not only does it kill fungal pathogens, but it is also a safer alternative than synthetic chemicals around children and pets.

          Most orchids are particularly susceptible to black rot fungal diseases from Pythium and Phytophthora fungi. These pathogens cause leaves to turn black before they die. Diseases progress rapidly and can kill plants unless it is treated with a fungicide in their early stages.  Anthracnose (Glomerella and Colletotrichum spp.) one the other hand, moves from leaf tips to bases, turning leaves brown as the infection rots tissue. When Cercospora leaf spot infects plants, it causes chlorotic leaves, which turn yellow and bear dark spots that enlarge as the disease worsens.

                In addition to spraying fungicides, one has to clean and remove from your plants dried leaves, dried flowers, flower spikes, and dried leaf sheaths still clinging to the stem of the plant.  These dried plant parts becomes a haven for fungus and insects once it becomes wet and will start attacking your plants.

          If your orchid is infected with a fungus, you must first remove diseased parts before you apply fungicides. Apply ground cinnamon to exposed areas where you removed infected leaves, shoots or roots. You should also treat the surrounding tissue by first wetting dry areas so that the cinnamon adheres.  It is suggested that mixing cinnamon in oil or casein-based glue to make a thick paste before applying it over wounds and surrounding tissues. This holds the cinnamon next to the wounded surface and creates a waterproof barrier against pathogens.  That also goes true with commercial fungicides, and by mixing it with a few drops of water to make a fungicide paste.

            Fungicide application is not the only effective recommendation for having a disease-free orchid. In addition to this, practicing a scrupulous sanitation method when handling orchids, like washing and sterilizing pruning tools is a good way of preventing spreading diseases from plant to plant.  Also  providing  air circulation around plants, which can be done by spacing plants just sufficient enough so that mild of breeze of air can pass through them.  Another tip is to use potting media and containers with good drainage.  A clogged pot and an orchid soaked in water for days is a sure way of causing root rotting. 

          Check the potting medium for fungus or insect infestation.  Charcoal is the best potting media for aerial orchids here in the Philippines.  For added nutrients, one may place a thin layer of chopped coconut husk or chopped tree fern roots over the charcoal, or better still, add a few pellets of controlled orchid fertilizer.

           If there will be problems with insects, spraying with a recommended insecticide solution is recommended.   Regular fertilization of plants, at a frequency of once per week, using dilute orchid foliar fertilizer is another good way of making your plants healthy and be able to resist diseases.

If it is possible to move plants, move plants to an area protected from too much rain.  Or if it is possible to place a temporary plastic sheet roofing over your orchids, as in the case for Phalaenopsis and Dendrobiums, it is highly recommended.   However, for other orchids like Vandas and Cattleyas, they are best left there in the rain.

For more tips on orchid growing,  you might want to visit the Philippine Orchid Society’s  Midyear Orchid show which will be held on August 29 to- September 08,  2014 at the Quezon City Memorial Circle, Diliman, Quezon City.  The theme is  “The Great Orchid & Pet Expo” .  Aside from the orchid show, the event will also have a Pet Show on September 6 to 7, 2014.  The area will include an exhibit display, a trade fair and free lectures.