Orchidology: for serious collectors
Orchid cells have been to the International Space Station.
Wagner Vandrame, associate professor of Environmental Horticulture with the University of Florida’s Tropical Research and Education Center in Homestead, sent orchid tissue to the Space Station in 2007, and found that without gravity they do indeed grow faster than in our backyards. The experiment is part of a larger effort aimed at finding the best way to grow and conserve orchids threatened in the wild.
Vandrame hosted an “Orchidology” course Friday at Fairchild’s 9th Annual International Orchid Festival. He gave an overview of orchid history, from ancient Greece to the present, then followed that later in the afternoon with a look at orchid flowers “up close and personal” to dissect their petals and parts.
For serious orchid growers, it was a one-day crash course.
Catharine Mannion, entomologist with UF’s Institute of Food and Agricultural Science in Homestead, brought her expertise to the course by explaining how to recognize the damage done by chewing insects versus piercing-sucking insects (scales, thrips, mealybugs and mites). She concentrated, too, on the predators of these insects, so that good bugs aren't blitzed with the bad.
The piercing-sucking insects insert a straw-like mouth-part into orchid tissue and drink, causing yellowing, browning, and eventual decline of the plants. Scales, mealybugs, thrips and mites are the culprits, often found on the undersides of leaves or in leaf axils.
Thrips have both a sucking mouth-part as well as a mandible, meaning they can suck juices as well as chew orchids. Their preferred target: flowers and flower buds.
Mannion also looked at aphids, mites, blossom midges, and the damage done by caterpillars and snails. She urged everyone to recognize the good insects, and to use care when selecting chemicals. Soaps and oils to combat bad insects may cause damage to orchid plants in heat, so caution is needed with these products, too.
Fungal disease is the most common of all plant diseases, said Aaron Palmateer, UF pathologist. Orchid fungal diseases include black rot, which commonly occurs in over- watered cattleyas; anthracnose, which produces dead areas of leaves that have bands or striations in them and fusarium wilt, which infects the roots and lower stems or orchids. Phyllostrictina leaf spot, or Thai fungus, crops up when orchids are stressed by cold or high temperature extremes, and produces narrow streaks that can coalesce into large lesions.
Bacterial diseases cause oozing areas on orchid leaves, often accompanied by a bad smell.
Virus diseases have various symptoms, including black streaks, purple spots and swirling patterns. They cause “color breaks” in flowers, so that uneven color streaks and splotches may occur. Spread by insects, such as aphids, viruses often are fatal. Virus-infected plants are best discarded to avoid the spread of infection
For more help, Palmateer and Mannion have invaluable websites. Palmateer recommends www.plantclinic.org; Mannion recommended http://creatures.ifas.ufl.edu, among others, plus her personal website: http:// trec.ifas.uf.edu/mannion.
For the orchids lovers intent on learning everything about caring for their beloved plants, the course was invaluable.