Have you ever considered growing your orchids using natural controls for disease and pests. There are a number of articles in orchid growing magazines suggesting various ways to use natural mechanisms in managing an orchid collection, but they are difficult to use and certainly not 100% effective.
Commercial greenhouses typically go the other direction, trying to
maintain as sterile a growing area as possible; no pests, weeds or
disease. Their goal is to produce perfect looking plants that can pass
any inspection when shipped. Most do a great job, but use many different
control measures that are not always the best for the environment or
people. They succeed largely because they only grow the orchids for a
relatively short period of time and then they start over with new
seedlings.
Those of us who maintain collections and plants, some of which may be a
100+ years old, do not have the luxury of starting out with pest or
disease-free plants every season. We get whatever comes with the plant
when we acquire these old clones and divisions. On the other hand, we
are not in business to grow plants quickly or to produce perfect looking
plants for sale to the public.
A few decades ago, farmers in the U.S. adopted a strategy of not using
pesticides or herbicides until the problem reached the point where not
treating cost more than letting the problem continue. As a result,
pesticide and herbicide use declined and farmers made more money; a
perfect win-win for farmers and the environment.
This has been my approach for many years. My greenhouse is home to
several dozen anole lizards (brown and green), Mediterranean geckos
(nothing like the GEICO one), hundreds of cricket frogs that are just a
½” in size, a few green tree frogs, 3 or 4 toads that frequent the damp
areas under the benches, and a snake or two (which may explain where one
of the toads went).
The fact that these predators seem to maintain a healthy population
suggests that they have plenty to eat. When I visit my greenhouse at
night, I find a few insects on the surface of the media, but not many.
My predators feed on any small insect they find during the day and
night. None of these predators impact cattleya scale at all, so I use a
hormonal pesticide (Distance) for control. This spray doesn’t seem to
impact any of my predators.
An orchid-growing friend asked me if I ever had problems with thrips. In
the past, there have been one or two incidents, but the thrips just
disappeared fairly quickly. I found some on a Camellia flower bud last
week and decided to try an experiment I hope I do not regret. I placed
the flower bud, thrips and all, in my greenhouse in a flower tube. When
I came back in 15 minutes or so one of the Carolina anoles (green ones)
was on the bud and not a thrip was to be found. The lizard looked happy
too.
The only other pest problems my natural predators seem unable to handle
are roaches (huge roaches, called palmetto bugs here in Florida) and
slugs. While toads will eat slugs, toads tend to stay on the ground,
while slugs love to get in the bottoms of pots. Both of these beasts
love to eat new roots and flowers. Looks like I need to find just one
more predator to add to my menagerie; one that is not afraid of palmetto
bugs and slugs that feeds at night. Any ideas?