Overton, Texas
April 17, 2003
Writer: Robert Burns, (903)
834-6191, rd-burns@tamu.edu
Contact: Dr. Scott Ludwig, (903) 834-6191,
swludwig@ag.tamu.edu
A recent integrated pest management trial done with cooperation
from a Cherokee County plant farm demonstrated that Integrated
Pest management (IPM) methods can not only reduce pesticide
usage and still control insect pests, they can save greenhouse
managers money.
"Just when you think you know
everything there is to know, you realize there is something new
to learn," said Bobby Murray, owner of Murray Plant Farms near
Jacksonville, who recently worked with a Texas Cooperative
Extension IPM specialist.
Murray is no newcomer to the
nursery business. After leaving college, he followed in his
father's footsteps and purchased his first greenhouses in 1985.
Today, he operates 17 greenhouses, with 60 percent of his sales
consisting of hibiscus and the remainder in bougainvillea. Sales
include 5,000 12-inch pots of hibiscus, and 11,000 one-gallon
containers of both hibiscus plants and trees. He sells only
wholesale and mainly to independent plant stores in Dallas and
Fort Worth.
Specialization means Murray can
concentrate on doing what he does very well. But specialization
also means the outbreak of one plant disease or pest can be
devastating. Also, state laws used to require plants to be free
of all insects before shipping or sales. So even a small
infestation could result in a stop-sale order by the Texas
Department of Agriculture.
Consequently, when Murray began
his business he was spraying every two weeks. Later, his
practice evolved to spray as needed, though "as-needed" was
based on observation. If a few insects were found in one
greenhouse, it was procedure to spray all the greenhouses, just
to be on the safe side.
The "as-needed" program worked.
No crops were lost to insect infestation, but when Dr. Scott
Ludwig, Extension IPM specialist, advanced the idea that there
was a way to use less chemicals but still achieve good control,
Murray was interested.
"Using chemicals is not one of my
favorite things, so I was ready to try it," Murray said. Murray
was cautious, as are many plant farm operators. "There's a lot
of misunderstanding as to what IPM is all about," Ludwig said.
"First it's not about getting rid of all pesticides. Integrated
pest management is about the use of multiple techniques to
manage pest populations, of which pesticides are only one."
IPM is really based on common sense, Ludwig said.
"Pesticides are expensive, and it
really isn't cost effective to use them every time a couple of
insects are found. Also, although newer chemicals are much more
friendly to the environment, it's still not an
environmentally sound practice to apply pesticides without a
good reason. >From the standpoint of the bottomline, integrating
pesticide biological controls, cultural practices and other
means can save the producer money, labor and risk."
Murray and Ludwig began a
conservative IPM program in two of the plant farm's greenhouses.
No biological controls were tried. Instead of applying
pesticides at the first sign of insects, a regular scouting
program was initiated. Sticky cards – pieces of paper with a
glue base – were placed in the greenhouses. Insects are
attracted to the bright yellow color of the sticky cards. By
monitoring the number of insects found stuck to the cards,
Ludwig and Murray could draw conclusions on actual insect counts
in any given greenhouse. Ludwig also checks plants regularly to
estimate the actual levels of infestation. Murray only fogged
when the insect count reached numbers that could pose actual
damage to the plants.
Murray found the insect control
in the two IPM greenhouses to be better than those in his other
greenhouses. In one IPM greenhouse Murray fogged a total of six
times between Jan. 8 and Feb. 24. In the other greenhouse, he
fogged nine times. In comparison, Murray fogged his
conventionally managed greenhouses 15 times over the same time
period.
Murray saved an average of $50
per IPM greenhouse, a savings of 24 percent over conventional
methods. But there were other savings to which it's hard to
attach a dollar figure, according to Ludwig.
"There's the labor and human health issues involved in the six
to nine extra applications. There's also the lessened impact on
the environment.
" Moreover, using the same
methods, Ludwig believes it will be possible to increase the
savings next year through pre-season preparation. In subsequent
years, once he has a better idea of the pest populations, Ludwig
plans to supplement the chemical controls with biological
controls. Ludwig's work with Murray – and IPM in nursery
greenhouses in general – was made easier by a recent change in
TDA rules.
Old TDA rules dictated plants had
to be sprayed anytime any insect was found, and they didn't
discriminate between beneficial insects and damaging pests. With
the rule change, which came from collaboration among TDA
officials, Extension IPM specialists and commercial growers,
came a new official definition of a pest: "Any pathogen,
arthropod, or other non-vertebrae biological organism that is
detrimental to plants or plant products subject to regulation
under the Texas Agricultural Code."
The new definition meant
IPM-favored methods of using beneficial insects for control of
damaging insects could be used. Just as important, under new
rules a grower may file an IPM plan with TDA. With an IPM plan,
pesticides must only be applied when insect infestations reach a
predetermined level.
Greenhouse growers in East Texas
who wish to cooperate in an IPM demonstration or just learn more
about IPM can either contact Ludwig directly at (903) 834-6191
or call their local county Extension agent.
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