Integrated Pest Management in greenhouse means cost savings, less environmental impact

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.

TAMU news release
5665

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