A new seed technology being tested in Weslaco could mean the end of early insecticide sprays on some vegetables. It's called "film coating," a process which treats seeds with insecticides and other materials to manage insects.

"Film coated seeds are still being tested here and elsewhere, but results so far look very promising," said Dr. T-X Liu, an integrated pest management entomologist at the Texas A&M Agricultural University System Research and Extension Center at Weslaco.

Liu has planted treated seeds of various fall crops and is monitoring them weekly for insect damage. The infant plants are already showing insect resistance compared to a control plot of plants from untreated seeds.

"It is far too early to make any definitive determinations," he said, "but in our first weekly evaluation, we saw that the treated plants didn't have the leaf damage from cabbage loopers and diamondback moths that we saw in the untreated plants."

The seed treatment process was borrowed from the food and pharmaceutical industries, and developed for agricultural applications by Cornell University professor Dr. Alan Taylor at the New York State Agricultural Experiment Station.

Taylor's lab is one of few university facilities in the country set up to treat seed with coatings of systemic insecticides that protect a plant from soil-borne and leaf-chewing insects.

Taylor said seed coating promises huge environmental and financial advantages for specialty, or minor-use crops such as vegetables.

"Seed coating means growers can use very small amounts of insecticides per acre," Taylor said. "The systemic aspect of the insecticides on the seeds gives protection from insects for about 30 days, meaning that growers can avoid the costs and labor of foliar insecticide sprays, as well as having to physically handle those insecticides."
Longer-term vegetable crops, such as onions, would require conventional insecticide sprays to control insects after 30 days, Taylor said.

Specific seed treatments for sweet corn and onions were approved by the Environmental Protection Agency about 10 years ago and another for snap beans about three years ago. But research continues for the use of newly developed insecticides on seeds, including the onion seeds Liu is testing.

As part of a U. S. Department of Agriculture IR-4 project, Liu is testing seed-treated onions for resistance to onion maggots and onion thrips.

He will also evaluate seed-treated carrots for resistance to carrot weevil, radish for resistance to root aphids, and cabbage for resistance to a host of pests, including aphids, whiteflies, thrips and worms.

"We planted the cabbage and turnip plots first, then the onions and carrots," Liu said. "By November, we should have results from the carrots and cabbage, but we won't have results on the onions and radish until next year."
The process of treating seeds was years in the making, Liu said. Early failures included short-lived insecticidal effects and protection to only parts of the plant.

"Insecticides are now slowly released throughout the plant for up to about 30 days," he said. "We still have a lot of evaluations to make, but if this process is successful, imagine the money, labor and time our growers could save by planting pre-treated seeds, as well as the benefits to the environment."

Taylor said the major focus of his research now is to improve the controlled release of seed treatment and to better understand the movement of systemic insecticides throughout the plant.

"Many vegetables are transplanted from a greenhouse to the field, so we'd like to delay the release of insecticides until the plant is out in the field," he said. "And we'd like to better understand how the insecticide is diffused in the plant in order to better manipulate how fast or slow the insecticide is released. It's those early stages of seed treatment that we don't yet understand."