February in Wheatifield isn't really tomato season -- except for those 12 acres off Shawnee Road.

It's about 15 degrees under slate-gray skies, but inside the Fortistar greenhouse, it's a balmy 70 degrees. The heat comes from a power plant two miles away, used after it turns electricity-generating turbines.

That's one of a score of high-tech and bioengineering innovations that allowed the greenhouse to produce about 2 million pounds of tomatoes here last year. Most of the "baby Roma" and cherry tomatoes were sold by the plastic clamshell in Wegmans stores, but Fortistar tomatoes have been enjoyed from Indianapolis to New Jersey.

These tomatoes are essentially handgrown, plucked from vines groomed meticulously by greenhouse workers -- mostly Burmese immigrants, along with Africans, Thais, Americans and Jamaicans -- who do the painstaking handwork of tomato vine husbandry.

Baby Roma tomatoes grow best as a cluster of eight flowers, so a worker will count eight blossoms and pinch off the rest. "That way you get the perfect weight, every tomato looks the same," said Fortistar head grower Jason Gould. "Everything in a greenhouse is uniformity."

The plants are fed a computer-adjusted nutrient diet through a hydroponic drip system. But all that technology wouldn't work without a healthy dose of nature under the glass. Few who have enjoyed the flavor of Fortistar's local tomatoes in February have any inkling of the tiny, vicious wars fought to make that cherry tomato possible.

There's one clue on the tomato packages, which say they're grown with "integrated pest management." That is a boring way of saying, "We send bugs to assassinate the bugs that are bothering our tomatoes."

In this greenhouse, insect workers are as necessary as the humans. It starts with pollination, the crucial process of transferring pollen grains between open flowers to start the fruit-growing phase. "When you're growing outside, a tomato plant will pollinate itself by wind," said Gould. "When you're inside, in a closed environment, we don't want wind on the crops."

That's why there are bumblebees sailing around the neat green rows of plants, scampering from blossom to blossom, feasting on the pollen bonanza and taking lunch back to a shoebox-sized cardboard hive.

"You can check if the bees are doing their job, because they make little brown marks where they grab the flower with their mouths," Gould said. "You can see the marks where the bee has been there. If you don't see enough brown marks, you need more bees." Hives are added about every six to eight weeks, he said.

Honeybees have been tested for similar work, but they are light-sensitive, and in February the greenhouse might get only six hours of sunlight. "Bumblebees will work in the light, in the dark, it doesn't matter," said Gould.

"They're the hardest workers out there," joked Dan Sztorc, Fortistar's assistant general manager.

But Gould's insect-wrangling mission also includes playing defense. Invisible to all but the keenest watchers are tiny wasps called Encarsia formosa, which seek and destroy the eggs of whitefly legions that would suck the life from the tomatoes.

"These are the encarsia cards," said Gould, holding a business-sized card in the palm of his hand. Millimeter-sized black specks are stuck to a small circle. "These are actually whitefly eggs that have already been parasitized with encarsia. They hatch and fly around and find whitefly eggs that are in the crop."

The wasp cards, which Fortistar orders from a Belgian company, get hung up whenever the wasp population seems to be thinning.

There's a whole crew of whitefly killers that Gould can summon into battle: a long, slim fly called dicyphus attacks whiteflies, too.

The dicyphus used to arrive by mail, like the wasps. But "they worked too good," and repopulated themselves ably, so the insect companies stopped selling them.

That's why Gould and his crew got into the insect-growing business. Inside an aquarium in one of the greenhouses, dicyphus rest on fat, pale-green leaves of host plants, sunning under heat lamps.

"At the end of the season, before we clean up, we go through with a little jar and a tube and we suck them up, to save them," said Mike Goerss, assistant grower. The light-sensitive bugs won't reproduce without lights, so they're kept in the chamber. "Come March or April we'll let them go in the crop again," he said.

They get meals, too. "They eat a cereal aphid that comes freeze-dried," said Goerss.

Another tiny but bloodthirsty bug called the Swirski mite hunts the tomato-killers called thrips. There's a bug called colamani that's also peckish for aphids. All told, there are five insect species defending the tomatoes.

Then there's the plant allies. The growers have planted rows of eggplant to attract aphids away from the tomatoes. The aphids prefer the eggplant leaves, and they don't hurt the eggplant crop.

Fortistar can't market its tomatoes as organic, because its fertilizers aren't organic, Gould said. But the combined effects of the insects and other measures have allowed the company to avoid using any pesticides inside the greenhouses for the last three seasons, he said.

The switch to integrated pest management was done about four years ago, Sztorc said. "We were spending $50,000 a year on pesticides. Now we spend next to nothing."

As the insects do their jobs, the human workers move along the rows in electric carts. They train tomato vines up a string that hangs from a ceiling-mounted spool.

A single tomato vine can grow to 40 feet by the end of a nine-month season, but it's manipulated to only grow tomatoes at the end. As it grows, workers will pluck off branches and suckers, leaving 15 branches per plant.

Meanwhile, water and nutrients flow from the hydroponic drip tubes into the shredded coconut husks filling the tomato plants' root bags. Excess water is treated and recycled, and every two weeks it's tested to determine if the tomatoes' menu should change, to make a healthier plant and a tastier tomato.

Fortistar has grown cantaloupe and cucumbers in the greenhouse, but nothing has been as consistently rewarding as tomatoes.

"With hydroponics you can change the menu," said plant manager Gary Gust. "With soil, you get what you get."