Ferrante, senior pest control advisor for Teixeira Farms Inc. in Santa Maria, has conducted trials this year on Confirm, an insect growth regulator expected to be registered by Rohm and Haas Co. in a number of leafy vegetable and cole crops in time for the 1998 season. Comparing the IGR with standard sprays the grower uses to control fall armyworm, cabbage looper and other lepidoptera in his vegetables, Ferrante said he was very pleased with the results.

"I'm completely satisfied with using Confirm as a tank mix for lepidoptera," he said. "It's an exciting product if used properly in a good IPM program."

Confirm was first registered by Rohm and Haas in 1995 for the control of codling moth in walnuts, and the company is completing registration processes on a number of other crops, including apples and pears, tree nuts, forestry and vegetable crops.

Rohm and Haas for 1997 expects to have another experimental use permit for limited acreage in vegetables with full registration expected by the first quarter of 1998. Confirm is currently formulated as a 2F liquid flowable, but officials said the company plans to market Confirm in a 70-WSP water soluble pouch.

The active ingredient in Confirm, tebufenozide, works to selectively control lepidopteran pests by mimicking the ecdysone hormone naturally found in the worm pest that triggers the molting process in immature larvae. When larvae consume foliage treated with Confirm, the molting process initiates prematurely, the pest stops feeding and the worm ultimately starves, dehydrates and dies.

According to Ferrante, this mode of action requires some special considerations for PCAs. First because the insecticide must be ingested, coverage is extremely important, which means PCAs must use good application equipment and high water volume.

To ensure uniform coverage of leaf surfaces with a conventional ground sprayer, Teixeira Farms applied Confirm in 50 gallons of water. That rate worked will in all Teixeira trials, which included one 10-acre trial on cabbage and two 10-acre trials on head lettuce.

Teixeira Farms traditionally uses electrostatic sprayers on about 75 percent of its 4,000 acres of vegetable crops in the Santa Maria Valley, but went with conventional rigs on the 10-acre test plots to help Rohm and Haas gather conventional application data for the trial. With the use of an electrostatic sprayer, though, Ferrante said results could have been even better.

"I think it could be 30 to 40 percent better with electrostatic sprayers," he said.

The EUP label for Confirm 2F calls for rates of 4 to 8 ounces per acre, with minimum gallonage of 10 gallons by ground and 5 gallons by air, said Rohm and Haas Field Research and Development Representative Harvey Yoshida. But Yoshida said most trials have involved volumes of at least 30 gallons by ground, which appears to be providing adequate results.

In his field work throughout the Central Coast, Yoshida has had good success applying Confirm at the labeled rates of 6 ounces and 8 ounces in 50 gallons of water using conventional spray methods. Gallonage ranged in those trials from 30 gallons to as high as 75 gallons, with 50 providing a good median, he said.

"I was very satisfied with the way the application went on. And the results I saw just by looking at the counts were very encouraging."

Rohm and Haas Central Coast sales representative Tim Gallagher said the volume of water may be variable depending on the type and size of the crop. As crops get bigger, PCAs should consider increasing the water volume, he said. Rohm and Haas also recommends mixing Confirm with an adjuvant that has strong spreader/sticker properties in all applications.

In addition to coverage, Ferrante said timing is especially crucial to the successful use of Confirm. He targeted early life stages through regular scouting and then promptly sprayed at the first sight of eggs or feeding.

"The best time is on the early side, at first instar or second instar," Ferrante said. "On any worms, you want to get the worms when they're small, because if you wait until they're large, you're not going to get all of them."

Once the application is made, Ferrante noted, PCAs must then be willing to hold off and wait to see the results.

"You have to be patient," he said. "If you're doing a good job scouting the field and getting the worms as they hatch you're going to get quick results."

Because Ferrante is associated with the growing operation, he said he has the luxury of constant communication with the farm manager to help allay concerns from growers who are accustomed to seeing instant knockdown. But he realizes many independent PCAs working for service companies may not have that luxury

"A lot of times growers want to see results now," he acknowledged.

But if a PCA and his grower are willing to take the unique mode of action into account, educate himself and be patient, Ferrante said Confirm can be a valuable part of a resistance management plan and IPM program.

"It's a learning curve. But as part of a resistance management practice you almost have to make this part of the tool box. If you don't and don't educate yourself now, you're going to have some problems down the line," he said.

While Ferrante said he is experiencing only minimal resistance with conventional worm control products now on the market, he believes it's only a matter of time before cross resistance between currently available chemistry leads to lower efficacy with those products.

That's why he's looking to new products like Confirm to bring entirely different classes of chemistry into the rotation. Ferrante envisions Confirm fitting well into an IPM program once it is registered, particularly in the early and later parts of the crop season. Confirm has 14 to 21 days of residual activity and should protect the crop following the peak flight of each generation.

Ferrante expects to use Confirm as the second crop spray, after a knock-down application a couple weeks earlier for aphids or other pests in the field. An application 14 days or so later with Confirm could then get worm pests early on, without relying on broad-spectrum insecticides, which will allow populations of beneficial to develop in the filed and provide extra control of secondary pests. If needed, he could then look to a synthetic pyrethroid or other chemical, depending on the insect profile in the field.

Ideally, then, Ferrante said, a second application of Confirm might be made later in the crop cycle, as harvest approaches. Confirm is an ideal worm control product at the tail end of the season, when damage tolerance is minimal but as harvest dates approach, Ferrante said. Confirm's 7-day-to-harvest interval allows quick access soon after the application is made.

"My philosophy is the closer you get to harvest, the lower category products you want to use, " Ferrante said, adding that, "If you do a good job on the early side it will make it easier on the tail end."

While Rohm and Haas expects to fully label Confirm for a maximum of seven applications per season, Ferrante expects to combine a couple applications of Confirm without worm control measures to mix up chemistry in the field.

Imperial County Farm Advisor Eric Natwick said that resistance management applies to IGRs just as it does with other insecticide products. While IGRs don't seem to have a higher propensity toward resistance that other products, resistance has been documented in other growing regions around the world where IGRs are widely used and with very little regulation in terms of the number of applications and rates.

Yoshida said Rohm and Haas last year conducted field bioassays to determine baseline resistance or tolerances of beet armyworm to Confirm. Those trials should help generate baseline resistance levels for susceptible populations of beet armyworm to compare those levels with future generations after the product is more widely used.

"We're prepared to do some follow up work to see if we are starting to develop resistance," he said.

Natwick this year conducted a series of 18 small-plot trials on vegetable crops in Holtville, Calif., comparing Confirm with a barrage of other worm control products. While he was still finalizing data in late October, he said results appear to place Confirm well in the running with other classes of chemistry, including pyrethroids, carbamates, endosulfan, spinosyn and semi-synthetic avermectin, in terms of harvestable yields, quality and worm damage.

"At this point it looks like the Confirm will probably perform as well as standard treatments like Lannate or Phase/Asana or Phaser alone," he said.

In fact, one trial, which combined Confirm with Admire for whitefly control, may help improve yields in that plot because of the extra whitefly control of Admire - an important consideration in the Imperial Valley.

Worm counts were notably higher in the plots treated with Confirm, but Natwick said higher counts are likely due to the fact that worms don't die right away.

"In the case of Confirm, the worm counts look quite high, but the damage is not very high," he said. "It's a slow acting material. It takes five days for worms to die, although they do stop feeding right away," he said.

Although the treated worm is still living, it is no longer feeding; a new, malformed cuticle drops over its mouth once premature molting begins.

According to Yoshida, a lepidoptera that has fed on a leaf treated with Confirm will stop feeding within 12 hours of application. PCAs can also tell an insect has been successfully treated as it begins to get lethargic and in later stages may show some discoloration.

"What we've seen with the cabbage looper is the back portion of the larvae will be adhered to the plant surface," Yoshida said. "they're anchored down in the back."

Natwick said Confirm has distinct advantages and disadvantages over conventional sprays, but added that advantages appear to outweigh the drawbacks.

Its primary benefit, he said, is its safe environmental and worker safety profile and its beneficials- friendly nature.

"It's not going to kill any beneficial insects and it's not damaging to wildlife species, including birds, mammals and aquatic life."

According to the Rohm and Haas technical bulletin, Confirm is non-toxic to birds and honeybees and only moderately toxic to fish and aquatic invertebrates.

Confirm also seems to be compatible with most fungicides or insecticides that might be tank-mixed for other pest control needs, Yoshida said.

Confirm's primary disadvantage is its coverage sensitivity, but Natwick said that's something PCAs can learn to work around. He noted that there may be a dilution factor if Confirm is applied to growing plants, and eggs laid on new growth could feed on untreated foliage. Than's why regular scouting and application timing are so important.

"When you see worms out there, unless people are aware of the way material works, they could be very concerned about that," he said.

Still, he said, on the balance, COnfirm could be an important part of a slate of new worm control chemistries coming on line to provide growers and their PCAs more options.

That could become even more important with the recent passage of the Food Quality and Protection Act, which has many in the industry concerned about the future registration of pyrethroids and other broad spectrum products.

"There's a possibility we won't see new pyrethroid registrations for vegetable crops, and there's even a possibility some will be pulled." Natwick said. "We don't know until EPA interprets the legislation."

This is a chance though, that as manufacturers scramble to come in line with overall exposure tolerances, they may have to limit labels to high-value crops to lower those exposure levels.