But colored peppers also carry risks, so weigh both sides carefully
By Marni Katz
Colored bell peppers may bring a premium over their mature green counterparts, but they also carry additional risks and require added inputs.
Careful pest scouting, an integrated pest-control program and even growing under contract can reduce many of the threats, experts say.
And educating buyers about the challenges posed by the crop also may help, says Tony Bratsch, a former Extension horticulture specialist with Virginia Tech University in Blacksburg.
Most buyers want peppers with 100 percent surface color and are accustomed to greenhouse-grown varieties from Holland that are grown in a protected environment, he says. The result is thick-walled fruit.
“Field-grown and greenhouse-grown systems are very different, and the buyers should recognize the challenges of open-field production,” Bratsch says. “A field-grown pepper picked at 70 to 80 percent surface color change has a longer transit time and shelf life, and [this] allows the grower to successfully harvest more fruit versus fruit picked at 100 percent color change.
“The buyer needs to be happy with a pepper in color transition, which will eventually develop full color off the vine and in the marketing process.”
Peppers are vulnerable to the slightest injury during the two weeks from the time the fruit reaches mature green to the time it turns purple, chocolate, red, orange or yellow, Bratsch says.
“Once the pepper begins to turn full color, its resistance to damage and ability to heal surface wounds is minimal,” he says.
Any damage to the surface of the fruit from bacteria, insects, sunburn or physical injury causes the fruit to drop quickly.
Growers who push their mature peppers to full color typically can expect to lose at least 30 percent of their crop. The exact amount of the loss largely depends on how well growers manage the crop late in the season to protect softening fruit from injury.
A three-year effort
Bratsch began work in 2002 on a three-year project to develop a best-management system for colored peppers. The study initially focused on strategies that would reduce the crop losses growers often sustain after bell peppers reach full maturity.
“Bell peppers, once they reach full maturity and start to color, are basically a senescing fruit,” he says. “So the question is, how do you manage a senescing fruit and keep it on the vine a little longer for maximum color change?”
Therefore, Bratsch says it is important to select varieties that will change color more quickly.
"What we are looking at is the length of time they are on the plant after full maturity,” he says. “That is very critical. You need a shorter-season pepper, not necessarily the one that is the largest or best pepper. Look at the shorter-day variety because those tend to color a lot faster.”
Corn pest attacks peppers
Ultimately, Bratsch and fellow researchers concluded that most of the pepper damage and accompanying losses were caused by European corn borers.
After two years, the project shifted focus to look at using commercially produced, parasitic Trichogramma wasps to control corn borers in colored bell peppers.
The researchers found that Trichogramma releases controlled corner borer as effectively and economically as conventional insecticidal treatments, such as oranophosphates, synthetic pyrethroids, spinosad and other materials.
Thousands of the tiny parasites were released seven to eight times throughout the season from capsules tied to plants.
“When we did nothing to control insects in our trials, we were losing 70 to 80 percent of the fruit, and with a standard insect control program we lost 35 to 50 percent,” he says.
To be successful with colored pepper production in Virginia requires a regular spray program to keep insects out and diseases in check, Bratsch says. Growers also should try to minimize fruit injury during string trellising, harvest and packing.
Prevent sunburn to cut fruit loss
The exact cause of loss depends on production practices and climate within a field and varies from one part of the country to another.
In California’s Central Valley, University of California Cooperative Extension Farm Advisor Brenna Jane Aegerter says worms and stinkbugs typically are the greatest pest issues. They can grow incrementally worse as the season progresses, just as peppers are turning color. Abiotic disorders, such as spot, also can increase as fruit colors.
“Not all fields have it, but more and more spot is going to show up as the crop matures,” Aegerter says. “So there will be increased losses as we try to get the fruit to color.”
But sunburn probably is the biggest nemesis for late-season colored peppers in California.
“In order to prevent sunburn, you’ve got to maintain a good foliage cover over the fruit,” she says. “Anything can cause a loss in foliage, whether it’s irrigation management or disease.”
Yellow varieties tend to be more sensitive to sunburn than red varieties,” Bratsch says. Staying on top of fertility and irrigation is the best strategy to ensure good plant health, build a vigorous canopy and reduce defoliation.
Building a better pepper plant
San Joaquin County, Calif., pepper grower Larry Togninali says he regularly applies potash and specialty fertilizers through his drip irrigation to help thicken fruit walls, making the fruit tougher and better for roasting.
The drip also allows him to better manage his irrigation water and build a strong plant canopy, which prevents fruit sunburn.
“The main key when you establish the plants at transplanting is to get them to grow without growing too much,” Togninali says “You’ve got to try and set your plant first before you set your crop. It takes some practice to build the plant first, and you can only do that on drip, not on flood irrigation.”
The downside to the large canopy is that pesticide coverage can be more difficult.
“So you just build yourself a good spray rig and rely on ground applications instead of aerial applications and take care to do it well,” he says.
Contracts help reduce risks
In the mid-1980s, Togninali grew hundreds of acres of peppers in Stanislaus County until mosaic virus wiped out the fields. He now grows a few dozen acres of the Baron variety under contract.
Initially, he picks the fruit for the green market and then lets the remainder of the crop turn red.
“We will start picking around Aug. 15 and will go into mid-October,” Togninali says. “I’m on drip, so my plants keep going. I usually get rained out before I finish a field.”
He says growing colored peppers is a huge investment, but he manages the risk by growing only under contract.
“With red bells on drip, when I’m done picking, I’m in for over $6,500 an acre," Togninali says. “On drip, I can’t go out and sell peppers for $5 a box, so I’m better off with a guaranteed contract price. All I need to worry about is volume. I don’t even order the seed until I have a contract in hand.”