Fresh From the Field - Agri-bytes, January 2010 - Fresh from the Field - Agri-Bytes

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Agri-Bytes
January 2010

In This Edition:

- Washington State University apple breeding program releases first cultivar, more to come

- Rotting produce could become a hot commodity as a fuel stock

- Control navel orangeworm to reduce aflotoxin in almonds

Washington State University apple breeding program releases first cultivar, more to come

By Vicky Boyd, Editor

Washington State University has released WA 2, the first of what it hopes will be a long line of apples from its pome fruit breeding program.

The variety, which matures in late September or early October, was released under a novel program that allows grower-evaluators to have first crack at future production expansion, says Kate Evans, pome fruit breeder at the university’s Tree Fruit and Extension Center in Wenatchee.

“It’s kind of a pre-commercialization release,” she says. “It’s kind of an open release within Washington state. It allows growers to get some trees and have a look at it. Then they can decide if they want to progress.”

But WA 2 will not be a club-type or managed variety, Evans says.

Whether the variety will eventually be available to growers outside of Washington has not been decided, she says, adding that Washington state growers provide considerable funding for the breeding program.

Evans says it’s too preliminary to assign a commercial name to WA 2.

“It’s really going to be up to whomever commercializes it to come up with a marketing name,” she says. “Obviously, the name will be a key part of that marketing program.”

Photo courtesy of Washington State University

WA 2 has outstanding fresh-market qualities, including balanced flavor, firm fruit and excellent storability.

WA 2 is the first release from the university’s apple breeding program, which was started in 1994. Bruce Babbitt, the apple breeder who retired in 2008, was instrumental in developing it, Evans says. More varieties are in the works.

WA 2 has outstanding eating quality and matures in early fall. Between 70 percent and 90 percent of the skin surface is covered with an appealing orange-red to pinkish-red blush over a yellow background. Large, conspicuous lenticels help distinguish it from other cultivars.

The fruit are round and typically medium to large in size—larger than Gala but smaller than Fuji. In other words, WA 2 fruit size is comparable with Braeburn.

Sensory panels have rated the variety high, with a balanced flavor.

Sugar content is similar to Fuji and Pink Lady, but acid content is more in line with Jonagold, Honeycrisp and golden delicious. WA 2 contains the low-ethylene gene, so it is very firm out of storage.

Evans says she doesn’t know if there are any rootstock incompatibility problems since it has only been grown on M9.

Based on the limited experience with the cultivar, it doesn’t appear to be super susceptible to fire blight, she says.

For more information on how to become a P4 apple variety evaluator, visit www.tfrec.wsu.edu/pages/wa2/Participate. Sign-up runs through March 31.

Rotting produce could become a hot commodity as a fuel stock

By Vicky Boyd, Editor

One man's trash is another man’s treasure—or in this case, fuel stock.

University of Georgia researcher Gary Hawkins is working on a process that would convert rotten fruit and vegetables into methane gas, which can be burned to heat greenhouses, produce driers, shops or houses.

“If we can get the process down, packers and producers should be able to make money off of it,” Hawkins, a pollution prevention and alternative energy specialist with the UGA College of Agricultural and Environmental Sciences, said in a new release.

Of the 390 million pounds of produce that Georgia growers harvested in 2007, 8 percent—or 31.2 million pounds—were culled by packinghouses. And that’s just one state and doesn’t count the produce left in the field unharvested each season.

Not all produce is created equal when it comes to methane-producing potential, either. On the vegetable side, onions have the greatest potential to produce the most methane. Tomatoes were a disappointment, he says.

On the fruit side, blueberries are the winners.

Hawkins uses a process called anaerobic digestion, which harnesses bacteria that can live without oxygen to break down the fruits and vegetables. In the process, they emit methane.

But too much produce can be harmful to the beneficial microbes.

“We will kill it if we put too much in there,” he said. “A pH below 4.5 kills the system. The bacteria get obese, overeat and kill themselves.”

Anaerobic digesters also have to be fed a steady stream of produce or the bacteria will die. In addition, changing the amount or kind of material fed to the digesters too quickly can be lethal to the bacteria.

“If a digester goes bad, it smells real bad,” he says.

Well-run digesters, on the other hand, produce an odor, but Hawkins says it’s much better than the smell of produce rotting in the field.

Control navel orangeworm to reduce aflotoxin in almonds

By Vicky Boyd, Editor

If you control navel orangeworm in almonds, you can significantly reduce your incidence of aflotoxin, a naturally occurring cancer-causing substance produced by the fungi Aspergillus flavus and A. parasiticus.

That means applying timely in-season hull-split sprays, harvesting early if possible and performing winter orchard sanitation to remove mummies where NOW can overwinter.

That was the message delivered by plant pathologist Themis Michailides and microbiologist Jeff Palumbo at the recent Almond Industry Conference in Modesto, Calif.

Not only does aflotoxin pose a danger to animal health, but high levels also can cause European buyers to reject loads. A single rejected load could cost the shipper as much as $10,000 in warehousing, replacement shipments and other expenses. Under the worst case, the shipment could be destroyed.

Beginning in 2007, the European Union required that at least 5 percent of all loads of California almonds be tested for aflotoxin after they’ve been tested under a voluntary program conducted in California. Loads that haven’t undergone the voluntary testing are subject to 100 percent testing.

The EU represents 55 percent of almond export shipments.

A. flavus and A. parasiticus occur naturally in the state’s soils, says Michailides, a University of California plant pathologist stationed at the Kearney Agricultural Center in Parlier. The nut crops—walnuts, pistachios and almonds—are not nearly as frequently contaminated with aflotoxin as cotton, corn or even peanuts, he says. Nevertheless, the organisms and their byproducts remain a big concern for the industry.

Michailides collected soil samples from 28 almond orchards—11 in the north, nine in the central park and eight in the south. He grew the organisms out on Petri dishes to aid in identification.

“All of the orchards had some levels of these fungi,” he says, adding that all of the levels were low.

He then collected almond mummies from 21 orchards and examined the contents. Between 60 percent and 90 percent of the mummies were infected with A. flavus, he says. And up to 42 percent of the NOW larvae in the mummies were contaminated with aflotoxin spores.

About half of the adult moths that emerge from those mummies carry aflotoxin, which makes the first generation the most troublesome, he says.

NOW appears to have the unique ability to survive aflotoxin concentrations that are 100 times higher than doses lethal to other organisms, says Jeff Palumbo, a research microbiologist with the Agricultural Research Service in Albany, Calif.

Palumbo examined 50 26-pound lots of almonds for insect, mechanical and mold damage. Of the 7 percent insect damage he identified, 76 percent of those damaged nuts carried aflotoxin.

“Insect control and orchard sanitation are the key to reducing aflotoxin,” he says, adding that good agricultural practices are the first step.

Growers also should perform winter sanitation to remove mummy nuts by March 15. The UC Cooperative Extension recommends a goal of no more than two mummies per tree.

During the season, Palumbo encourages growers to monitor NOW flights and apply timely insecticidal sprays to prevent egg-laying during hull split.

If they can, growers should harvest early and pick up nuts to reduce exposure to the third NOW flight, Palumbo says.

For more information about aflotoxin prevention in almonds, visit www.almondboard.com.