On a cold, but not bitterly cold, overcast morning in late February, a light dusting of snow on surrounding hills serves as the only sure indicator that winter still holds sway in the Rogue Valley.
The valley’s commercial pear orchards produce famed fruit. But, at first glance, the trees appear locked in the stillness of dormancy that enables survival through a season of cold. A closer look at some of the pear trees reveals that all is not still.
Rick Hilton, an Oregon State University faculty research assistant, who works with area growers, walks an interested visitor around the grounds of Oregon State University’s Southern Oregon Research and Extension Center (SOREC). Close up, the pear trees are alive: new buds are pushing forth. Soon, pinkish-white blossoms promise that fruit will once again hang in abundance.
Hilton, an entomologist, has his work cut out for him. Growers here do battle every year with the codling moth, a key insect pest of pears. Hilton is investigating new pest-control techniques growers may one day use to achieve nearly total control of codling moth without relying on highly toxic chemical sprays.
For a pear to sell, the exterior of the fruit must be near blemish-free. And, if you want repeat business, no worm should greet the eater in the pear’s interior. "It has to be a picture-perfect piece of fruit," Hilton said.
Oregon pear growers last year produced about 219,000 tons of fruit on more than 17,800 bearing acres. Though the price many farmers received for their crop took a sharp drop in 2000 (see sidebar), pears were still worth more than $62 million to growers and contributed many more millions to Oregon’s economy.
European pears are Oregon’s most important commercial tree-fruit crop, and the state contains two of the world’s great pear-growing regions — the Rogue Valley in the south and the Hood River Valley in the north.
Building and maintaining an agricultural enterprise of this importance doesn’t come without a lot of work from growers and other members of the state’s pear industry.
For decades OSU scientists have worked in partnership with growers, packers and other industry players. Four OSU researchers at the Mid-Columbia Agricultural Research and Extension Center (MCAREC) in Hood River cooperate with two OSU researchers in southern Oregon at the SOREC station near Medford. These researchers cooperate in identifying pest insects and plant diseases, developing more efficient methods of pest control, and providing a broad variety of research and Extension educational information to pear growers in both growing regions.
This total research effort makes Oregon a leading center for pear research, said David Sugar, who guides post-harvest disease control studies at SOREC. One of Sugar’s primary research interests is finding new and more efficient technologies for the control of post-harvest diseases in pears, including several types of fungal rot.
"The economic loss from pears rotting in storage is one of the biggest problem areas in which growers ask for help," said Sugar. In 1984, he initiated a pathology program at SOREC to study the problem.
"We’re seeking the best way to maintain quality during long-term storage and to extend the marketing period," Sugar said.
In Hood River, Clark Seavert, superintendent of the MCAREC, said Hood River growers share problems with Rogue growers because of the nature of the pear crop.
"Our main focus has been on production, and that will continue," Seavert said. "You have to produce a good quality product and present it to the packing house, preferably large-sized fruit with no insect or disease problems, and be able to store the product for the length of the marketing period, so that when you take it out of storage and present it to the consumer, it’s a very good-looking piece of quality fruit."
To do this successfully, growers have to combat a variety of plant diseases and insect pests, so OSU researchers at the two research and extension centers find common ground in these areas. In other cases, problems are specific to a region.
For example, in Hood River growers tend hundreds of acres of Anjou orchards. Anjou, a thin-skinned yellowish, green or red pear, is the dominant variety grown in Hood River. Recently, some of the red Anjou trees there have been attacked by a mysterious ailment that causes leaves to collapse and roots to die. However, red Anjou failure, as Hood River researchers are calling it, has not turned up in southern Oregon pear orchards.
Red Anjou failure "is unique to Hood River, so we have (MCAREC researcher) Gene Mielke working on it," Seavert said.
In southern Oregon, Rogue Valley orchardists produce all types of pears on about 6,500 acres. Area orchards bask in the hot summer days and roots thrive in the region’s heavy clay soils, producing some of the world’s best Bosc and Comice pears. These two varieties dominate Rogue Valley production.
The remainder of the commercial acreage is in the Hood River Valley, east of Portland in the Columbia River Gorge. Hood River orchards are planted in volcanic soils and experience a cooler summer that’s also ideal for pears.
All pears are picked by hand and carefully placed into special orchard bins to prevent bruising. A pome fruit, pears are related to the apple. Pears can be eaten fresh, canned or baked. European pears grown in Oregon include Bartlett, a summer pear, and Anjou, the most abundant fresh winter pear. Other varieties include Bosc, Comice, and the tiny Seckel.
Pear harvest in Oregon begins with Bartletts in early August. Winter varieties are picked from August through October. Pears are harvested when fully mature, but not yet ripe. If allowed to ripen on the tree, pears will lose much of their flavor, and their soft flesh will become "gritty" with deposits of lignin and other organic compounds.
Laura Naumes helps guide Naumes Inc., a Medford-area fruit grower/packer. Her family was in the fruit business when she met and married Mike Naumes, whose father started Naumes Inc.
With about 2,000 acres of tree-fruit orchards in the Rogue Valley, Naumes is the area’s largest fruit grower. Most of that acreage is in pears. The company packs and sells fresh pears. It also operates three fruit-juice concentrate plants, one in California and two in Washington.
"Pears are difficult to work with," Laura Naumes said. "We harvest them as a nonripe product. Then the product has to be ripened properly. They’re a delicate fruit that bruises easily. They’re more difficult than apples to handle properly."
Naumes Inc. has been working with OSU researchers for at least 20 years, Laura Naumes said. OSU researchers are well known within the pear industry for their work on disease control, harvesting methods, storage issues and pest control.
"They cover the whole gamut in the industry, trying to improve the product," Laura Naumes said. "They have a good rapport with growers here, helping growers apply that research. They’re very open about helping growers in this area."
The research focus at SOREC has changed over the years, David Sugar said. Formerly known as the Southern Oregon Experiment Station, SOREC has been in existence since 1911, and at its current location just outside of Central Point since 1958. Times change, and so do the problems growers face. In the early years, the focus was on horticulture and improving growing practices. As more and more growers adopted these practices, pear yields increased, with the result that more pears were stored for longer periods of time before being marketed.
Today, post-harvest control of fungal rot in storages is one of two principal research areas at SOREC. The other is helping growers deal with insect pest problems using integrated pest-control techniques. That effort is led by entomologist Rick Hilton.
Once harvested, mature pears have to be chilled before they will ripen properly. Pear varieties differ in the amount of cooling needed. Bartlett pears only need from one day to two weeks. With winter pears, such as Anjou, Bosc and Comice, the cooling must go on from two weeks to six weeks. For long-term storage, pears are held at 30 degrees to 31 degrees F.
Once off the tree, pears continue to breathe, taking in oxygen and releasing carbon dioxide. Experience has shown that many fruits store longer if they are kept in an atmosphere of reduced oxygen as compared to the oxygen concentration of the air we breathe. Some packers rely on sealed rooms that use pumps and electricity to create and maintain a low-oxygen environment, a technique called controlled atmosphere (CA) storage. "Growers who don’t have CA know they’re going to lose quality," said Sugar.
Sugar is testing to determine if pear packers can rely on modified atmosphere packaging (MAP) to provide a low-cost storage option as well as create an environment that can extend fruit storage life. MAP technology makes it possible to extend the life of packaged foods through the modification of gases surrounding the food inside the wrapper.
Sugar is testing a type of MAP, a plastic bag designed and developed by an Australian firm, to see if the bag can provide CA conditions without the need to build a CA room. Pears are placed in the bag, which is designed to allow for the passive infiltration of oxygen at a rate that keeps pace with pear respiration, so that oxygen levels inside the bag don’t dip to damaging levels.
Sugar is also exploring the role played by carbon dioxide in long-term MAP storage. "Evidence suggests that elevated carbon dioxide suppresses fungal diseases and promotes retention of green color in fresh green pears. It’s all about maintaining quality over time and doing it without the large capital investment [needed to build more contolled atmosphere rooms]."
Another aspect of Sugar’s research is assisting other OSU researchers in building a multi-pronged approach to controlling fungal decay in long-term storages. Sugar and OSU researcher Tim Righetti have shown that managing levels of nitrogen and calcium in pear trees can work to enhance resistance to postharvest decay.
Sugar also contributed to a successful research effort lead by Bob Spotts, a MCAREC plant pathologist in Hood River. Together, the two showed that a biological control agent, in this case a yeast, can be applied to the pears after harvest, and the yeast will work to inhibit the growth of rot fungi.
The integrated approach OSU researchers take with pest control can lead to some happy coincidences, Sugar said. For instance, SOREC’s Rick Hilton was studying the use of a kaolin clay product for the suppression of insect pests. A chance observation found that if the clay is applied at the proper time, it will suppress insect pests as well as the development of russet, or light-brown blotches, on the skin of certain pear varieties. The presence or absence of russet on pears is an important marketing quality for certain pear varieties, Sugar said.
Large-scale studies during the last two years in area orchards confirm that kaolin is effective in russet suppression in Comice pears, the variety most used in Christmas gift packs produced in Medford, Sugar said.
Entomologist Hilton is leading the other major research initiative at SOREC—integrated pest management (IPM). He is working to move growers away from the highly toxic, broad-spectrum sprays and towards more environmentally sound and possibly less expensive pest-control techniques that rely on mating disruption for control of codling moth, the No. 1 insect pest of pears.
Rogue pear growers, trying to cope with increased environmental regulations regarding pesticides, have recently put several thousand acres of pears under mating-disruption programs, a key element in an overall IPM effort in pears. Hilton is assisting growers in monitoring these orchards.
He will be working with orchardists again this year to test new dispensing systems for the mating-disruption pheromone, in the hopes of finding one that is equally effective but less expensive than the current dispensing method.
A pheromone is a chemical secreted by a living organism that influences the behavior or development of others of the same species. In the case of the codling moth, the female releases a sex pheromone designed to attract a male for purposes of mating. Mating-disruption programs aim to confuse the male by the release of a high concentration of female sex pheromone into the orchard environment. This excess pheromone makes it difficult for males to locate females.
One new dispensing method is a pheromone-filled aerosol can that lets out a burst of spray every 15 minutes. Another is a micro-encapsulated pheromone formulation that can be applied with a spray rig.
"We know that mating-disruption can work, and we’ve shown that mating-disruption is almost always cheaper than conventional broad-spectrum spray pesticide programs," said Hilton. "We’re testing which (dispensing) method works best, and which is most reliable" in preventing codling moths from laying viable eggs.
As part of a total IPM program, Rogue orchardists also use low-toxicity pest sprays. While these sprays are easier for growers to apply because they don’t have as many regulations attached to their use, no one knows the impact the sprays have on beneficial insects such as lady beetles, lacewings and earwigs, which live in valley orchards.
"We’re improving the pheromone-based system and making it more reliable and stable," Hilton said. "Growers hate surprises, and we’re trying to take the element of surprise out of the mating-disruption system."
He’s also exploring how cover crops in the orchard affect insect populations. Cover crops, such as clover or winter rye, are planted in orchards to protect the soil from the action of rain during the winter and to provide humus and nitrogen to the soil when plowed under in spring. Cover crops planted to grow along with the tree crop also attract a variety of both good and bad insects to the orchard. Hilton is experimenting with different cover crops to see if some are better than others at bringing in beneficial insects.
"The question is, how do you weigh the risk of the pests with the benefit of natural enemies?" he said.
Hilton recently received word that he and Helmut Riedl, his entomologist counterpart at MCAREC, will be taking part in a USDA-funded program to explore the future of IPM. The goal is to take the "multi-tactic pheromone-based system revolving around mating-disruption of codling moth and trying to get as much benefit from natural enemies as possible" in the orchard.
"This is something new. We don’t know all the variables yet."
Looking to the future, Oregon’s pear growers will find profits more elusive. Stiffer competition from foreign growers is one reason. Over the past several decades, as Oregon’s commercial pear industry has grown and prospered, growers and OSU researchers have learned a great deal about how to grow first-class pears. Of course, this horticultural success story has not gone unnoticed by growers in China, Argentina and Chile, among other countries, eager to build an agricultural enterprise capable of producing delicious—and valuable—fruit. In time, foreign growers have amassed the technical know-how and secured the financial resources to create pear industries capable of producing fruit that competes against U.S.-grown fruit in global markets.
But there are other concerns as well. The fact is that Oregon growers now compete in a global marketplace that responds to forces beyond their control—or anyone’s control, for that matter. Trade barriers, currency exchange rates, political instability and economic turmoil in foreign nations, not to mention a worldwide glut of perishable fruit chasing consumers with widely divergent diets and tastes—for these reasons and others as well, many in Oregon’s pear industry are scratching their heads, trying to put together a business strategy that will bring them success in the global marketplace.
Medford grower Laura Naumes said, "Which way should the industry go? I have no idea. Twenty years ago we had a good feel for which way to go. Now, we just don’t know."
But ideas about how to help Oregon’s pear industry survive and thrive already are being floated. Some industry insiders think at least a partial answer lies in so-called value-added processing, the practice of taking raw product and processing it to produce a higher-value product—in this case, fresh pears could be turned into fruit filling for a frozen dessert or a fruit beverage.
Another idea is to expand marketing schemes aimed at increasing consumers’ consumption of fruits, including pears. One such initiative is the 5 A Day program, a public-private nutrition education campaign that encourages adults and children to eat an average of five or more servings of fruits and vegetables a day. Congress is considering industry requests to fund other such promotional programs.
But no one should forget that fundamental to the success of any business, including the business of growing pears in Oregon, is its ability to produce a top-quality product that people will want to buy. And OSU in its research and extension activities will continue to serve the state’s growers in their yearly pursuit of producing world-famous pears.