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Practical Grower
Hood River station immersed in pear research
I've been the Oregon State University Extension Service hort agent in Hood River for just over two years. Because I didn't have much of a pome fruit background when I took this job, these last two years have included large, daily doses of "agent training." The road to wherever I am today would have been much more difficult if I had been isolated from expert colleagues.
Fortunately for me, the Hood River office of OSU Extension Service is on the grounds of the Mid-Columbia Agriculture Research and Extension Center (MCAREC). I have been able to wander across the parking lot to ask questions of some of the world's leading authorities on pear production and handling. I can also ask questions of Clark Seavert, OSU Extension Service farm management area agent, regarding orchard economics and the structure of the pear industry in general.
So, it makes sense that my first contribution to "The Practical Grower" highlights the most recent achievements of the research faculty and staff at MCAREC, with a focus on pear production.
The Mid-Columbia Agriculture Research and Extension Center in Hood River is the only experiment station in the United States that specializes in pear production. The research faculty at the station includes Drs. Gene Mielke (superintendent/horticulture), Tim Facteau (horticulture), Bob Spotts (plant pathology), Paul Chen (postharvest physiology), and Helmut Riedl (entomology). All of these researchers have at least ten years' experience in Hood River. Research money provided by the Washington Tree Fruit Research Committee, the Winter Pear Control Committee, and the Hood River Grower Shipper Association funds a great number of research projects, both on the station and in nearby growers' orchards.
Postharvest problems
The biggest problems facing the Mid-Columbia pear industry are postharvest decay and poor d'Anjou fruit finish. Tim Facteau has spent a great deal of time working on pear finish problems while spending most of his time on research to support the cherry industry in the Mid-Columbia region. In 1996, Facteau, working with Gene Mielke, showed that high rates of mancozeb (six pounds per acre) improved d'Anjou packouts (increased percentage of U.S. No. 1 pears), compared with lower rates (three pounds per acre). This season, he is continuing to work on russet reduction programs. This year, Facteau was awarded the Hartman Cup, Oregon Horticulture Society's highest award, for his thirty years of very valuable contributions to Oregon horticulture.
IFP
There has been a fair amount of discussion lately concerning integrated fruit production (IFP), the marketing of IFP fruit, and just what "real" IFP is. The concept of IFP is one that few people can argue with--a way of thinking about farming that recognizes the linkages between different practices. One Hood River field representative calls IFP by another name: "Intelligent Farming Practices."
Helmut Riedl, the MCAREC entomologist, has spent a significant amount of time over the past three or four years working with Hood River growers on IFP practices and concepts. It was he who first brought IFP to Hood River after visiting the South Tyrol region of northern Italy, where a strict IFP program has been in practice for a decade or more.
With research grants from Hood River Grower Shipper Association and the state of Oregon, Riedl and his assistant Deanna Neal are working with growers in four commercial orchard sites in Hood River. These research and demonstration blocks are established as on-farm tests where IFP practices can be evaluated side-by-side with
These tests include:
--pheromone mating disruption for codling moth control compared to organophosphate cover sprays;
--alternating miticide treatments to reduce the chance of resistance development to a particular product. Mating disruption works in pears, though it is expensive. So does alternating mite control materials, and most IFP blocks have not needed summer pear psylla control. There have been unexpected developments--leafrollers and pear rust mites to name two--but it is better to learn this with open eyes in a research and demonstration block than to be blindsided when a spray material is pulled or fails.
Clark Seavert has been involved in the IFP research and demonstration project from the beginning. He has shown that, under current costs and chemical registrations, the IFP spray program is significantly more expensive than the conventional programs. It remains to be seen how the economics work out in five years after the consequences of the Food Quality and Protection Act are felt.
Insect problems
In addition to his involvement in the IFP demonstration project, Riedl's research program focuses mainly on the insect and mite problems Mid-Columbia growers have to face every year. Together with his assistant Deanna Neal, he conducts a large annual testing program to evaluate new pesticides and other controls against major pests of pears, apples, and cherries, including codling moth, pear psylla, spider mites, pear rust mite, leafhoppers, aphids, leafrollers, and San Jose scale.
Codling moth control has been a major focus. New, selective materials for codling moth control are being evaluated, including insect growth regulators, such as Confirm (tebufenozide) and Comply (fenoxycarb); mating disruption;, and the microbial insecticides Bt (Bacillus thuringiensis) and granulosis virus; as well as using mineral oil to kill codling moth eggs. In addition, Riedl and his staff are studying how codling moth behave in order to learn how to better control this key pest.
Scab model
Bob Spotts, the MCAREC plant pathologist, is also working on integrated approaches to pear pest control. A good example of this is his work in pear scab control. Over the last decade, Spotts has developed a computer model to predict when pear scab infections will occur, based on leaf wetness and temperature data. This computer model is being evaluated in several commercial orchards in Hood River. In addition, he and his assistant, Louis Cervantes, have developed a model to tell growers when primary scab infection risk is over (usually early June in Hood River) and scab protection is no longer important in orchards that have been kept clean all spring. Spotts has also found that dolomite lime applied to
the orchard floor after leaf drop (over the fallen leaves) reduces spring spore counts by 50 to 90%, depending upon the year and rate of lime applied. This doesn't mean there is no need for spring scab sprays to control scab, but fall liming over the top of fallen leaves does reduce spring scab pressure. All these research results contribute to informed orchard management, the central theme of IFP.
Postharvest decay
Postharvest pear decay is a major focus of Spotts's work. A great deal of work in his lab has been developing biological control methods for postharvest decay (blue mold, gray mold, bull's-eye rot, etc.).
These materials may soon complement or replace certain fungicides in the packing house. In addition, Dr. Cheryl Lennox, has been working with Spotts and his staff to try to understand where, when, and how gray mold infects pears. This will be the work on the subject when the project is completed in 1999. Bob also has shown that 15 pounds of Nutraphos-24 per acre at three weeks before harvest significantly reduces blue mold infection in d'Anjou pears compared with unsprayed fruit.
Pear ripening
Over the years, some of the most important research in postharvest pear handling has come from MCAREC. A major reason for this has been the work of Dr. Paul Chen. In the mid-1990s, Chen and his assistant Dianne Varga continue world-class work into ripening characteristics (Bartlett, green and red d'Anjou), scald prediction for d'Anjou, and storage practices for scald, pithy brown core, and black speck prevention. In the last few years, Chen has shown that Gebhard Red d'Anjou needs ethylene to soften, Bartlett pears should be held in cold storage for three to four weeks after harvest to ripen uniformly without added ethylene, and has done key work on preripening of green d'Anjou pears. Paul's preripening work shows that d'Anjou pears will soften to good eating firmness if held in cold storage for six to ten weeks after harvest, or exposed to ethylene in a warm room for two days after three to eight weeks of cold storage following harvest, or exposed to ethylene and warm temperatures for three days after zero to three weeks of cold storage before cooling and shipping. Chen strongly believes that the goal of preripening is to ship a ripening pear, not a soft, easily damaged pear. This means a firm pear (8-12 pounds) at the end of transport and a soft, ready-to-eat pear (1-2 pounds) after a week or so of shelf-life. Quality to the consumer will be a key to continued successful pear growing, and Chen works directly on this subject.
Orchard systems
What will the pear orchard of the future look like? Stop by the MCAREC, and you just might see it. Since the mid-1980s, Mielke and his staff, led by Laurie Smith, have been looking at pear rootstock, scion, and training system combinations. Trellis (Tatura V and MIA [inverted] V), vertical post and wire systems (modified central leader, palmate, spindle, and Marchand), and freestanding central leader systems are being evaluated on new pear varieties such as Red d'Anjou, russet Bosc, red Clapp, and Cascade, as well as green d'Anjou. New plantings at MCAREC are now done with a single, 12-foot high wire and light posts at each tree to stabilize the leader and provide tying points for branch supports.
What rootstock does Mielke like or green d'Anjou? While trees on Old Home by Farmingdale (OHxF) 97 have produced as well as other rootstocks, OHxF 87 produced double the crop of OHxF 97 in the fifth leaf. (Spreading is key to early bearing for pears on OHxF rootstocks.) The annual production advantage did not last beyond the sixth leaf in Mielke's trial, but as Clark Seavert has taught me, the time-value of money makes this early difference something to consider. While OHxF rootstocks other than 97 and 333 were difficult to obtain in the past, adaptation of new propagation techniques means that OHxF 87, 69, and 40 are and will be available options for growers.