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  • Author or Editor: J.L. Olsen x
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Oregon State University (OSU) developed an integrated pest management (IPM) program for hazelnut (Corylus avellana.) in the early 1980s, through a USDA grant. Sampling schemes and action thresholds were refined over a period of 4 years for the filbertworm (Cydia latiferreana), filbert aphid (Myzocallis coryli), filbert leafroller (Archips rosanus.), and obliquebanded leafroller (Choristoneura rosaceana), which are the most important insect pests in Oregon hazelnuts. A classical biological approach was employed in the mid-1980s when the filbert aphid parasitoid, Trioxys pallidus, was imported from Europe. Grower survey results for 1981 and 1997 showed that the amount of pesticides applied for filbert aphid control has declined by 93%. The registration of synthetic pyrethroids for filbertworm control and the use of pheromone trapping have reduced the amount of active ingredient applied in the industry by 96%. The annual cost savings to Oregon hazelnut growers due to use of the OSU IPM program are estimated at $0.5 million. Current research focuses on the use of less toxic insecticides, such as insect growth regulators for filbertworm and leafroller control. The most serious hazelnut disease, eastern filbert blight (EFB) caused by the fungus Anisogramma anomala was first reported in the Pacific northwestern U.S. in 1973. It has spread its way through two thirds of the hazelnut acreage. Current OSU IPM recommendations include preventative fungicide sprays in spring, scouting for and cutting out infections, and replacement of the most susceptible cultivars when possible. The long-term approach to EFB control is the development of EFB immune varieties.

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The chestnut (Castanea Mill.) industry in the northwestern United States is in its relative infancy, with most orchards being less than 10 years of age. Currently there are an estimated 300 acres (121 ha) in Oregon and Washington. California has about 500 acres (202 ha) in chestnuts. Current worldwide production is over 500,000 tons (435,600 t). China is the leading producer with 40%, followed by Korea at 15%. Italy, Turkey and Japan grow 10% each, while France, Greece and Spain grow 4% each. The United States, Chile, Argentina, New Zealand and Australia each grow less than 1%. The value of chestnuts imported into the United States is estimated to be $10 to 15 million annually. Domestic producers hope to displace some of the imported chestnuts in the marketplace. The leading variety being grown in the western United States is `Colossal,' a hybrid between european chestnut (C. sativa Mill.) and japanese chestnut (C. crenata Gillet). `Dunstan' hybrids are chestnut blight (Cryphonectria parasitica Murr.) resistant, and were bred in Florida using chinese chestnut (C. mollisima Blume) and american chestnut (C. dentata Marsh. Borkh.) parentage. Prices received by chestnut producers in the northwestern United States have ranged from $1.20 to $7.00/lb ($2.64 to $15.40/kg). The marketing of chestnuts has been through brokers into wholesale markets, farmers markets, mail order and direct sales through catalogues and World Wide Web sites.

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In 1993, then OSU President John Byrne declared that: “All Extension Service faculty, county agents as well as specialists, will be assigned academic colleges, and will have an academic appointment in the appropriate college.” The selection of the academic home would involve a mutual agreement between the individual and the department and would take into consideration the faculty member's academic training, experience, and work assignment. The implementation of this decision was completed by July 1995. In the College of Agricultural Sciences, this assignment of faculty to academic homes was accommodated by adding county agents to the faculty of existing departments. The Dept. of Horticulture faculty numbers nearly doubled, with an increase from 34 to 58. The department head is now very involved in the annual review and salary administration of extension field faculty. Campus-based faculty are now involved in all of the hiring, promotion, and tenure decisions for extension field faculty and vice versa. Field faculty participate in departmental decision making. The change in the number and diversity of faculty in the department is a unique effort to unify programmatic focus for extension, research, and teaching at OSU. As a work in progress, many issues are being addressed including full faculty participation in the decision-making process, communication, evaluation of scholarship, and building departmental community. Successes, pitfalls, and challenges ahead will be discussed and illustrated.

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Abstract

In the 1st (1981) and 2nd (1982) fruiting years, ‘Benton’ strawberry (Fragaria x ananassa Duch.) formed 25% to 30% more crowns/plant than the advanced breeding selection OR-US 4356. ‘Benton’ had fewer trusses/crown than OR-US 4356 in 1981 (0.93 vs. 1.47) but both had 1.5 in 1982. OR-US 4356 had about 60% more fruit/truss in each season; however, ‘Benton’ had 75% greater mean berry weight than OR-US 4356, so that the 2 genotypes produced essentially the same yields/plant in each season, averaging 0.82 kg (1981) and 0.94 kg (1982). The genotypes did not differ in the total number of achenes/berry. Both showed a linear increase in berry weight with achenes/berry; yet OR-US 4356 had significantly lower berry weight than ‘Benton’ at equivalent achenes/berry. Increased berry expansion in ‘Benton’ was reflected by a reduction in number of achenes/cm2 of berry surface. The values, averaged over both seasons, were 10.6 (‘Benton’) and 14.0 (OR-US 4356). OR-US 4356 failed to produce higher yields than ‘Benton’ because of limitation in fruit expansion.

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Hazelnuts, (Corylus avellana L.), are wind-pollinated, monoecious, mostly dichogamous, and self-incompatible. About 90% of the cultivars studied are protandrous. Anthesis of the pistillate flower is temperature-dependent and occurs December through February, peaking in January. Stigmatic surfaces may remain receptive for up to 3 months. Four to 5 months separate pollination and fertilization of the ovule; the latter usually occurring between mid-May and the end of June in Oregon. A 10% pollinizer density has been the standard, with a recommended distance of 66 ft (20 m) or less between the main cultivar and the nearest pollinizer. Two or three different pollinizer cultivars, with different times of pollen shed, are recommended. The Oregon hazelnut industry is presently combating the fungal disease, eastern filbert blight, caused by Anisogramma anomala (Peck). Current management recommendations suggest reducing risk of infection are to reduce the most susceptible pollinizer cultivars to a density 5%, then gradually replace those left with immune or more resistant genotypes.

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Modeling the growth of field-grown tomato (Lycopersicon esculentum Mill.) should assist researchers and commercial growers to outline optimal crop management strategies for specific locations and production systems. A generic crop-growth model (CROPGRO) was previously adapted to simulate the growth of fresh-market tomato under field conditions. Plant growth and development of field-grown tomato, and fruit yields, will be outlined and compared to model predictions for a number of locations in Florida, nitrogen fertilizer rates, and irrigation management practices. Possible application of the model to quantify effects of crop management on crop production will be discussed using simulated yield values for a wide range of environmental conditions.

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Abstract

Field grown strawberry plants (Fragaria × ananassa Duch.) of an advanced breeding selection (OR-US 4681) were harvested every 3–4 days during establishment and through fruiting the next spring. Plant dry weight and leaf area increased rapidly during mid-summer, then slowed and finally ceased in October. Absolute growth rate (AGR) peaked at 1 g dry matter/day near 1 Sept., then fell to zero by early October. Over this period, there was a decrease in weekly mean temperature (37%), solar radiation (47%), and daylength (35%). Maximum values of relative growth rate (RGR) (0.044 g/g/day) and unit leaf rate (ULR) (9 g/m2/day) were determined at the start of sampling at the end of June; both rates declined steadily thereafter. The following April through June, both plant dry weight and leaf area increased exponentially, whereas RGR remained constant at 0.02 g/g/day, and ULR rose from 5.5 to 6.5 g/m2/day. The rate of dry matter accumulation in fruit was exponential, whereas it was linear in leaf lamina and stems (crowns plus petioles). A much smaller proportion of dry matter was partitioned to leaves during fruiting than during plant establishment.

Open Access