Oregon Blueberry Newsletter

Transcription

1 April 30, 2002 Volume 2 Issue 1 Oregon Blueberry Newsletter Tech Corner Mummy Berry Resistance Studies indicate that rabbiteye blueberry cultivars, in general, are less resistant to mummy berry blight than are highbush blueberry. Among highbush cultivars tested, Northsky, Reka, Northblue, Bluegold, Puru, and Bluejay are among the most resistant, while Atlantic and Berkeley are among the most susceptible. Nonetheless, there is no significant correlation between blighting resistance and fruit infection resistance. Blueberry Fruit Rot Studies found that sprayer type and pruning did affect the incidence of fruit rot (caused by Alternaria sp. and Botrytis cinerea) in highbush blueberries. The multifan/nozzle, above-row sprayer provided fruit rot control at least equivalent to the airblast sprayer with less chemical used. Pruning only reduced Anthracnose rot in berries harvested from the top of the bush canopy, it did not affect the level of fruit rot harvested from the bottom of the bush. Avoid Phytotoxicity of Captan and Diazinon When using Captan and Diazinon together as a tank mix, phytotoxicity on highbush blueberries can occur. The injury to fruit and leaves caused by the tank mix is much greater than that caused by separate Diazinon and Captan applications. The two should be applied separately at least 8 hours apart. Remember, Diazinon and Captan should not be applied in combination. Useful websites Blueberry production berrycrops/blueberry.htm Blueberry pollination berrycrops/blueberry/pollina.htm Pesticides for blueberry Chemical labels NE Miley Road Aurora, Oregon Edited by Dr. Wei Q. Yang Office: ext 26 wei.yang@orst.edu Dear Blueberry Grower: I hope you all had a great winter and are ready for the new season. In this newsletter, I d like to inform you on a few things happened during off-season, then talk about the new growing season. Last December, a year-end survey was sent to you along with the newsletter. So far, I got about 25% back. There is no deadline for the survey, so please mail it if you still have it. In January 2002, a Blueberry Nursery Stock Control Area for the eastern strain of blueberry scorch virus was approved by ODA; it can be found at berrycrops/blueberry/berrycontrol.htm. Recently, Abound was approved for mummy berry control and Elevate for Botrytis control in blueberries in Oregon. However, you ll need to have the supplemental label in hand when using Elevate. Remember, Indar is legal to use until 5/31/2002. The labels for these chemicals can be found at greenbook.net/asp/free.asp. Finally, I d like to mention that flower bud sets are good and winter damage seems to be minimal in fields I have visited. It looks like we are heading to a good growing season. May the year of the horse bring us luck and success. Sincerely, Inside this issue: Issues in blueberry pollination Troubling Times for OSU Extension Events 4 Blueberry Field Survey 5 Wei Q. Yang District Berry Extension Agent Editor/Webmaster of Agriculture, Home Economics, 4-H Youth, Forestry, Community Development, Energy, and Extension Sea Grant Programs, Oregon State University, United States Department of Agriculture, and Oregon counties cooperating. The Extension Service offers its programs and materials equally to all people.

2 Page 2 Issues in blueberry pollination By Wei Yang Most highbush blueberry cultivars produce satisfactory crops when planted alone in large blocks. Studies found that Sierra and Toro probably need cross-pollination for maximum yields, meaning these two cultivars need to be planted with other highbush cultivars. Because blueberry flowers are urn-shaped and usually inverted (Fig 1), the pollen in the anther is not easily accessible to bees. Bees help pollinate blueberry flowers by facilitating pollen release from the anther, thus increasing pollination efficiency (or fruit set). Bumblebees are the best pollinators for blueberries, followed by wild bees and honeybees. Nonetheless, honeybees are easier to get and much cheaper than commercial bumblebees. Pollination is often affected by the variations in corolla length and nectar number of blueberry flowers among different cultivars. As a result, the number of beehives required by different cultivars may vary accordingly. Table 1 summarizes the number of beehives required for adequate pollination for some blueberry cultivars. Adequate pollination is required to achieve desirable fruit set. Table 1. Number of beehives Cultivars Beehive per acre z Rubel 0.5 Bluetta 1 Blueray 1 Darrow 1 Bluecrop 1.5 Berkeley 2 Elliott 2 Jersey 2.5 Earliblue 2.5 Z A strong hive requires a minimum of 45,000 bees In general, there is adequate pollination activity if you observe fifteen to twenty bee entries into blueberry flowers within a ten-minute period (according to Dr. Gough). Pollinated flowers stay white and drop within 4-5 days after bloom. If flowers have not been pollinated within the critical few days (usually three) after flower opening, Fig 1. A blueberry flower they will remain open on the bush for 1-2 weeks and turn a brilliant wine color. Fruit set is then unlikely for those longer-lasting flowers (according to Dr. Gough). Since bees become more active with increasing air temperature, hives should be placed at a sunny spot with Corolla their entrances facing east to encourage early bee activity. Insecticides should be avoided around beehives and during bloom period. Place a cup of drinking water near the beehives to maintain bees energy. Hives should be brought in when 5% of the flowers have opened. Bees may look elsewhere if hives are brought in too early, thus reducing their pollination efficiency later on. Wild flowers (e.g. dandelions) should be eliminated for a similar reason. During the 2001 growing season, there were some concerns about the possibility of poor pollination by bees in the highbush blueberry cultivar Rubel. One way to know whether adequate pollination has occurred is to determine pollen load on the surface of stigma, which requires chemical dyes and microscopic examination. Another is to simply count the number of seeds in the berry following fruit set, since inadequate pollination would likely result in fewer seeds in the berry. The latter approach was used to determine if bee activities had any effect on pollination in cultivar Rubel. The following three Rubel fields were sampled one month after fruit set. Field 1, 26-year-old Rubel with normal bee activity; Field 2, 2-year-old Rubel with normal bee activity; Field 3, 2-year-old Rubel with little reported bee activity. Two samples were collected in Field 3; one from rows treated with ProGibb at full bloom, the other from untreated rows. For each sample, twenty berry clusters were randomly collected from the top of the bush from different plants. The berries from all 20 clusters were pooled, and one

3 Page 3 hundred berries were then randomly selected for seed count. The final seed count from all three Table 2. Seed number in cultivar Rubel Rubel fields fields is listed in Table 2. Seed number Field 1 (26-yr-old ) Field 2 (2-yr-old ) Field 3 (2-yr-old + control ) Field 3 (2-yr-old + ProGibb ) In Field 3, no difference in seed number was found between ProGibb treated berries and untreated ones. It suggests that ProGibb application did not have any effect on pollination or creating parthenocarpic (seedless) berries when applied at full bloom. ProGibb is known to increase fruit set in some rabbiteye blueberries, but its usefulness in increasing fruit set in highbush blueberries has not been demonstrated under the growing conditions in Oregon. Although the level of bee activity was different between Field 2 and 3, the same seed numbers between the two fields suggest that the little reported bee activity in Field 3 did not affect pollination in cultivar Rubel. The older Rubel in Field 1 has 10% fewer seeds per berry than both the young Rubel fields, but berry yield of the older Rubel was not affected. Because all three Rubel fields had normal fruit set and berry yield, pollination in cultivar Rubel should not be an issue to be concerned about. In fact, Rubel is a cultivar attractive to bees with only one beehive required for every two acres of planting (Table 1). Troubling Times for the OSU Extension Service By Diane Kaufman With revenues down in these difficult times, many state agencies and programs in Oregon are facing cuts. The original budget proposed by the legislature a few weeks ago would have resulted in about a 10% cut in funding for the OSU Extension Service for the fiscal year beginning July 1,2002. Although these cuts would have been painful, they would probably have been manageable. Because Governor Kitzhaber was unhappy with the budget proposed by the legislature, he proceeded to make additional cuts to targeted programs. The Governor's proposed targeted budget reductions would result in a 25% cut in this biennium to both the Extension Service and the Agricultural Experiment Station. Since the biennium is nearly half completed, to accomplish this, we would each need to cut our budgets by 50% beginning July 1,2002. A 50% cut in one year would be devastating and probably destroy the Extension Service, at least as we know it today. Should a 50% cut become necessary, no one in the organization has any idea how or where these cuts would be made. I imagine that the OSU Extension Service would probably be able to absorb the bulk of a 10% cut in one year through unfilled positions and attrition. However, there is no precedent for administering a cut as severe as 50%. In such a situation, the jobs of all Extension Service employees would be in jeopardy and no one can say what would be left of the OSU Extension Service or Agricultural Experiment Station once the cutting was over. Those researchers and agents remaining in the organization would find it very hard to accomplish much without infrastructure or support. Because the situation we face is so dire, it is important that clientele concerned about the future of our programs consider writing letters of support to legislators and to Governor Kitzhaber. In a directive sent by Lyla Houglum, Dean of the OSU Extension Service, she suggests that clientele thank legislators for their past support and their attempt to keep the budget reductions to 5% (10% concentrated into one year). She also suggests that letters focus on the value that Extension programs provide and why these programs are important to Oregon. If there are special research projects or educational programs clientele have found particularly important or valuable, it would be good to refer to these specific programs and explain how they have been beneficial. Lyla suggests that letters to the Governor focus on the value of Extension programs and the importance of these programs to the people of Oregon, citing specific programs of particular benefit to clientele. She suggests that the letters to Governor Kitzhaber indicate that a 25% cut (50% in one year) is not acceptable and ask that the Governor work with the legislature to come up with an acceptable solution. Lyla also suggests that clientele consider writing a letter to the editor of their local newspaper outlining the current situation and the value of Extension programs to the community. Letters to the Governor should be addressed to: Governor John Kitzhaber State Capital Building 900 Court St. NE Salem, OR

4 Page 4 1 May 18, 2002, Oregon Blueberry Growers Association (OBGA) will have its annual meeting at Roth's IGA (Santiam Room) - West Salem from 6:00-9:30PM. Mark D. Hurst will be honored at the meeting as the "Outstanding Leader in the Oregon Blueberry Industry". Special guest, Mark Villatta, the Executive Director of NABC will be attending the meeting. For registration, please call Judy at May 24, 2002, Blueberry Production Workshop and Tour OSU Extension Service will present a workshop on blueberry production at the Pine Grove Grange in Hood River on Friday, May 24. The workshop will address several aspects of blueberry production including cultivars, site selection, soil, nutrition, irrigation, trellising, harvest methods, and economics. The morning workshop will be followed by an afternoon tour of several existing blueberry plantations in the Hood River area. Coffee and donuts will be available from 7:30 to 8:00 AM. The workshop program will run from 8 AM until noon. The afternoon tour will run from approximately 1:30 to 4 PM. For more information, contact the OSU Extension Office in Hood River at The workshop agenda is listed below. 7:30 AM Coffee and Donuts Provided Courtesy of UAP Northwest 8:00 AM Welcome and Introductions Steve Castagnoli, Extension Agent, OSU MCAREC 8:10 AM Pre-plant Considerations for Blueberry Production Dr. Bernadine Strik, Berry Crops Specialist, (site, soil, nutrition, cultivar, spacing, trellising, OSU NWREC designing for harvest method) 9:40 AM Irrigation Methods for Blueberry Dr. Wei Yang, Extension Agent, OSU NWREC 10:10 AM Break 10:30 AM Irrigation Scheduling for Blueberry Dr. Roberto Nunez-Elisea, Horticulturist, OSU MCAREC 11:00 AM Blueberry Disease Management Dr. Jay Pscheidt, Extension Plant Pathologist, OSU Corvallis 11:30 AM Blueberry Economics - Costs of Establishment Clark Seavert, Extension Agent and Superintendent, and Production OSU MCAREC 12:00 PM Lunch on your own 1:30 PM Tour of Hood River Area Blueberry Plantations 4:00 PM Adjourn OSU Blueberry Newsletter North Willamette Research & Extension Center NE Miley Road Aurora, Oregon BULK RATE U.S. POSTAGE PAID AURORA, OR PERMIT #44 Return Service Requested

5 Page highbush blueberry field survey in Oregon cultural practices By Wei Yang The Oregon highbush blueberry industry is well-established with its production and processing scale and the breadth and diversity of its markets. Because of the differences in farm size, soil type, and cultivars planted, the cultural, disease, and soil fertility management practices vary greatly among growers. In some blueberry fields, plants show weak growth without obvious aboveground disease symptoms (personal observation). Investigations into blueberry root systems and soil pathogens seem to be a logical approach to determine if the weak growth could be explained by some of the belowground variables. With the recent discovery of the eastern strain of blueberry scorch virus in British Columbia, there is a need for an industry wide field survey to gather information on cultural practices and blueberry scorch virus to identify production problems and future research/extension program priorities for the blueberry industry in Oregon. The goal of this survey was to determine the state of cultural practices in highbush blueberry production and how cultural practices may affect soil and plant health. Survey development and sampling methods The survey was initiated by Dr. Jack Pinkerton and the author with the participation of Dr. Robert Linderman, Dr. Carolyn Scagel, and Dr. Robert Martin from the Northwest Center for Small Fruit Research. The survey team consisted of USDA scientists who have expertise in nematode, phytophthora root rot, mycorrhiza, and viral disease research. The survey therefore was developed to target specific research areas to complement each scientist s expertise and research interests. Information on cultural practices and soil and leaf samples were collected from more than 70 commercial blueberry fields in the Willamette Valley in fall Root, soil, and leaf samples were processed at the Horticultural Crops Research Laboratory in Corvallis, OR. Cultural management information was collected either during or after taking soil and leaf samples. Soil samples for nutrient analysis were collected randomly from five plants from each field and analyzed by OSU s Central Analytical Laboratory. The results from cultural practices are presented in this report. The rest of the survey results are presented by each scientist elsewhere in this proceeding. Results and discussion The survey found that 93% of highbush blueberry fields are irrigated by overhead sprinkler irrigation (Table 1). Drip irrigation constitutes the remaining 7% and no microsprinkler irrigations are used. It seems that the merit of using drip systems over overhead irrigation is debated among growers, because some growers replaced drip with overhead systems. For those still using drip systems, two drip lines are often used to keep up with the water demand by plants. Irrigation scheduling is generally empirical regardless of the irrigation methods. Over-irrigation could be a potential problem that needs to be monitored and addressed in the future. Studies with highbush blueberries in the East Coast found that drip irrigation used 54% less water and 74% less energy per growing season as compared to overhead irrigation (Funt et al., 1980). Thus the water and energy savings of using drip irrigation should be evaluated in highbush blueberry production in Oregon. Table 1. A summary of cultural practices of highbush blueberry fields surveyed in 2001 Irrigation Bed OM addition* Row cover Soil pesticide Soil ph Available soil N 93% Overhead 2 Raised 55% Yes 95% Grass 6% Yes 24% > ppm NH 4 7% Drip 78% Flat 45% No 5% None 94% No 7% <4.5-3 ppm NO 3 * Meaning use of organic matter (OM) as either mulch or soil amendment.

6 Page 6 Another related issue to irrigation is the use of raised vs. flat beds. About 80% of the fields have flat bed for production. The combination of overhead irrigation and the flat beds increases the potential for phytophthora root rot due to poor drainage. During the survey, it was easily noticed that plants sitting in the lower areas of a field usually showed weak growth, which often points to root related problems. Soil organic matter is very important for highbush blueberry productions (Chandler, 1942; Clark, 1936; Gupton, 1985; Patten et al, 1988; Goulart et al., 1996). More than half of the fields surveyed show that organic matter was added to the soil by either amendment or surface mulch. This cultural practice should be encouraged, particularly under very low soil ph (<4.5) conditions to help reduce free soil aluminum. Almost all the fields surveyed have grass row cover and do not use soil pesticides. For those fields without grass row cover, it should be considered since grass row cover helps control Berkely Bluetta (13 yr old) Blueray 5% Elliott (8 yr old) 7% Earliblue 8% (12 yr old) Brigitta 8% (7 yr old) Bluejay Darrow Spartan Rubel 14% (3 yr old) Duke 33% (9 yr old) Bluecrop 13% (15 yr old) weeds and reduce soil compaction caused by farm machinery. Although most of the fields managed their soil ph well, about 30% of the fields are still having ph values either more than 5.5 or less than 4.5. It is widely accepted that the best soil ph range for highbush blueberries is between 4.5 and 5.5. Therefore, monitoring soil ph level is one of the most important cultural practices should never be overlooked. It is very interesting to note that the average ratio of soil ammonium to soil nitrate concentration is very large (243:1). This may be expected because ammonium based nitrogen fertilizer is often used for blueberry production. The low nitrate levels could be a result of low nitrification rate or excessive leaching, however, these scenarios have not been studied in highbush blueberries in the Pacific Northwest. Cultivar distribution indicates that Duke is the number one cultivar (33%) in production, followed by Bluecrop, Rubel, Brigitta, Earliblue, Elliott, Blueray at 13%, 14%, 8%, 8%, 7%, 5% respectively (Fig 1). Most of these cultivars are in their peak producing age except Rubel, which averaged 3-years-old. This indicates Rubel is a new popular variety to be planted widely, probably due to its attractive small berry size for processing needs. In summary, the survey has provided valuable data for the state of the highbush blueberry industry. The irrigation and soil organic matter data have been used for developing new research projects (grant writing). The potential areas for future educational programs have also been identified. These include irrigation-related issues, the importance of soil organic matter, and soil ph management. Therefore, the survey has identified production-related problems and future research/extension program priorities for the highbush blueberry industry in Oregon. Toro