Status Update on Organic Blueberries in Michigan

Abstract

The Great Lakes Region is an important region of blueberry production in the U.S., producing 30% of the annual U.S. production. In Michigan, blueberry acreage increased from 17,724 acres on 590 farms in 2002 to 21,758 acres on 840 farms in 2007. However, despite considerable market potential for organic blueberries, less than 1% of total Michigan blueberry acreage is organically certified. There is high interest and demand for organic blueberries from the Great Lakes Region, and the Michigan State University Blueberry Team has been working on organic production methods over the past 4 years. The establishment of the Michigan State University Organic Blueberry Research and Extension Planting on the Michigan State University campus has been one of the major accomplishments of the Michigan State Uuniversity research team. The objective of this project has been to study practices associated with soil health, nutrition, disease, and insect and weed control. Additional organic blueberry projects in Michigan have focused on studying the interaction of blueberry mulches and compost on nutrient release, and on-station and on-farm testing of OMRI-approved pesticides.

Keywords:

• mulch
• insecticide
• soil biology
• fertilizer
• cover crops

INTRODUCTION

High consumer demand for organically produced fruit, perceptions of increased marketability and value of organic blueberries, and concerns over the safety of conventional inputs have motivated Michigan highbush blueberry growers to consider organic production practices. Michigan growing conditions are perceived to be favorable for organic production as highbush blueberries are a native plant. Spodosols, acid sands, and mucks are present in several regions within the state and there are several major metropolitan areas in the region to provide a marketplace for organically produced berries (Chicago, Grand Rapids, Detroit, Lansing). However, despite Michigan being a major blueberry production region (Kleweno and Matthews, 2008), only 60 of Michigan's over 19,500 acres of blueberries are presently certified organic (Michigan Department of Agriculture, personal communication).

Potential reasons for the low percentage of certified organic blueberry acreage in Michigan include: lack of resources regarding organic production methods, challenges related to organic management of weeds, pests and nutrients, and lack of an established organic marketplace for wholesale organic blueberries (Bingen et al., 2007). Faculty and staff at the Michigan State University departments of Horticulture, Plant Pathology, and Entomology and Michigan State University Extension have recently established research and extension programs to address these issues to support the further expansion of organic blueberries in Michigan and the Great Lakes region. Some of our research efforts are outlined in this article. Our efforts have included: (1) surveying growers on the amount of certified and transitional organic acreage within Michigan, (2) their research and extension needs, and (3) research trials on organic nutrient, weed, insect pest, and pathogen management.

MATERIALS AND METHODS

Grower Questionnaire

We developed and administered an informal grower questionnaire at an organic blueberry extension meeting on December 18, 2009. Attendees were asked whether they produced organic blueberries or were interested in organic production. Also they were polled concerning their current blueberry acreage under organic transition or certification. Respondents were also asked to rank the following areas of organic production in the order of which should receive the most needed research and extension attention: nutrient management, weed management, insect pest management, vertebrate pest management, compost and/or compost tea production, food safety, marketing/economics, labor, or other.

MSU Organic Blueberry Planting

An organic blueberry planting located at the Michigan State University campus has been under organic transition since 2007. The majority of the planting was certified in the fall of 2010. The specific research objectives for the planting have been to monitor: (1) nutrient management practices and different cover crop plantings on soil and plant nutrition, (2) surface mulches for weed control, (3) disease and insect pest prevalence, and (4) soil biological characteristics.

Cover crops and nutrition experiment

The MSU organic cover crops and nutrient management plot was initiated in 2008 in a newly-planted field of ‘Bluecrop’ blueberry to compare three cover crops (cereal rye, crimson clover, and alsike clover) and three fertility treatments: conventional fertilizers (ammonium sulfate and potassium sulfate); compost (dairy based, Morgan Composting, Evert, MI); and pelleted organic fertilizer (8-1-1, McGeary's Organics, Lancaster, PA, USA). The experimental design was a split plot with main plots consisting of different cover crops and split plots consisting of nutrition treatments. Main plots were replicated four times in a randomized complete block design. Cover crop plots consisted of 16 bushes each, and nutrition split plots contain 5 bushes each. Rates of each material were adjusted to supply comparable amounts of available N as the conventional recommendations (20 lb N/acre for each year in the field) (Hanson and Hancock, 1996), by assuming a 50% mineralization rate for the organic fertilizer and a 25% rate for the compost. The conventional and organic fertilizers were split into two applications (bud break, late bloom) whereas all compost is applied at budbreak. Row middles were maintained in fall-seeded annual rye, and the plots were weeded by hand and trickle irrigated as needed. Plant nutrient status was determined by leaf tissue analysis for N (Kjeldahl) and other nutrients (emission spectroscopy). Soil N (ammonium, nitrate) dynamics were monitored by soil sampling on five dates each year, between April and October. Each sample consisted of a composite of ten 20-cm-deep cores collected with a 2-cm-diameter soil probe. Soils were dried, homogenized, extracted with 1 M KCl, and analyzed for nitrate and ammonium by colorimetric methods. Soil quality parameters were assessed by collecting a composite soil sample from each plot in September of 2009. Data analysis was performed using Analysis of Variance.

Mulch Experiment

The mulch study at the MSU organic planting was initiated in 2008 to compare nine surface mulch materials spread beneath ‘Elliott’ bushes: (1) hand weeded control, (2) perforated plastic needs better description, (3) woven black plastic weed ground cover, (4) chipped local landscape brush (2–4 inches deep), (5) fresh pine wood chips (2 inches deep), (6) pine bark nuggets (4 inches deep), (7) wheat straw (6 inches deep), (8) aged grass hay (6 inches deep), and (9) burlap coffee sacks from a local roaster, laid flat. The design was a randomized complete block with 5-bush plots and four replications. Mulches were put in place after planting in May 2008. Plots received surface applications of pelleted 8-1-1 fertilizer (McGeary's Organics) each May at recommended rates. Additional materials were applied as needed to suppress weeds as well as weeded by hand. Total time spent weeding was recorded and a cost of $10 per hour assessed.

Soil fungi and Bacillus spp

Soil samples were collected on October 30, 2008 and on October 29, 2009. Eight soil cores were collected at 0–10 cm (0–3.9 in.) depth and 2.5 cm (1 in.) diameter 20–30 cm apart within each plot. Soil was placed in one-gallon polyethylene zipper bags, transported in chilled coolers, and stored at 4°C for up to 10 days. Soil dilutions were prepared by adding 10 g field-moist soil to 90 mL phosphate-buffered saline in 125-mL flasks and shaking at 128 oscillations per minute for 30 min. Dichloran Rose Bengal Chlorotetracycline (King et al., 1979) with chloramphenicol substituted for chlortetracycline was used to isolate fungi. Heat treatment and 1/10th-strength tryptic soy agar (TSA) were used to isolate Bacillus spp. bacteria (Bashan et al., 1993). Plates were incubated in the dark at 22°C. Colony numbers were assessed after 3 days for Bacillus spp. and after 7–10 days for fungi. Soil pH was determined on 5 g soil in a 1:1 (m/v) deionized water:soil mixture after shaking for 1 min and allowing soil particles to settle for 30 min. Leaf spot and twig dieback occurred at low levels in 2009 and were assessed on September 25 but were not significantly affected by the cover crop, fertilization, or mulch treatments (P < 0.05). Cover crops, fertilizers, and interactions were analyzed as a split-plot design in the GLIMMIX procedure in SAS (SAS Institute, Cary, NC, USA). Block and the cover crop by block interaction were designated as random effects. The block by cover crop by fertilizer interaction was specified as a within subject factor for the effect of year. Soil pH was included as a covariate to account for random field variability as main effects of nutrients and cover crops were not significant (P > 0.05). Data were square-root or natural log-transformed to satisfy distributional assumptions of ANOVA. If significant interactions between fixed effects were observed, simple effect means were compared with the SLICE option of the LSMEANS statement with a Tukey-Kramer adjustment to correct for multiplicity.

Insect Infestation

During fall 2009, bushes in the nutrient trial at the organic blueberry planting were assessed for insect infestation. The main sources of infestation observed were the blueberry leafminer, Caloptilia porphyretica, and feeding from Japanese beetle, Popillia japonica. To assess their abundance in the different plots, three bushes per sub-plot were sampled, and the number of leaves infested with leafminer or damaged by Japanese beetle were counted. The number per sub-plot was averaged across the three bushes, and these counts were compared among cover crops and fertilization regimes using a two-way ANOVA.

OMRI Japanese Beetle Spray Trial

This spray trial took place in a mature ‘Jersey’ blueberry planting at the Trevor Nichols Research Complex in Fennville, Michigan. Sprays were applied to foliage of three-bush plots on September 24, 2009 using a CO₂-powered backpack sprayer operating at 50 psi in a volume of water equivalent to 80 gallons of water per acre. Treatments included four replicates each of Aza-Direct (16 oz per acre), Aza-Direct (32 oz per acre), Pyganic 1.4EC (32 oz per acre), Pyganic 1.4EC (64 oz per acre), Surround WP (25 lbs per acre), and an untreated control. Two mature shoots on the center bush of each plot were loosely bagged with a gallon ziplock one day after treatment (DAT) to eliminate chemical wash-off as a variable in this experiment.

Bagged shoots (thinned down to 10 leaves per shoot) were taken off bushes at 1 day after treatment and 4 days after treatment and placed in a water pick (Aquapic® brand, #49-47, 4½′′ length) that was inserted into a hole cut into the bottom of a 32 oz deli cup. One female Japanese beetle (collected from the field 2 weeks earlier and fed on a diet of sassafras leaves and apple slices until use in the experiments) was added to each cup and allowed to feed for 48 hr. At the 48-hr point, beetle health was assessed on a scale of 1 to 4 with 1 being dead, 2 being twitching and dead, 3 being twitching and alive, and 4 being alive. Those recorded as being twitching and alive were showing some signs of sublethal chemical poisoning (legs dragging, slow movements, etc.) but were still able to move around. Those recorded as twitching and dead were clearly close to death (on their backs on the bottom of the cup, legs curling up, etc.), but were still technically alive. After the initial beetle health assessment, the foliage was assessed for feeding damage beginning with trace feeding and increasing in 5% increments. Assessments were conducted by two observers with the average of these two assessments being used in data analyses. Percentage damage data were arcsine square root (p ^1/2) transformed before being subjected to ANOVA followed by Fisher's Least Significant Difference test for post-hoc comparison of means (Statview, v 5.0.1, Cary, NC, USA). Japanese beetle health assessment data were analyzed using ANOVA followed by Fisher's Least Significant Difference test for post hoc comparisons.

RESULTS AND DISCUSSION

Grower Questionnaire

We had 11 respondents to our questionnaire, 9 of who indicated that they had either transitional or certified organic acreage and one who indicated that they were considering growing organic blueberries. Respondents indicated that they had a total of 33.5 acres of new blueberry plantings and 33.5 acres of mature blueberry plantings in transition with an additional 14 acres of new plantings and 2 acres of mature plantings already certified. The average new planting in transition, new certified planting, mature planting in transition, and mature certified planting were 8.4 (n = 4), 4.6 (n = 3), 11.2 (n = 3), and 2 (n = 1) acres, respectively. Weed and nutrient management were indicated as the top grower priorities for future research and extension with both categories indicated as having being a top three priority in seven instances. Insect and pathogen management received six “top three” spots, followed by vertebrate management and compost and compost tea production, marketing, food safety, and labor, which received five, five, four, three, and three top three priority rankings, respectively. Two of the respondents did not respond to this question, three did not rank all of the categories, and two simply indicated the categories of interest. One grower indicated that alternative sources of pollinators should be a top research priority.

Results of this survey indicated that the amount of known certified organic acreage in Michigan will more than double within the next 3 years. Grower concerns with nutrient management, weeds, insect pests, and pathogens were consistent with personal communications among extension staff and individual growers. The apparent grower interest in compost teas was an interesting development and suggests that more research is needed in this area, especially considering the variable results reported in trials utilizing compost teas. Research and extension on food safety was the lowest grower priority and marketing was also surprisingly low. This may be attributable to the relatively small size of the organic plantings maintained by the respondents, which likely results in a marketing plan based on selling directly to consumers rather than one dependent on wholesalers requiring Good Agricultural Practices (GAP) certification.

MSU Organic Blueberry Planting

Cover crop and nutrition experiment

Neither the crimson or alsike clover established evenly across the experiment, which prevented us from analyzing cover crop effects, and in the fall of 2009 all rows were seeded to cereal rye. Cover crop failure resulted mostly from lack of moisture in the row middles, since irrigation was supplied with trickle only under the blueberry bushes. Nitrate and ammonium levels at the organic blueberry planting varied considerably among the three nutrient management regimes. In 2008, plots receiving compost had approximately 8 ppm soil inorganic nitrogen content during May and early June, while the two fertilizer treatments averaged approximately 3 ppm during this same time frame all three treatments fell to approximately 1 ppm in late June. The low levels of nitrate and ammonium found in the two fertilizer regimes prompted us to double our fertilizer rates in 2009. Soil inorganic nitrogen content among nutrient treatments was somewhat more comparable in 2009 with approximately 10 ppm found in the compost treatment between April and early June and 6 ppm found in the other tow treatments. Leaf nutrient analysis performed in 2009 showed a similar pattern with only the compost amended plants showing a sufficient level of nitrogen (Table 1). Thus, compost appears to provide the best levels of available nitrogen but may also raise soil pH, thereby necessitating additional sulfur applications.

TABLE 1 Effect of 2008 and 2009 Fertilizer Applications on 2009 Leaf Nutrient Levels at the MSU Organic Blueberry Planting

	%					PPM
	N	P	K	CA	MG	ZN	MN	FE	CU	B
Compost	1.84	0.11	0.81	0.28	0.13	9	86	42	1.1	23
Conventional	1.48*	0.09	0.65	0.34	0.17	10	58	37	1.0	16
McGeary	1.53*	0.09	0.64	0.34	0.17	10	67	37	1.1	16
*Denotes deficient levels of nitrogen.

Organic Mulch Experiment

All mulches reduced hand-weeding costs compared to plots without mulch (Table 2). Hours spent weeding per acre were estimated at 118 hrs for the no mulch treatments with only 23 and 28 hours for the wheat straw and spoiled grass hay mulches. Fresh woodchips, bark chips, and burlap sacks performed similarly with 42, 45, and 46 hr spent weeding, respectively. Fifty-three and 74 hr/acre were spent weeding on white and black weed barriers, respectively. Bark nugget mulch plots were weeded for 61 hr/acre. The lower level of reduction in weeding time observed for the plastic mulches compared to the other mulches were somewhat surprising but were likely due to a high level of weed root infiltration under the mulch. Other studies have shown that plastic mulches utilizing a machine that “tucks” the edges of mulches 2–3 inches into the soil can reduce this problem. The relative success of the hay-based mulches is encouraging as hay is widely available and reasonably priced. However, a study completed in Georgia on rabbiteye blueberries indicated that pine straw mulches may need to be reapplied every 1 to 2 years, which would lessen the realized economic benefits (Krewer et al., 2008).

TABLE 2 Labor Costs Associated with Hand Weeding on Nine Different Groundcover Treatments at the MSU Organic Blueberry Planting in 2008 (Assumes Pay Rate of $10/hr)

Ground cover/mulch	Weeding time (hr/hectare)	Labor cost ($/hectare)
No mulch	291	2,915
Perforated plastic mulch—white	131	1,309
Woven weed barrier—black	183	1,828
Wood/bark chips	111	1,112
Fresh wood chips	104	1,037
Pine bark nuggets	151	1,507
Wheat straw	57	568
Spoiled grass hay	69	692
Burlap sacks	114	1,136

Soil Fungi and Bacillus spp

Significant fertilizer by year interactions were observed for populations of soil fungi. Fungal populations were not affected by fertilizer treatments in 2008, while in 2009 fungi were more abundant in McGeary's compared to synthetic fertilizer but not significantly different between compost and McGeary's or compost and synthetic fertilizer treatments (Fig. 1). Bacillus spp. were not affected by treatments in 2008 or 2009 (Table 3).

FIGURE 1 Average (+SEM) colony forming units collected from plots fertilized with McGeary's organic fertilizer, compost, or conventional fertililzers for: (a) bacillus and (b) fungi from soil collected at the MSU organic blueberry planting. Bars within a year with different numbers differed significantly (p = 0.05).

TABLE 3 Analysis of Variance Significance and Interactions of Cover Crop and Fertilizer Effects on Beneficial and Total Cultivable Bacteria and Fungi in an Organic Blueberry Trial, East Lansing, MI, 2008–2009

	Probability (H 0 = 0)
Effect	Num df	Den df	Fungi	Trichoderma	Streptomycetes	Bacteria	Pseudomonas	Bacillus	Soil pH
Cover crop	2	6	ns	ns	ns	0.01	ns	ns	ns
Fertilizer	2	18	<0.0001	ns	<0.001	ns	0.02	ns	ns
Year	4	18	ns	— ^z	<0.01	0.06	<0.01	ns	<0.0001 ^y
Cover crop * fertilizer	1	9	ns	ns	<0.0001	0.001	0.02	ns	0.02 ^y
Cover crop * year	2	9	<0.001	—	0.03	ns	ns	ns	0.0001 ^y
Fertilizer * year	2	9	0.02	—	<0.001	ns	0.02	ns	0.02 ^y
Cover crop * fertilizer * year	4	9	ns	—	0.005	ns	ns	ns	0.0086 ^y
Soil pH	1	9	ns	ns	<.0001	ns	<0.05	0.03
Soil pH * cover crop	2	9	ns	ns	ns	ns	ns	ns
Soil pH * fertilizer	2	9	<0.01	ns	0.0001	0.01	ns	ns
Soil pH * Year	4	9	ns	—	<0.01	ns	0.03	ns
Soil pH * cover crop * fertilizer	1	9	ns	ns	0.0001	ns	ns	ns
Soil pH * cover crop * year	2	9	<0.001	—	<0.04	<0.01	0.05	ns
Soil pH * fertilizer * year	2	9	0.02	—	<0.001	ns	0.02	ns
Soil pH * cover crop * fertilizer * year	4	9	ns	—	<0.01	0.45	ns	ns
^zNo data, only measured in 2009.
^yDenominator df = 27.

Overall, fungal populations were lower in 2008 than 2009, most likely due to decreased soil pH (Rousk et al., 2010). Fungal populations appeared to be enhanced by the protein meal-based organic fertilizer, which may have provided a more sustained food source for fungal growth relative to the synthetic fertilizer. Organic fertilizers containing amino acids and proteins tend to stimulate secondary decomposition following an immediate pulse of biological activity (Hadas and Kautsky, 1994). McGeary's 8-1-1 contains 93% of N as insoluble proteins and amino acids (http://mcgearyorganics.com/organic-fertilizer/8-1-1-side-dress-green-up.html). The compost we applied contained 25% of N in the form of soluble inorganic N (NO₃ ⁻ and NH₄ ⁺) and has been through one round of microbial processing during the composting process. Soil pH was included as a covariate to account for random field variability as main effects of nutrients and cover crops were not significant (P > 0.05). Data were square-root or natural log-transformed to satisfy distributional assumptions of ANOVA. N contained in the ammonium sulfate fertilizer is completely soluble. Thus, fertilizer effects on fungal populations in soil may reflect the ratio of insoluble organic N relative to total N.

Insect Infestation

Foliar feeding insects were not observed at a significantly higher frequency in any of the three nutrient management treatments. Blueberry leafminer and Japanese beetle abundance was variable across the planting, with some bushes having low infestation, whereas others had high levels, especially of the leafminer. Despite this, there was no significant difference among any of the treatments. Leafminer infestation was numerically higher in the compost blend treatment than the other treatments but there was no significant difference among these three treatments (F = 2.54, df = 2,33, P = 0.09) (Fig. 2). Low levels of infestation by Japanese beetles were observed at this planting, with an average of 2–3 injured leaves per bush (Fig. 2),and observations of higher leaf feeding at the edges of the planting. There was no significant difference among cover crops or among fertilization treatments in the level of Japanese beetle feeding injury (F = 0.2, df = 2,33, P = 0.82). The numerically higher number of leafminers detected on blueberries fertilized with compost blend suggests that the leafminer may do better on plants with higher leaf nitrogen levels (Fig. 2). The lack of observable differences in Japanese beetle feeding was not overly surprising given the small size of the experimental plots and that insect's extremely mobile nature.

FIGURE 2 Average (+SEM) insect damage from leafminers and Japanese beetles on plants fertilized with McGeary's organic fertilizer, compost, or conventional fertilizers at the MSU organic blueberry planting. There was no significant difference among treatments in the level of pest infestation.

OMRI Japanese Beetle Spray Trial

While there were visual differences in feeding damage among the treatments at 1 day after treatment, these differences were not significant due to high variability in the untreated controls (Table 4: F = 0.56, p = 0.73). At 4 days after treatment, there were significant differences among the treatments with both Aza-Direct treatments and the Pyganic 64 oz treatment showing significantly lower feeding damage on leaves than the untreated controls (Table 4: F = 3.38, p = 0.025).

TABLE 4 Japanese Beetle Feeding Damage to Blueberry Foliage in Laboratory Bioassays

Treatment	Rate	1 DAT	4 DAT
Untreated	NA	6.25 ± 3.61 a	3.75 ± 2.14 a
Aza-Direct	16 oz/acre	3.13 ± 1.88 a	0.75 ± 0.75 bc
Aza-Direct	32 oz/acre	0.75 ± 0.25 a	0 ± 0 c
Pyganic	32 oz/acre	2.25 ± 0.96 a	2.5 ± 0.96 ab
Pyganic	64 oz/acre	2.25 ± 0.29 a	0.5 ± 0.29 bc
Surround	25 lb/acre	0.5 ± 0.29 a	3.25 ± 2.25 ab
Foliage was collected from plants at the MSU organic blueberry planting. Percentages are presented as ±SE and percentages with the same letters within a column are not significantly different at α = 0.05.

There were no significant differences in Japanese beetle health at 1 day after treatment (F = 0.38, p = 0.86), but after 4 days, there were significant differences (F = 4.86, p < 0.01). Beetles in the Pyganic 32 oz treatment had an average health rating of 1.75 ± 0.75, which was significantly lower than the Aza-Direct 16 oz, Pyganic 64 oz, Surround, and untreated treatments (all having health ratings of 4.0 ± 0). Beetles in the Aza-Direct 32 oz treatment had an average health rating of 3.0 ± 0.71, a value that was not significantly different from any other treatments, despite the effect on feeding damage. This is highly suggestive of an antifeedant effect from this insecticide, which may have been better observed in situations without beetle enclosure on treated shoots.

Results from this trial support the grower use of Pyganic to “knock down” Japanese beetles just prior to harvest. Furthermore, Pyganic appears to kill beetles when applied at the higher rate as evidenced by a beetle health score of under 2, indicating a high level of beetle mortality. Numerically reduced feeding by Aza-Direct and Surround is also encouraging although residues from these two products have been known to temporarily remove the wax bloom after treatment (Aza-Direct) or leave white residues (Surround), making them less acceptable for growers, particularly in the fresh berry market.

CONCLUSIONS

Michigan and Great Lakes Region organic blueberry production may be at a major juncture in its development. While the 60 acres of currently certified organic plantings in Michigan make up a very small percentage (less than 0.3%) of the total Michigan acreage, the fact that this figure is poised to double within the next 3 years is encouraging. At present, it appears that most growers are likely focusing on local markets and direct sales (i.e., “you pick”) as evidenced by the relatively small size of organic plantings. However, if the organic marketplace continues to grow at its current pace, it is likely that Michigan growers will seek to penetrate the wholesale organic marketplace. However, growers will likely need better described and economically vetted organic production practices before a noticeable expansion of wholesale marketing is likely.

Nutrient and weed management are two important challenges for Great Lakes region organic blueberry growers with insect and disease management close behind. Organic nutrient management research is underway across all major United States blueberry growing regions and will continue for the foreseeable future. The development of a better understanding of how to best manipulate nutrient inputs so that high levels of ammonium and micronutrients are available during the early spring and summer but less available in the fall continues to be an important challenge for organic blueberry production. It is likely that nutrient management practices will likely vary widely for specific Michigan and Great Lakes region organic blueberry plantings depending on whether they are on native blueberry soils (acid muck or peat bog) or on acidified sands or loams. All of the mulches tested at the MSU organic blueberry planting reduced the need for hand weeding but none of them completely eliminated it. Thus, organic weed management will likely be best accomplished by combining mulch with hand weeding or burn down herbicides.

Growers also indicate a need for improved insect and pathogen management. At present, our focus has been the development of pest management tactics that replace conventional approaches. Our work with the available OMRI-approved insecticides for Japanese beetle indicate that these compounds can provide similar effects as their conventional counterparts. However, effective use of these compounds requires careful timing and application, and reapplication due to the much shorter residual control they provide. Furthermore, while this approach has yielded early success it is our hope that as Michigan organic blueberry acreage increases we will increasingly shift attention to the development of a better understanding of the population and community dynamics driving pest and disease outbreaks with the objective of the development of pest management tactics that rely less on costly off farm inputs and provide minimal system disturbance.

The current report covers the establishment phase of the MSU campus organic blueberry planting, and as such has little information on fruit-related challenges. As the planting matures we intend to continue sampling, with greater emphasis on fruit quality. Key direct pests of fruit including blueberry maggot and mummy berry will be included in this research to examine the speed of colonization of the planting by these pests.

ACKNOWLEDGMENTS

Funding for this work was provided by the North-Central SARE, State of Michigan Project GREEEN, and the Organic Farming Research Foundation. We thank Keith Mason, Steve Van Timmeren, and Noel Hahn for assistance with the insect sampling, and Sonya Plude for work with fertility and mulch treatments.