Southwest Michigan Research Articles

Relationships between intra-aggregate pore structures and distributions of Escherichia coli within soil macro-aggregates

The study evaluated the effects of soil intra-aggregate pore distributions on movement and fate of E. coli (a global indicator of fecal pollution) within soil aggregates. The first objective was to characterize pore structure of intact soil aggregates (4–6mm in size) using X-ray computed microtomography and to quantify the differences in pore structures of the aggregates from the same soil type but under >18 year contrasting land use and management settings. The studied settings were (i) conventionally plowed row crop (CT), (ii) no-till row crop (NT), and (iii) native succession vegetation (NS) treatments from Long Term Ecological Research site, W.K. Kellogg Biological Station, southwest Michigan. The second objective was to examine spatial distribution of E. coli introduced into the aggregates and the relationships between E. coli distributions and intra-aggregate pores. The results indicated that E. coli distribution in the aggregates was driven by specific configurations of the intra-aggregate pores. When the aggregates’ initial water contents were relatively low, presence of large (>100μm) pores in the aggregate interiors limited water and thus E. coli entry. Such centrally located large pores were more abundant in the aggregates from NT and NS treatments as compared to CT aggregates. Medium-sized pores (30–60μm) were more abundant in the aggregates from CT soil and such pores were relatively homogeneously distributed through entire bodies of CT aggregates. Thus, upon entering the aggregate, E. coli became more uniformly distributed through the CT aggregates, while in NT and NS aggregates it more commonly remained in the aggregate exterior parts without reaching the interiors. Implications of these distributional patterns for E. coli survival and re-entering water flow in soil under different land use need to be addressed in further studies.

Seedling light limitation does not increase across a natural productivity gradient

Aims A key idea in plant community ecology is that the identity of the limiting resource shifts from soil nutrients in low productivity sites to light in high productivity sites. This idea, and its implications for plant community structure, has been tested many times in artificial productivity gradients (fertilization studies), but whether it applies to natural productivity gradients is unclear. Methods To test whether seedling light limitation would increase across a natural productivity gradient, I conducted a cross-site field experiment in southwest Michigan, USA. At each of six old fields naturally varying in productivity, I exposed transplanted seedlings of big bluestem (Andropogon gerardii) to a light addition (tie-back) treatment that increased light availability and measured their biomass after one and two growing seasons. Important Findings Seedlings responded positively to the tie-back treatment, but positive responses did not increase across the natural productivity gradient. These results suggest that although light does limit seedling establishment, the strength of light limitation does not depend on variation in productivity in natural systems. Instead, light limitation interacted with a variety of site differences to determine establishment. Although the general principle that light limitation increases with productivity is well established, these results indicate that it may not always occur in natural systems.

Atmospheric transport of speciated mercury across southern Lake Michigan: Influence from emission sources in the Chicago/Gary urban area

Quantifying the local and regional impacts of speciated mercury (Hg) emissions from major urban and industrial areas is critical for understanding Hg transport and cycling in the environment. The Chicago/Gary urban area is one location where Hg emissions from industrial sources are significant and the regional transport of emissions may contribute to elevated ambient Hg concentrations at downwind locations. From July to November 2007, we collected semi-continuous measurements of gaseous elemental Hg (Hg0), fine particulate bound Hg (Hgp), and divalent reactive gaseous Hg (RGM) in Chicago, IL and Holland, MI to characterize the impact of Chicago/Gary source emissions on Hg concentrations in southwest Michigan and to improve our overall understanding of speciated Hg transport and deposition. The mean (and median) concentrations of Hg0, Hgp, and RGM in Chicago were 2.5ng/m3 (1.9ng/m3), 9pg/m3 (5pg/m3), and 17pg/m3 (6pg/m3), respectively. In Holland the mean (and median) concentrations were 1.3ng/m3 (1.3ng/m3), 6pg/m3 (6pg/m3), and 8pg/m3 (2pg/m3), respectively. Cluster analysis of 24-hour HYSPLIT back-trajectories associated with the semi-continuous Hg measurements indicated that southwest transport from Chicago/Gary to Holland occurred during approximately 27% of the study. In Holland, under this transport regime, we observed a five-fold increase in RGM relative to the median concentration of the other transport clusters. We applied the HYSPLIT dispersion model to two case study periods to further quantify the impact of Chicago/Gary sources on southeast Michigan and investigate the role of direct transport and dispersion of speciated Hg emissions. Results suggested that more than 50% of the maximum RGM concentrations observed in Holland during the selected periods could be attributed to direct transport of primary RGM emissions from Chicago/Gary. The remaining RGM fractions are believed to be associated with Hg0 oxidation during transport over Lake Michigan.

First Report of Root and Crown Rot of Wasabi (Wasabia japonica Matsum.) Caused by Phytophthora cryptogea in Michigan.

In September 2011, a Phytophthora sp. was isolated from wasabi (Wasabia japonica Matsum.) grown commercially in hydroponic culture in a large production facility in southwest Michigan. Approximately 20% of the plants were affected, resulting in serious losses for the grower. Plants exhibited severe wilting and root and crown rot, with soft water-soaked lesions on the crown and dark lesions on the roots. Small pieces of root tissue with dark lesions were excised and plated onto potato dextrose agar and unclarified V8 agar plates amended with 25 ppm of benomyl, 100 ppm of ampicillin, 30 ppm of rifampicin, and 100 ppm of pentachloronitrobenzene. Isolates of a Phytophthora sp. were recovered from root tissue. Isolates produced sporangia abundantly in culture. Sporangia averaged 48 μm long × 34 μm wide and were ellipsoid to ovoid, occasionally obpyriform, and were nonpapillate and noncaducous. Distinct hyphal swellings were noted and chlamydospores were observed rarely in culture. The isolate used for inoculations did not produce oospores alone in culture but was able to produce oospores when paired with an A1 culture of P. capsici and incubated in the dark. Oospores were not observed when the isolate was paired with an A2 culture of P. capsici. No growth was observed at 35°C, and the isolate was identified as Phytophthora cryptogea based on morphological and physiological traits. Pathogen identity was further confirmed using PCR primers specific to P. cryptogea (1). In addition, a BLAST search was conducted using the nucleotide database collection in GenBank comparing our isolate against Phytophthora spp., with 99% sequence similarity to P. cryptogea in two sequenced genes, beta tubulin and cytochrome c oxidase 1 (2). Sequences for the isolate were deposited in the GenBank database under accession numbers JX041520 and JX041521. To fulfill Koch's postulates, six small, potted wasabi seedlings were inoculated by placing 3 g of 1-month-old infested millet (100 g of millet, 72 ml of distilled water, 0.08 g of asparagine, and 10 7-mm diameter V8 agar plugs with actively growing P. cryptogea) onto the soil surface of each pot under coconut coir mulch. Plants were watered heavily after soil infestation and as needed thereafter. Three control plants were inoculated with sterile millet seed. The experiment was repeated once. Wilting was observed within 5 and 7 days, respectively, in the first and second experiment. All six inoculated plants were severely wilted within 25 and 56 days, respectively, except for a single plant in the second experiment that never wilted. Root and crown rot was observed on wilted plants and dark lesions could be observed on root tissue. P. cryptogea was recovered from five of the six plants inoculated in each experiment. None of the control plants in either experiment displayed symptoms of wilting, and the pathogen was not recovered from these plants when pieces of root tissue were excised and plated onto amended V8 agar. To our knowledge, this is the first report of P. cryptogea causing crown and root rot of wasabi.

Intra‐aggregate Pore Characteristics: X‐ray Computed Microtomography Analysis

Intra-aggregate pores play an important role in controlling soil processes on a micro-scale. Differences in parent materials, pedogenic processes, land use, and management practices can have a substantial effect on their characteristics. The goal of this study is to examine intra-aggregate pore characteristics using X-ray computed microtomography (μCT) images in soils of two contrasting parent materials and of contrasting land use and management. In addition, to quantify pore characteristics in aggregate exterior and interior layers we have developed an approach for aggregate boundary delineation in μCT images. Soil aggregates from a Hapludalf under Long Term Ecological Research conventional tillage treatment (LTER-CT) and native succession vegetation treatment (LTER-NS) in southwest Michigan, and from an Ustochrept under native succession vegetation and bare soil in northeast China were used. The LTER-CT aggregates had significantly greater macro- porosity (>14.6 μm in diameter) than those of LTER-NS. The LTER-NS aggregates had more large pores (>97.5 μm) and more small pores (<15 μm) than LTER-CT aggregates, while more medium size pores (37.5–97.5μm) were found in LTER-CT aggregates. Greater abundance of medium sized pores in LTER-CT aggregates could be the cause of their reported lower stability and higher macro-aggregate turnover rate. The differences in pore size distributions between LTER-CT and LTER-NS were more pronounced in the aggregate interiors, as compared to the exterior layers. In aggregates from both studied soils large pores tended to prevail in the aggregate interiors while medium size pores (37.5–97.5 μm) were more abundant in the aggregate exteriors.

Distribution and Phenology ofDasineura oxycoccana(Diptera: Cecidomyiidae) in Michigan Blueberries

The blueberry gall midge, Dasineura oxycoccana Johnson, is a serious pest of rabbiteye blueberries in Florida, Georgia, and Mississippi, and a potential pest of southern and northern highbush blueberries. Its damage has been observed with increasing frequency in highbush blueberry plantings in the Great Lakes region, including in Wisconsin and in Michigan. Unlike in rabbiteye blueberry plantings, where blueberry gall midge primarily damages flowering buds, it is found to damage only the vegetative shoots of northern highbush blueberry. In this study, farms throughout Michigan were surveyed for the presence of blueberry gall midge and it was found in 43 of 46 sampled farms in 11 counties. From 2009-2011, several monitoring techniques, including yellow sticky traps, emergence traps, observational sampling, and vegetative shoot dissections were used to determine the ecology of this species in blueberry fields in southwest Michigan. Emergence traps were most useful in early detection of blueberry gall midge in April, and observational sampling for damage symptoms and vegetative shoot dissections revealed multiple population peaks throughout July and August. Infestation was detected in vegetative shoot tips in all parts of the bushes, with initial infestation greatest at the base of bushes. Degree day accumulations until first midge detection and peak infestation suggest some potential for predicting key events in the pest's phenology. This information about the distribution and timing of infestation will be useful in developing management strategies for blueberry gall midge infestation.

Development and Evaluation of the Trauma-Informed System Change Instrument: Factorial Validity and Implications for Use

In this paper, we present the process of developing and evaluating an instrument designed to measure the extent to which a complex community system has changed as a result of a community initiative, and for purposes of this research, doing this within the content area of developing local trauma-informed child welfare systems in specific communities in Michigan. The instrument was designed for the Southwest Michigan Children’s Trauma Assessment Center’s (CTAC) Substance Abuse and Mental Health Services Administration (SAMHSA)-funded initiative to bring a trauma-informed perspective to professionals working with children in child welfare. The Trauma Informed System Change Instrument was developed with the input of experts in trauma-informed system change. Two parts of the instrument were analyzed separately using confirmatory factor analysis. A two factor model was fit for Community Characteristics and a three factor model for Individual Characteristics. Although adequate factorial validity was obtained for the instrument, specific items on the instrument that were problematic in fitting the model were identified, and suggestions for revising the instrument for improved functionality are offered, as are other potential uses of the instrument.

Cabin Fever: A Suburban Father’s Search for the Wild (review)

Reviewed by: Cabin Fever: A Suburban Father’s Search for the Wild Keith Kroll (bio) Cabin Fever: A Suburban Father’s Search for the Wild. Tom Montgomery Fate. BOSTON: BEACON PRESS, 2011. 207 PAGES, CLOTH, $24.95. A few years ago, shortly before spring break, several of my college students asked me what I was doing over the break. “I’m going on a five-day silent retreat,” I replied. “You’re doing what?!” one of my students asked. “I’m going to go to upstate New York, to engage in contemplative practice at a retreat center out in the woods. No cell phones, no computers, no texting, not even any reading. And, yep, no talking.” “No cell phones?” “No talking?” “No talking for five days?” They were incredulous. “Why would you do that?” “To practice mindfulness, to learn to pay attention, to reflect,” I said. “You’re crazy, Keith,” they half-joked. We live in a culture of distraction. Many of us (including many of my students) lead a divided life, one of imbalance, detachment, and disengagement. Maggie Jackson, author of Distracted: The Erosion of Attention and the Coming Dark Age (Prometheus, 2008) writes, “Amid the glittering promise of our new technologies and the wondrous potential of our scientific gains, we are nurturing a culture of social diffusion, intellectual fragmentation, sensory detachment. In this new world, something is amiss. And that something is attention.” Tom Montgomery Fate is keenly aware of this culture of distraction, and honestly admits it is a culture in which he too often finds himself immersed. As Montgomery Fate writes in “Picking Blackberries,” he lives “in between; [End Page 203] in between the woods and the megamall, the blue jay and the Buick, the wild and the mundane, the animal and the human.” Cabin Fever is a collection of 19 personal (and at times intimate) essays arranged according to the seasons. The collection begins in spring and recounts Montgomery Fate’s search or journey to confront this divided life and to learn to be mindful and present: in essence, to learn to pay close and careful attention to the world in which he lives. “Most of [Cabin Fever] is a humble attempt to find meaning in my own ‘travels’ on home ground, from the wilds of suburban Chicago to the woods and farms of southwest Michigan.” If this search reminds one of Henry David Thoreau’s reasons for going to the woods, it should, for it is Thoreau and Walden that serve as Montgomery Fate’s Baedekers along the way. In Walden; or, Life in the Woods, Thoreau contemplates two new technologies of his day: the railroad, which ran close to Walden Pond, and the telegraph. He is not enamored with either. “Our inventions are wont to be pretty toys, which distract our attention from serious things. They are but improved means to an unimproved end, an end which it was already but too easy to arrive at; as railroads led to Boston or New York. We are in great haste to construct a magnetic telegraph from Maine to Texas; but Maine and Texas, it may be, have nothing important to communicate.” So too in “Picking Blackberries,” the collection’s opening essay, does Montgomery Fate contemplate that very same issue, one that Maggie Jackson argues is at the heart of our distracted modern culture: technology. Montgomery Fate finds himself at his family’s small cabin, built on the farm they share with several other families, carefully observing the beauty of the blackberries that surround the cabin. The blackberries remind him of the other BlackBerry, the ubiquitous “smartphone” that controls (and organizes) many people’s lives. He is tempted to buy one, but is leery of its drawbacks. “As the technology gets smarter and faster,” he writes, “I get dumber and slower, and more distracted.” It becomes apparent to Montgomery Fate that the search to be present and pay close attention best takes place in nature, whether at the cabin (“In Plain Sight,” “Saunter,” “Cabin Fever”), on the beach at Lake Michigan (“Lake Glass”), or in his backyard in suburban Chicago watching birds with his young son (“The Gay Cardinal”). During the course of the year...

Long-term nitrate loss along an agricultural intensity gradient in the Upper Midwest USA

Nitrate (NO3−) loss from intensively farmed cropland is a long-standing, recalcitrant environmental problem that contributes to surface and groundwater pollution and coastal zone hypoxia. Here nitrate leaching losses are reported from nine replicated cropped and unmanaged ecosystems in southwest Michigan, USA. Ecosystems include four annual corn–soybean–winter wheat rotations under conventional, no-till, reduced-input, and organic/biologically-based management, two perennial cropping systems that include alfalfa and hybrid poplar trees, and three unmanaged successional communities including an early successional community analogous to a cellulosic biofuel system as well as a mature deciduous forest. The organic, alfalfa, and unmanaged systems received no synthetic, manure, or compost nitrogen. Measured nitrate concentrations were combined with modeled soil water drainage to provide estimates of nitrate lost by leaching over 11 years. Among annual crops, average nitrate losses differed significantly (p<0.05) and followed the order conventional (62.3±9.5kgNha−1yr−1)>no-till (41.3±3.0)>reduced-input (24.3±0.7)>organic (19.0±0.8) management. Among perennial and unmanaged ecosystems, nitrate loss followed the pattern alfalfa (12.8±1.8kgNha−1yr−1)=deciduous forest (11.0±4.2)≫early successional (1.1±0.4)=mid-successional (0.9±0.4)>poplar (<0.01±0.007kgNha−1yr−1) systems. Findings suggest that nitrate loss in annual row crops could be significantly mitigated by the adoption of no-till, cover crops, and greater reliance on biologically based inputs, and in biofuel systems by the production of cellulosic rather than grain-based feedstocks.

Decolonizing Archaeological Theory at Fort St. Joseph, An Eighteenth-Century Multi-Ethnic Community in the Western Great Lakes Region

Recent archaeologies of colonialism have challenged and significantly revised contemporary imaginings of Indigenous peoples' engagement with Europeans and the impacts of these entanglements on material and social realities. Changes in socio-political climate beginning in the 1970s instigated reconceptualizations that accompanied increas- ingly audible sounds of Native voices and concerns. Political action outside the discipline has heightened archaeologists' self-reflexivity and engendered new theoretical frameworks such as the shift from acculturation to agency models and the trend away from essential- ized categories towards hybridized forms. In this paper, I suggest first that the growing adoption of decolonized archaeological theory is grounded in socio-political experiences and contestation. Second, I challenge a recent reactionary critique of aboriginalism in an effort to enter the ongoing debate on the side of Indigenous archaeology to highlight some of the relationships between materiality, colonialism/ decolonialism, and archaeological theory. Finally, I show how post- colonial theoretical perspectives have influenced the archaeological interpretations of an eighteenth-century, multi-ethnic community in southwest Michigan. New ways of envisioning the past are developed through changing the relationships archaeologists establish with a broader community of stakeholders that influence the interpretations of the data that they recover.

Biomass supply from alternative cellulosic crops and crop residues: A spatially explicit bioeconomic modeling approach

Abstract This paper introduces a spatially-explicit bioeconomic model for the study of potential cellulosic biomass supply. For biomass crops to begin to replace current crops, farmers must earn more from them than from current crops. Using weather, topographic and soil data, the terrestrial ecosystem model, EPIC, dynamically simulates multiple cropping systems that vary by crop rotation, tillage, fertilization and residue removal rate. EPIC generates predicted crop yield and environmental outcomes over multiple watersheds. These EPIC results are used to parameterize a regional profit-maximization mathematical programming model that identifies profitable cropping system choices. The bioeconomic model is calibrated to 2007–09 crop production in a 9-county region of southwest Michigan. A simulation of biomass supply in response to rising biomass prices shows that cellulosic residues from corn stover and wheat straw begin to be supplied at minimum delivered biomass:corn grain price ratios of 0.15 and 0.18, respectively. At the mean corn price of $162.6/Mg ($4.13 per bushel) at commercial moisture content during 2007–2009, these ratios correspond to stover and straw prices of $24 and $29 per dry Mg. Perennial bioenergy crops begin to be supplied at price levels 2–3 times higher. Average biomass transport costs to the biorefinery plant range from $6 to $20/Mg compared to conventional crop production practices in the area, biomass supply from annual crop residues increased greenhouse gas emissions and reduced water quality through increased nutrient loss. By contrast, perennial cellulosic biomass crop production reduced greenhouse gas emissions and improved water quality.

Redox Stratification and Salinization of Three Kettle Lakes in Southwest Michigan, USA

Redox stratification, especially hypolimnetic anoxia resulting from eutrophication, and salinization resulting from application of salts for road deicing is investigated in three kettle lakes in southwest Michigan. Two of the lakes (Asylum and Woods Lakes) are located in urban Kalamazoo, Michigan, and the third (Brewster Lake) is located in rural Hastings, Michigan. In summer, the water columns of all three lakes are distinctly redox stratified, with anoxic hypolimnia and significant accumulation of reduced solutes (e.g., Mn(II), Fe(II), ammonia) in the lake bottom waters. Extremely elevated conductivity, chloride, sodium, and potassium levels are observed in the urban Asylum and Woods Lakes compared to the rural Brewster Lake, presumably due to runoff of road salt deicers applied in the surrounding watershed. These significant changes in water quality are of concern because they may detrimentally impact lake mixing, biodiversity, and ecosystem function in the urban lakes.

First Report of Blueberry Leaf Rust Caused by Thekopsora minima on Vaccinium corymbosum in Michigan.

Leaf rust symptoms have been noticed sporadically on northern highbush blueberry plants (Vaccinium corymbosum L.) in Michigan for the past 8 years. In 2009, leaf rust was seen in several cultivated blueberry fields and on greenhouse-grown blueberry plants in southwest Michigan. In 2010, leaf rust was widespread throughout western Michigan and particularly evident in the fall, sometimes resulting in premature defoliation. Cultivars Rubel, Jersey, Elliott, Liberty, and Brigitta were most commonly affected. Both the 2009 and 2010 growing seasons were characterized by above-average precipitation in early to mid-summer. Early symptoms on the adaxial leaf surface consisted of roughly circular yellow spots that later developed brown, necrotic centers. Older lesions were more angular and sometimes surrounded by a purplish border. In the fall, a "green island" effect was sometimes apparent around the lesions. On the abaxial side, numerous yellow-to-orange rust pustules (uredinia) were visible. Uredinia were dome shaped, erumpent, 100 to 400 μm in diameter, clustered, and sometimes coalescing. Urediniospores were broadly obovate with dark yellowish content and measured 19 to 25 × 16 to 20 μm (average 22 × 18 μm, n = 30). Spore walls were hyaline, echinulate, and 1.0 to 1.5 μm thick with obscure germ pores. Uredinia were examined with light and scanning electron microscopy for the presence of conspicuous ostiolar cells characteristic of Naohidemyces vaccinii (Wint.) Sato, Katsuya et Y. Hiratsuka, but none were observed. No telia or teliospores were observed. On the basis of morphology, the pathogen was identified as Thekopsora minima P. Syd. & Syd. (3,4) and a sample was deposited in the U.S. National Fungus Collection (BPI 881107). Genomic DNA was extracted from urediniospores of rust isolates from six different locations, and a 267-bp fragment of the ITS2 region was amplified and sequenced using the primers ITS3 and ITS4 (GenBank Accession No. HQ661383). All sequences were identical to each other and shared 99% identity (232 of 234 bp) with a T. minima isolate from South Africa (GenBank Accession No. GU355675). The alternate host, hemlock (mostly Tsuga canadensis L.) is a common and valuable conifer in the Michigan landscape. Hemlock trees were not examined for the presence of aecia but are assumed to play a role in the epidemiology of the disease in Michigan because leaf rust tends to be more severe near hemlock trees. Pucciniastrum vaccinii (G. Wint.) Jorst. was considered the causal agent of blueberry leaf rust until Sato et al. (1,4) identified three unique species. While T. minima has been reported on black huckleberry (Gaylussacia baccata [Wangenh.] K. Koch) in Michigan (4), to our knowledge, this is the first report of T. minima on highbush blueberry in the state. T. minima has been reported on highbush blueberry in Delaware and New York (4), Japan (2), and South Africa (3). The severity of the outbreak in 2010 warrants further research into economic losses, epidemiology, and management of the disease.

Association ofOvavesicula popilliae(Microsporida: Ovavesiculidae) With Winter Mortality of Larvae and Reduced Fecundity of Female Japanese Beetles (Coleoptera: Scarabaeidae)

Populations of Japanese beetle at sites in Michigan where Ovavesicula popilliae (Andreadis) was introduced in 1999 and 2000 were compared with nearby control sites from fall of 2005 through spring of 2008. Percent infection by O. popilliae and winter mortality of Japanese beetle were determined by sampling larvae in October and April from 12 golf holes on six courses in southeast Michigan and eight holes on four courses in southwest Michigan. Adult Japanese beetles were also collected from these golf courses in July and August of 2007 to determine the impact of O. popilliae-infection on egg development in females. In southeast Michigan, O. popilliae appeared to spread rapidly from the 100 m(2) plots where it was previously introduced to surrounding golf course holes between 2000 and 2006. However, data from southwest Michigan suggests that O. popilliae had already been introduced into the area. Regression analysis of data from all 20 golf course holes gives a significant relationship between percent infection of larvae with O. popilliae and winter mortality of Japanese beetle. Mean winter mortality of larvae around golf course holes where <10% were infected with O. popilliae was 24.7% compared with 41.7% mortality where 10-30% were infected, and 72.0% mortality where >30% were infected. Females infected with O. popilliae contained 50% fewer mature eggs than uninfected females. In addition, females from golf courses where all of the fairways and roughs were treated annually with imidacloprid contained 48% fewer mature eggs than females from golf courses where insecticides were only used on the fairways or not at all.

Genetic Analysis of Streptomycin-Resistant (SmR) Strains of Erwinia amylovora Suggests that Dissemination of Two Genotypes Is Responsible for the Current Distribution of SmR E. amylovora in Michigan

Streptomycin-resistant (Sm(R)) strains of the fire blight pathogen Erwinia amylovora were first isolated in southwest Michigan in 1991. Since that time, resistant strains have progressed northward to other apple-producing regions in the state. A total of 98.7% of Sm(R) strains isolated between 2003 and 2009 in Michigan harbored the strA-strB genes on transposon Tn5393. strA and strB encode phosphotransferase enzymes that modify streptomycin to a nonbactericidal form. Mutational resistance to streptomycin, caused by a point mutation-mediated target-site alteration of the ribosomal S12 protein, occurred in 1.3% of E. amylovora strains from Michigan. Tn5393 was originally introduced to E. amylovora on the plasmid pEa34; thus, the first Sm(R) strains isolated contained both pEa34 and the ubiquitous nonconjugative plasmid pEA29. More recently, we have observed Sm(R) strains in which Tn5393 is present on pEA29, suggesting that the transposon has moved via transposition from pEa34 to pEA29. Almost all of the strains containing Tn5393 on pEA29 had lost pEa34. Of 210 pEA29::Tn5393 plasmids examined, the transposon was inserted at either nucleotide position 1,515 or 17,527. Both of these positions were in noncoding regions of pEA29. Comparative sequencing of the housekeeping genes groEL and potentially variable sequences on pEA29 was done in an attempt to genetically distinguish Sm(R) strains from streptomycin-sensitive (Sm(S)) strains isolated in Michigan. Only 1 nucleotide difference within the total 2,660 bp sequenced from each strain was observed in 2 of 29 strains; multiple sequence differences were observed between the Michigan strains and E. amylovora control strains isolated in the western United States or from Rubus spp. Alterations in virulence observable using an immature pear fruit assay were detected in three of eight Sm(R) strains examined. Our current genetic data indicate that only two Sm(R) strain genotypes (strains containing pEA29::Tn5393 with Tn5393 inserted at either nucleotide position 1,515 or 17,527 on the plasmid) are responsible for the dissemination of Tn5393-encoded streptomycin resistance in Michigan, and that the Sm(R) and Sm(S) strains in Michigan compose a homogenous group.

Seasonal pattern of oviposition by the North American grape berry moth (Lepidoptera: Tortricidae)

The seasonal patterns of oviposition by the North American grape berry moth, Paralobesia viteana (Clemens) (Lepidoptera: Tortricidae) were monitored in juice grape (Vitis labrusca) vineyards in southwest Michigan. Egg deposition was recorded throughout the growing season at two vineyards in 2006, and at four vineyards from 2007 to 2009. In each vineyard, a random sample of 100 grape clusters was visually inspected twice-weekly and the number of newly laid eggs was counted. We found that oviposition was continuous but variable throughout the season. Egg deposition started in early June coinciding with early grape bloom, continued at low level until mid- to late July, intensified in August close to veraison, and ended in September often before harvest. There were no consistent periods without oviposition that would indicate distinct generations. To determine the contribution of moth immigration into the vineyard to the pattern of oviposition, six grape plants located at the edge of a vineyard next to woods were covered with field cages and stocked with infested fruit. Oviposition and berry infestation were followed weekly on covered and exposed plants. Although higher numbers of eggs and infested berries were found on fruit of exposed vines than enclosed vines, egg deposition and berry infestation followed the same pattern in both treatments. This result indicates that the seasonal pattern of egg deposition is not dependent on immigration of grape berry moth of wild grape origin. The pattern of oviposition by grape berry moth described here contributes to the difficulty of controlling this pest using conventional insecticides with short residual activity.

Food or Fuel: Rising Gasoline Prices and Food Access Among WIC Families in Non-Metropolitan Southwest Michigan

In 2007 and early 2008 retail gasoline prices rose nearly 75% along with rising food prices. We investigated grocery shopping attitudes and behavior of 69 families receiving Women, Infants and Children (WIC) nutrition program benefits in non-metropolitan southwest Michigan and 8 local food retailers during this period. Interviews covered food buying habits and the impact of rising gasoline prices. Analysis revealed heightened concern about household food budgets, decreased shopping frequency, compromised food quality (fewer fresh foods), and, in several cases, likely food insufficiency. Retailers confirmed customer concerns and changes in shopping habits. Findings suggest that food insecurity risk among this population may increase when gasoline prices rapidly rise.

Nonlinear hierarchical models for predicting cover crop biomass using Normalized Difference Vegetation Index

Incorporating cover crops into agricultural systems can improve soil structural properties, increase nutrient availability, reduce erosion and loss of agrochemicals, and suppress weeds. These benefits are a function of the amount of cover crop biomass that enters the soil. The ability to easily and inexpensively quantify the spatial variability of cover crop biomass is needed to better understand and predict its potential as an input to agricultural systems. Here, we explore the use of Normalized Difference Vegetation Index (NDVI) as a source of information for improving accuracy and precision of cover crop biomass prediction. We focus on developing models that account for biomass variability within and among fields. These models are used to produce digital data layers of predicted biomass and associated uncertainty. We propose hierarchical nonlinear models with field random effects and a residual variance function to accommodate strong heteroscedasticity. These models are motivated using aboveground biomass of red clover ( Trifolium pratense L.) measured on three different dates in five fields in southwest Michigan. Model adequacy was assessed using the Deviance Information Criterion. Given this criterion, the “best” fitting model included field effects and a polynomial function to account for non-constant residual variance. Importantly, we demonstrate that accounting for heteroscedasticity in the model fitting is critical for capturing uncertainty in subsequent biomass prediction.

Management intensity – not biodiversity – the driver of ecosystem services in a long-term row crop experiment

A positive role for biodiversity is assumed for managed ecosystems. We conducted a 12-year study of this sustainability principle, through separate manipulation of management intensity and crop diversity. The site was located in southwest Michigan, representative of rain-fed production, with high climate variability and well-drained soils. Provisioning services of grain and protein yield were monitored, simultaneous with supporting services of soil fertility, C and N, and regulating services associated with water quality (N-use efficiency and nitrate-N leached in gravimetric lysimeters). Surprisingly, a strong role for management was shown, and almost nil for crop diversity. Organic management (ORG) sustained soil fertility, augmented soil C (36% increase), enhanced N retention (50% decrease in nitrate-N leaching) and improved N-use efficiency, compared to conventional, integrated (INT) management. Provisioning of grain – quantity, quality and temporal yield stability – was highest in INT continuous maize (monoculture and biculture) with an annual yield of 6.4 Mg ha −1, compared to ORG of 5.1 Mg ha −1. Biodiverse rotational systems (three and six species) produced 25% lower yield, but the grain was of high quality. A focus on ORG management rather than crop diversity is suggested as a means to sequester C, and produced grain in a semi-closed system.

Are brighter eggs better? Egg color and parental investment by House Wrens

ABSTRACT Recent work suggests that avian egg color could be a sexually selected signal to males that provides information about female condition, female genetic quality, or maternal investment in eggs. Theory predicts that egg color should influence male investment if it is an honest signal of the marginal fitness returns on paternal investment; a male should invest more in a colorful clutch if that investment increases offspring success more than an equivalent investment in a less colorful clutch. Some experimental support for this hypothesis has been found for species that lay blue eggs containing the pigment biliverdin, a potentially costly antioxidant. However, the brown eggshell pigment protoporphyrin, a pro-oxidant associated with poor female condition, has received less attention as a potential predictor of female quality or investment. We performed a cross-fostering experiment with House Wrens (Troglodytes aedon) in southwest Michigan in 2007 to test whether brown egg color was related to female condition or maternal investment, and whether male provisioning of nestlings was related to egg color. We swapped entire clutches between nests and measured egg characteristics and parental provisioning rates. We found that brighter eggs (i.e., those with less brown pigment) were heavier, and that nestlings that hatched from brighter eggs were fed at higher rates by their foster mothers, but not by their foster fathers. This pattern is consistent with the hypothesis that egg color is a potential signal of egg quality and female investment, but we found no evidence of a male response to this potential signal. This lack of a response could be the result of methodological limitations, a nonadaptive biological constraint, or adaptive indifference because chicks from brighter eggs do not actually yield increasing marginal returns on paternal investment. Clearly, additional study is needed to differentiate among these possibilities. Un trabajo reciente sugiere que el color de los huevos pudiera ser una señal sexual que provee a los machos información sobre la condición de la hembra, la calidad genética de ésta o la inversión maternal en los huevos. La teoría predice que el color de los huevos debe influenciar en la inversión del macho si es una señal honesta de ganancia marginal de aptitud en la inversión parental; un macho debiera invertir más en una camada colorida si esta inversión aumenta el éxito de los hijos que una inversión equivalente en una camada menos colorida. La evidencia experimental, para esta hipótesis, ha sido encontrada para especies que ponen huevos azules los cuales contienen el pigmento biliverdina, que es un antioxidante potencialmente costoso. Sin embargo, el pigmento pardo en el cascarón, protoporfirina, un pro-oxidante asociado a una condición pobre de la hembra, ha recibido menos atención, como vaticinador potencial de la calidad de la hembra o de su inversión. En el 2007, realizamos un experimento de adopción cruzada en Reyezuelos (Troglodytes aedon) en el sureste de Michigan para poner a pruebas si los huevos pardos estaban relacionados a la condición de la hembra o a la inversión maternal, o si la atención (alimentación) de los machos a los pichones estaba relacionada al color de los huevos. Intercambiamos camadas entre nidos y medimos las características de los huevos y la taza de cuidado parental. Encontramos que los huevos más brillantes (ej. aquellos con menos pigmento pardo) eran más pesados, y que los pichones que nacían de estos huevos, eran más alimentados por sus madres nodrizas pero no así por sus padres adoptivos. Este patrón es consistente con la hipótesis de que el color de los huevos es una señal prospectiva o potencial de la calidad de los huevos e inversión maternal. Sin embargo, no encontramos evidencia, de esta señal potencial, en la respuesta de parte de los machos. Esta falta de respuesta pudiera ser el resultado de una limitación en la metodología utilizada, una limitación biológica no-adaptativa, o una indiferencia adaptativa, porque los pichones de huevos más brillantes no ofrecen un aumento de rendimiento marginal en la inversión parental. Claramente, se necesitan estudios adicionales para diferenciar entre estas posibilidades.