Societal Impact Statement More than 100 edible native berries grow across Canada's vast territory and are used by over 600 Indigenous Peoples of Canada as a main component of their diet. This research provides critical insights into the ecology, phenology, and cultivation of black huckleberry ( Vaccinium membranaceum ), a species of significant ecological and cultural importance in western North America. This work not only supports biodiversity and ecosystem health but also bolsters Indigenous food sovereignty and cultural heritage. The findings offer practical guidelines for policymakers, conservationists, and Indigenous communities, fostering collaborative efforts to preserve this vital species in the face of climate change and environmental challenges. Summary Conserving native food‐plant species is crucial amid anthropogenic ecosystem disturbances and climate change. In western North America, native Vaccinium spp. (western huckleberries) are vital for sustenance and medicine, historically linking Indigenous communities and European settlers. This review, inspired by Westbank First Nation, synthesizes current knowledge and identifies research gaps concerning the distribution, growth, reproduction, abiotic and biotic stresses, and propagation of V. membranaceum or st̓łqiłəml̓x in Nsyilxcen (black huckleberry), emphasizing its ecological and cultural significance. The distribution and growth of V. membranaceum are shaped by abiotic factors (climate, soil, and fire) and biotic interactions (mutualisms with mycorrhizal fungi, pest and disease pressures). Understanding of how those factors individually and collectively (e.g. through phenology) influence V. membranaceum habitat suitability and berry yield will enhance understanding of the potential for its resilience. Furthermore, the integration of traditional and in vitro propagation techniques offers promising avenues for cultivation and conservation. By highlighting the dynamics shaping V. membranaceum populations, the review emphasizes the need for multidisciplinary research to safeguard this species. Bridging indigenous and contemporary scientific knowledge systems can foster sustainable management practices, ensuring the prosperity of V. membranaceum and the communities and ecosystems dependent on it.

Phaeomoniella chlamydospora (Pch) is reported as one of the main pathogens responsible for Petri disease in young grapevines, causing internal necrosis and eventual grapevine death within the first few years after planting. Phaeomoniella chlamydospora is highly prevalent in nursery material, and it can be found in vascular tissues of both asymptomatic and symptomatic grapevines. Accordingly, it has been hypothesized that Pch may act as a latent pathogen. It is thought that abiotic and/or biotic stress factors could influence its transition from an endophytic to a pathogenic phase. Plant-parasitic nematodes are commonly found in vineyard soils, and they are a common biotic stress factor in grapevines. The objective of this research was to determine whether stress caused by the ring nematode (Mesocriconema xenoplax) contributes to Petri disease development. Dormant Merlot canes were vacuum inoculated with 10µL suspension containing either 1,000, 5,000, or 25,000 Pch conidia, rooted, and planted in soil containing ring nematodes in a two-year greenhouse and a three-year field experiment. Commercial arbuscular mycorrhizal (AM) fungi were inoculated into greenhouse pots to investigate whether AM fungi minimize stress, resulting in reduced Petri disease development. Phaeomoniella chlamydospora abundance before and after treatment was determined using droplet digital™ PCR. At the end of the experiment, Pch abundance was positively correlated with initial inoculum level. In both greenhouse and field experiments, black necrosis of vascular tissues was positively correlated with initial Pch abundance, while brown necrosis was positively correlated in the field, but negatively correlated in the greenhouse. In the greenhouse, Pch abundance was greater in ring nematode and AM inoculated grapevine soil than in nematode-free, AM inoculated treatments, but AM treatment itself had no effect. In the field, mortality was higher in grapevines inoculated with 5,000 Pch spores and planted in ring nematode infested soil than in nematode-free soil. This study showed that ring nematode infestation and AM colonization of the roots increase Pch growth in young Merlot grapevines and that a combination of ring nematode infestation and Pch infection increase grapevine susceptibility to winter kill.

Compost application has many benefits for soil fertility and grapevine performance. Composts introduce new nutrient sources and exogenous microorganisms that enhance soil nutritional status and diversify microbial populations. This can lead to pathogen suppression by beneficial soil microbes through a variety of different mechanisms. Grapevine crown gall (GCG), induced by Allorhizobium vitis, has detrimental impacts on grapevine performance and crop quality. Plant-parasitic nematodes may increase the frequency and/or severity of soil-borne A. vitis infections because they induce wounds on roots through which the bacterium can easily enter the vine and establish systemic infection. Compost prepared from organic materials has reduced pathogenic nematode populations in soil of other perennial crop plants. Therefore, we hypothesized that organic compost application would improve soil fertility parameters, plant performance, crop quality, yield, and reduce the severity of A. vitis infection via reduction in pathogenic nematode soil populations. Three organic waste composts were applied in-row in a Chardonnay (Vitis vinifera) vineyard infected with A. vitis and plant-parasitic nematodes. After three years, all composts increased total carbon and nitrogen (%), organic matter (%), and phosphorus (mg.kg–1 soil) content in soil. Compost containing peat moss decreased Paratylenchus population densities in soil, while vineyard waste compost only reduced Ximphinema population densities in one year. However, no meaningful changes in plant performance, crop quality, yield, or GCG severity were detected. Extreme winter and summer temperatures experienced during this study likely reduced grapevine performance overall and potentially decreased the impact of improved soil fertility and lower parasitic nematode populations on GCG disease.

Phaeomoniella chlamydospora (Pch) is one of the main pathogens causing Petri disease, a grapevine trunk disease responsible for the decline and mortality of grapevines within a few years after planting. Phaeomoniella chlamydospora has been shown to be prevalent in asymptomatic grapevine nursery material, leading to the hypothesis that it may act as a latent pathogen, transitioning from an endophytic to a pathogenic phase under grapevine stress. To investigate this hypothesis, a two-year greenhouse and a four-year field experiment were conducted on young self-rooted ‘Merlot’, and ‘Merlot’ grafted onto ‘SO4’ rootstock, artificially inoculated with different spore concentrations of Pch and subjected to water stress. Additionally, the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis was inoculated in the soil in the greenhouse experiment to investigate its effects on abiotic stress mitigation and thus, disease development in water stressed and non-stressed grapevines. DNA was extracted from the grapevine wood, and Droplet Digital™ PCR was conducted to determine Pch abundance before and after the experiments. In the greenhouse, Pch abundance in inoculated grapevines was greater in water stressed grapevines treated with AM than in stressed grapevines without AM or in non-stressed grapevines. Basal necrosis was greater in grapevines inoculated with Pch. In the field, Pch abundance was not affected by water stress, but basal necrosis was greater in grapevines inoculated with a high spore concentration of the fungus. Symptoms resembling Petri disease developed in the third year of the field experiment, where water stress increased grapevine mortality. This study shows that water stress may increase Pch abundance and mortality in young grapevines within the first few years after planting.

Mesocriconema xenoplax and Pratylenchus penetrans are important plant parasitic nematodes of cherry trees, but little is known of how soil and water management practices affect the buildup of either species in cherry orchards. A split-plot field experiment was initiated in 2014 to compare five soil treatments (untreated control, preplant fumigated, compost, bark chip mulch, compost+bark chip mulch) under drip and microsprinkler irrigation. Plant-parasitic nematode populations were monitored through 2023. The population of M. xenoplax was initially detected in only 3% of the 60 plots whereas P. penetrans was initially present in all plots. By 2023, M. xenoplax were detected in 70% of plots with maximum population density among plots of 834 M. xenoplax 100 cm-1 soil. Mesocriconema xenoplax became more abundant in compost plots and fumigated plots than in untreated plots, and more abundant under drip than microsprinkler irrigation. In contrast, P. penetrans were least abundant in compost plots and less abundant under drip than microsprinkler irrigation. The opposing responses of these two nematode species illustrate tradeoffs in pest pressures that can occur with changes in orchard soil and water management practices, obscuring effects of either species on tree growth.

The ring nematode, Mesocriconema xenoplax, has become recognized as a widespread pest of sweet cherry trees in the Okanagan Valley of British Columbia (BC). Understanding the cumulative impacts of M. xenoplax on tree health, interpreting diagnostic sample data, and predicting the impacts of climate change on M. xenoplax population densities all depend on knowledge of the temporal dynamics of M. xenoplax populations and their linkage with soil temperature and moisture regimes. The objective of this study was to measure population densities of M. xenoplax on a monthly basis over five years, in relation to soil temperature and moisture regimes, in a 16-year-old irrigated sweet cherry orchard. We tested the following hypotheses: (i) population densities would start low each spring and increase continuously with soil degree-day heat accumulation during each growing season, and (ii) year-to-year variation in population growth during the growing season would be correlated with year-to-year variation in soil degree-day heat accumulation. The data did not support these hypotheses and indicated that although there were significant differences in population densities among sample dates, there were no regular seasonal cycles of population growth and decline. We suggest that in mature cherry orchards, density-dependent processes mask the influences of annual changes in soil temperature and moisture on population processes. The data indicate that for diagnostic sampling purposes, all seasons would be equally representative of M. xenoplax population densities in irrigated orchards in BC. Furthermore, the lack of any strong linkage between soil temperature regimes and within- or across-year population dynamics indicate that modeling efforts based solely on abiotic drivers of temperature and moisture would not likely represent changes in population dynamics of M. xenoplax that will actually occur with climate change.

While cover crops (CC) are known to enhance soil health, outcomes are often subtle and confined to a shallow surface soil layer. We assessed 15 soil health indicators over three CC trials with a 15-species Blend polyculture, a Mustard biculture {white [Sinapsis alba L.] and brown [Brassica juncea (L.) Czern.] mustards}, Buckwheat (Fagopyrum esculentum Moench), and Faba bean (Vicia faba L.) monocultures, and a Weedy fallow (no CC, weeds allowed to grow) on an organic farm in southern Alberta. Soil sampling times included (i) summer pre-termination; (ii) fall post-termination; and (iii) spring post-termination of CC. Twelve of 15 soil health indicators showed significant effects of CC treatment for at least one sampling time. Soil organic C (SOC) ranked highest with 80% of sampling times showing significant CC effects. N-related indicators [total N (TN), nitrate-N)] were also quite sensitive, being significantly affected by CC treatment at 60% of sampling times. Three soil health indicators [acid phosphomonoesterase (AcP), wet aggregate stability, and free-living nematodes (FLN)] were consistent in their non-responses to CC treatment at all sampling times. Comparing CC treatments with a Weedy fallow, showed that not all enhancements of soil health were explained by inclusion of a CC, with Weedy fallow as effective for some indicators. A polyculture Blend significantly enhanced soil health over a monoculture CC or Weedy fallow in 46% of instances of soil health indicator improvement. While CC led to enhancement of soil health, results were not always consistent, being contingent on specific indicators.

Plant-parasitic nematode populations were analyzed from composite soil samples collected from 62 vineyard blocks throughout Nova Scotia in 2018 and 2019. Nematode groups of potential concern that were found included ring nematodes (family Criconematidae), dagger nematodes (Xiphinema spp.), and root-knot nematodes (Meloidogyne spp.). Ring nematodes were overall the most widespread and abundant group of plant-parasitic nematodes, recovered from 79% of blocks with an overall average population density of 114 nematodes per 100 cm3 soil. Ring nematodes tended to be more abundant in older blocks. DNA sequence analyses of a subset of the ring nematode populations confirmed the presence of Mesocriconema xenoplax, which is the species known to be damaging to and most widely associated with grapevine globally. The analyses indicated that Criconema permistum was also present, notably in samples with the greatest ring nematode population densities. The results indicate that ring nematodes could be affecting the health of Nova Scotia vineyards, particularly in the future as populations continue to develop in relatively young vineyards and as older blocks are replanted. Additional research is needed to delineate the distribution of M. xenoplax vis-a-vis other species and to experimentally assess the host-parasite relationship between C. permistum and grapevine.

A greenhouse pot study was conducted on four cover crops (annual ryegrass, perennial tetraploid ryegrass, winter wheat cv. 'Caledonia' and sorghum-sudangrass) and one rotation crop (sweet corn cv. 'Sheba') to compare the efficiency of these crop species as hosts of Paratrichodorus minor (Colbran) Siddiqi, and the ability of the nematodes to acquire tobacco rattle virus (TRV) from roots of infected plants and re-transmit it to healthy plants. P. minor reproduced rapidly on sorghum-sudangrass and sweet corn and re-transmitted the virus to indicator plants. Annual ryegrass, perennial ryegrass, and winter wheat cv. 'Caledonia', all of which re-transmitted TRV poorly in the greenhouse, were evaluated in two years of field studies for fall establishment and soil coverage, nutrient sequestration, effect on parasitic nematode populations and on subsequent potato crops. Annual ryegrass performed best overall in terms of establishment, ground cover, overwintering survival and foliar biomass production. None of the cover crops had a consistently significant effect on populations of parasitic nematodes in field plots, including Pratylenchus, Paratrichodorus, and Meloidogyne. Both ryegrass cover crops appeared to provide a favourable environment for survival of root knot nematodes (Meloidogyne spp.), although they are not considered to be hosts of this nematode. There was no difference in soil carbon, nitrogen or potato yield following any cover crop. Symptoms of corky ringspot were not observed in the field and TRV was not detected in potato plants by RT-PCR.

Pratylenchus penetrans is one of the most important plant-parasitic nematodes causing losses in economically significant crops such as apple, cherry, corn, grapes, oat, onion, peach, potato, soybean, strawberry, and wheat. The objective of this study was to isolate and characterize plant growth promoting rhizobacterial (PGPR) strains from sweet cherry rhizospheres with biocontrol potential against P. penetrans, and to evaluate the antagonistic activity of the selected strains on a model plant (onion), in a growth chamber experiment. Five strains: three actinomycetes (Streptomyces fulvissimus A12, S. venezuelae A30, and S. annulatus A34) and two pseudomonads (Pseudomonas sp. P3 and P. donghuensis P17) with nematicidal activity were isolated. The selected PGPR strains decreased P. penetrans populations on onion roots and enhanced onion root length and dry weight. Among possible mechanisms of action, the strains displayed the capacity to produce nematicidal lytic enzymes such as chitinases and proteases, and form biofilms, which is an advantage in colonizing the plant rhizosphere. Some of them also showed antifungal activity against the phytopathogenic fungi Fusarium oxysporum C1-1, Ilyonectria macrodidyma C1-1, and Ilyonectria spp. C2-1 isolated from roots of cherry trees affected by replant disease. The multifunctionality of the strains, and the fact that they were isolated from the cherry rhizosphere, makes them good candidates to be used as biocontrol agents in sweet cherry orchards affected by P. penetrans.

Fruit production in the Okanagan Valley of British Columbia is dominated by apple, sweet cherry, and wine grape. The relative importance of sweet cherry and grape has increased in recent decades, but little was known of the plant-parasitic nematodes associated with those crops. Soil samples analyzed for plant-parasitic nematodes were collected from a total of 39 apple orchards, 61 cherry orchards, and 57 vineyards; most were collected in 2018, but 36 cherry orchards were sampled in 2012. Soil properties were also assessed and related to nematode population densities. Nematode genera of potential significance were, in order of prevalence, Pratylenchus, Mesocriconema, Xiphinema, Paratylenchus, Paratrichodorus, Hemicycliophora, and Meloidogyne. Pratylenchus were found in 79, 98, and 81% of the apple, cherry, and grape plantings, respectively; Mesocriconema were found in 51, 79, and 82%; and Xiphinema were found in 59, 51, and 77%. Population densities of the three dominant genera were influenced more by soil texture than any other soil characteristics, with Pratylenchus being negatively correlated with percentage clay, Mesocriconema positively correlated with percentage sand, and Xiphinema positively correlated with percentage silt. The high prevalence of Mesocriconema in cherry orchards and vineyards in this region is significant because Mesocriconema is known to be an important pest of other Prunus crop species and grapevines in other regions. This study therefore provides a rationale for increasing grower awareness and research efforts on the impacts and management of Mesocriconema and other plant-parasitic nematodes in orchards and vineyards in the region.

Grapevine trunk diseases (GTDs) are major biotic factors reducing yields and limiting vineyard economic life spans. Fungi in the GTD complex cause a range of symptoms in host plants, although these pathogens are slow wood colonizers and potentially latent pathogens. Understanding has recently increased on the possible roles that GTD fungi may play as latent pathogens, and how this can be translated into disease management. This paper summarizes evidence for the latent nature of infections by these fungi in grapevines and other hosts. Abiotic and biotic stressors have been associated with symptom expression in many hosts, but limited information is available regarding their roles in symptom development in grapevines. Based on research conducted in other pathosystems, this review discusses how abiotic and/or biotic stress factors may influence the transition from the endophytic to the pathogenic phases for GTD fungi. Potential methods for stress mitigation are also outlined as alternative GTD control strategies to minimize the economic impacts that that these diseases have on grape production.

Increasing the carbon (C) content of agricultural soils can help mitigate rising atmospheric CO2 concentrations, improve soil health and increase crop yield. Unlike annual cropping systems, soils planted to perennial woody crops, such as vineyards and orchards, are left undisturbed for many years making them particularly amenable to soil C storage. Here, we used a regional sampling campaign of over 80 commercially-managed sites across the Okanagan Valley, in the southern interior of British Columbia, Canada, to examine the spatial distribution of soil C under irrigated perennial woody crops. Using this living lab approach, we collected soils from the crop and drive rows of apple and cherry orchards, and vineyards subjected to a wide range of real-life management regimes (e.g., for weed and pest control, fertilizer application, etc.). Sites were selected with soils belonging to five surficial deposit classes, representing 40% of the mapped agricultural land area. Soil C was spatially heterogeneous across all the sites, with the surface soil (0-15 cm) of drive rows containing more C than the soil in adjacent crop rows. Clear differences emerged among cropping systems, despite the variation in management practices applied by individual growers. Drip-irrigated apple orchards showed the greatest spatial heterogeneity, with C concentrations of 2.9% in the drive row and 1.8% in the crop row, while vineyard and cherry orchard soils showed the least, with differences between crop and drive rows of approximately 0.3%. Higher C concentrations in the drive rows appeared to be the result of recently assimilated/less processed litter and fine root C inputs from the shallow-rooted understory vegetation. This was confirmed using stable isotope analysis: drive row soil C was significantly C-13 depleted compared to the crop row soil, to a depth of 30 cm. Overall, cherry orchards contained the most C (70 Mg C ha(-1) to a depth of 30 cm), vineyards the least (48 Mg C ha(-1)), and apple orchards were intermediate (66 Mg C ha(-1)). A recent land-use survey in 2015 determined that 8501 ha of agricultural land in the Okanagan Valley was planted to apples, cherries or grapes, and that large shifts in crop land area have occurred since the previous survey, conducted in 2006. We estimate that apple orchards currently hold approximately 199 Gg C, vineyards 188 Gg C and cherry orchards 110 Gg C. Marked differences in soil C storage between the cropping systems, despite the fact some were less than 10 years old, suggests that soils in this region are responsive to changes in crop and associated management practices over relatively short time periods. We conclude that the drive rows of vineyards offer the greatest scope for increased soil C storage among woody perennial horticultural cropping systems in the Okanagan Valley but that 'long-term' soil carbon storage may not be possible in these soils.

Abstract The Okanagan Valley of British Columbia hosts a wine grape industry that has grown substantially in the past three decades in terms of both acreage and economic benefit to the region. The ring nematode, Mesocriconema xenoplax, has recently been found to be widespread in vineyard soils in the region. This study used field microplots to assess the potential impacts of a local population of M. xenoplax on the first four years growth of either self-rooted ‘Merlot’ or ‘Merlot’ vines grafted onto three commonly used rootstocks: 3309C, 44-53M, and Riparia Gloire. The population of M. xenoplax multiplied to comparable levels on self-rooted vines and all rootstocks, indicating that none of the vine genotypes were resistant to M. xenoplax. Inoculation with M. xenoplax reduced cumulative pruning weights of self-rooted vines by 58%. Inoculation with M. xenoplax reduced trunk cross-sectional areas of 3309C by 45% and that of self-rooted vines by 38%, whereas it did not affect trunk cross-sectional areas of 44-53 or Riparia Gloire, indicating differing levels of rootstock tolerance to M. xenoplax. Our data suggest that M. xenoplax is likely impacting vineyard health and productivity in the region, and the selection of rootstocks and management practices to minimize impacts of this nematode should be considered in future vineyard replant management programs.

Abstract High NO3 concentrations in the Abbotsford‐Sumas aquifer are linked to raspberry (Rubus idaeus L.) production. Passive capillary wick samplers were used to quantify the impacts of N, irrigation, and alley managements on drainage and NO3 leaching from raspberry rows and alleys over 4 yr. Conventional management (100 kg N ha−1 surface broadcast on the row as a split application, clean cultivation of alleys, and fixed‐duration drip irrigation) was compared with different mineral fertilizer N rates, N applied as manure, alleys seeded to a perennial forage grass or an autumn‐seeded spring barley (Hordeum vulgare L.) crop, or evapotranspiration (ET)‐scheduled irrigation. The temporal pattern of drainage and NO3 leaching was driven by seasonal precipitation and growing season irrigation. Growing season drainage and NO3 leaching were much lower under ET‐scheduled irrigation compared with fixed irrigation. Nitrate leaching was high (up to 90 kg N ha−1), even with no managed N inputs due to high inherent soil fertility and large quantities of N applied in irrigation water. Nitrate leaching was insensitive to N fertilizer rate. Application of N as poultry manure more than doubled NO3 leaching compared with fertilizer, emphasizing the need to use organic N inputs judiciously. The perennial grass alley cover crop resulted in the greatest overall reduction in NO3 leaching. Our data indicate that no single management strategy is sufficient to protect groundwater quality. Rather, an integrated package of improved practices (i.e., application of a reduced rate of mineral N through fertigation, combined with ET‐scheduled irrigation and perennial alley crop) is necessary to protect groundwater quality.

This study examined the effects of nitrogen fertilization on populations of Rotylenchus robustus, Pratylenchus crenatus, and Paratrichodorus renifer, and indices of free-living nematode community structure, in relation to highbush blueberry production in British Columbia, Canada. The field experiment was established in fall of 2008 with six replicate plots of each of four experimental N fertilization treatments: 0, 100, 150, and 200% of the annual application rate recommended for conventional blueberry production in the region. Nematode populations were quantified annually from 2009 through 2015, and then nematode populations and root biomass were quantified at seven sample dates from 2016 through 2019. Population densities of R. robustus were consistently greater in the 100% treatment than in the 0, 150, and 200% treatments which did not differ from each other. Population densities of P. crenatus were consistently greater in the 150% treatment than in the 0, 100%, and 200% treatments. The nematode structure index and two indices of diversity declined monotonically with N fertilizer rate, indicating broader changes in the soil food web that could have had indirect, feedback effects on population dynamics of the plant-parasitic nematodes.