Cherry Orchards Research Articles

Pre-Plant Soil Treatments Influence Tree Performance and Nematode Dynamics in Replanted Cherry Orchards.

In this two-year field study, the impacts of pre-plant soil management strategies, including soil fumigation, nematicide application, and organic amendments, on the growth and nematode community dynamics on cherry cultivars 'Emperor Francis' and 'Ulster' grafted to 'Mahaleb' rootstock were investigated in a replanted orchard site. In the first year, fumigation with 1,3-dichloropropene - chloropicrin mixture (Telone C-35) led to significantly increased trunk cross-sectional area and canopy height in both cultivars. Pratylenchus penetrans population densities were suppressed only short-term. Plots treated with the fungicide/nematicide fluopyram (Velum® Prime) had P. penetrans reproduction factors below one throughout both years independent of the scion. Additionally, the combined application of Seed Starter 101®, Dairy Doo® compost, and straw mulch reduced the reproduction factor of P. penetrans to below one in the first year. In the same time period, this combinatory treatment had the highest reproduction factor for bacterivore and fungivore nematodes. Based on results of this study, fumigation with Telone® C-35 resulted in improvement of tree establishment and provided effective short-term suppression of P. penetrans. Velum® Prime exhibited longer-term efficacy for the suppression of P. penetrans.

Organic matter mitigates biotic impact of copper in fruit orchard soil

Inorganic copper (Cu) fungicides and bactericides are widely used to control disease in fruit and vegetable crops and has led to widespread accumulation of the metal in soil beyond regulatory thresholds. We aimed to elucidate the impacts of Cu on soil health within cherry orchard soils in New Zealand, focusing on three biological indicators: earthworm behaviour, soil respiration, and plant growth. We sampled soils from four blocks of different ages within a single orchard, varying in amounts of accumulated soil Cu (7 - 263 mg kg-1) but also in Soil Organic Matter (SOM) content (3 - 10 %). Experimental work was designed to isolate the impacts of both Cu and SOM on three critical biological descriptors: earthworm behaviour, soil respiration and root growth. Soils were amended to standardise both variables in laboratory and glasshouse experiments. The results demonstrated a pronounced inhibition of soil respiration and root development, as well as adverse effects on earthworm behaviour, with increasing Cu concentrations. SOM played a mitigating role, reducing the bioavailability and toxicity of Cu to soil organisms. However, the buffering capacity of SOM is limited and long-term reliance on SOM to mitigate Cu toxicity is not sustainable. Currently Cu continues to accumulate in most orchard soils. This study highlights the importance of assessing Cu bioavailability and soil health in the context of orchard management.

Effects of Successive Top-Dressing Application of Lime on a Sweet Cherry Orchard in Southern Chile

Annual top-dressing application of agricultural lime is a common practice in fruit orchards on acidic soils in southern Chile, which could result in surface over-liming and base imbalances. A trial was performed in a cherry orchard with an 8-year history of surface liming to evaluate the effectiveness of lime materials in neutralizing acidity in the soil profile and the effect on the tree nutritional status. No-lime (NL), calcitic (AgL), hydrated (HL), and liquid (LL) lime treatments were applied on soil surface at commercial rates, and soil acidity variables were measured at depths of 0–5, 5–10, and 10–20 cm in samples collected at 0, 15, 30, 60, and 225 days after application. Tree nutritional status was evaluated through foliar analysis. Top-dressing application of AgL was ineffective in ameliorating subsoil acidity at depths >5 cm, even in high-rainfall conditions. HL did not exhibit greater alkalinity mobility compared to AgL, although it had a faster but shorter-lived reaction. At the manufacturer-recommended rates, LL application was ineffective. After 8 years of top-dressing liming with AgL, a significant stratification of soil pH, Al, and Ca was observed. However, foliar concentration of bases did not reflect the surface Ca accumulation in soil, discarding an antagonistic cation competition for tree uptake.

Unoccupied-Aerial-Systems-Based Biophysical Analysis of Montmorency Cherry Orchards: A Comparative Study

With the global population on the rise and arable land diminishing, the need for sustainable and precision agriculture has become increasingly important. This study explores the application of unoccupied aerial systems (UAS) in precision agriculture, specifically focusing on Montmorency cherry orchards in Payson, Utah. Despite the widespread use of UAS for various crops, there is a notable gap in research concerning cherry orchards, which present unique challenges due to their physical structure. UAS data were gathered using an RTK-enabled DJI Mavic 3M, equipped with both RGB and multispectral cameras, to capture high-resolution imagery. This research investigates two primary applications of UAS in cherry orchards: tree height mapping and crop health assessment. We also evaluate the accuracy of tree height measurements derived from three UAS data processing software packages: Pix4D, Drone2Map, and DroneDeploy. Our results indicated that DroneDeploy provided the closest relationship to ground truth data with an R2 of 0.61 and an RMSE of 31.83 cm, while Pix4D showed the lowest accuracy. Furthermore, we examined the efficacy of RGB-based vegetation indices in predicting leaf area index (LAI), a key indicator of crop health, in the absence of more expensive multispectral sensors. Twelve RGB-based indices were tested for their correlation with LAI, with the IKAW index showing the strongest correlation (R = 0.36). However, the overall explanatory power of these indices was limited, with an R2 of 0.135 in the best-fitting model. Despite the promising results for tree height estimation, the correlation between RGB-based indices and LAI was underwhelming, suggesting the need for further research.

Deciduous fruit trees and grapevines as alternative crops in Demathophora necatrix (syn. Rosellinia necatrix) infested soils

White root rot, caused by Dematophora necatrix (syn. Rosellinia necatrix), affects deciduous trees. A D. necatrix infection-distribution survey found widespread disease in apple and cherry orchards in northern Israel bordering a Mediterranean forest, although the forest trees were unaffected. Because cherry and apple orchards must be abandoned due to long fungal survival in infested soils, alternative deciduous fruit trees and grapevines were assessed for growth in these D. necatrix-infested orchards. In the field, grapevine rootstocks and the almond–peach rootstock GF-677 were most tolerant to D. necatrix-infested soil. Apple was the most sensitive crop, with the rootstock Hashabi being more tolerant than PI80 or MM104. The Mediterranean forest tree Pistacia atlantica, which can serve as a rootstock for pistachio, was as sensitive as kiwifruit and apple, and persimmon rootstock sensitivity was not different from grapevine. Those results show that beside the above mentioned crops, vineyards can also replace apple orchards in D. necatrix-infested soils and so broadens the list of possible crops for the local farmers in a Mediterranean climate at altitudes above 440 m above sea level. This has also been observed in a commercial 10-year-old vineyard of ‘Shiraz’ grapevines grafted on SO4 rootstock. The almond-peach rootstock GF-677 can also be grown in infested soil, but in commercial orchards requires additional treatment for adequate disease control.

Wildflower strips in polytunnel cherry orchard alleyways support pest regulation services but do not counteract edge effects on pollination services

Wildflower strips in polytunnel cherry orchard alleyways support pest regulation services but do not counteract edge effects on pollination services

Influence of Fruit Load Regulation on Harvest and Postharvest Fruit Quality and Antioxidant-Related Parameters in Sweet Cherry (Prunus avium L.) cv. Regina Cultivated under Plastic Covers in Southern Chile.

Plastic covers have been used to prevent environmental constraints negatively affecting sweet cherry production in Southern Chile. However, less information is available on agronomic practices and their effects on fruit quality in sweet cherry covered orchards. Thus, in this study, we evaluated the impact of fruit load regulation on cherries' antioxidant-related parameters and the quality and condition at harvest and postharvest in sweet cherry (Prunus avium) cv. Regina that was cultivated under a plastic cover in Southern Chile. For this, four fruit load treatments were manually applied-(i) 100% fruit load (the control), (ii) 80% fruit load, (iii) 60% fruit load, and (iv) 40% fruit load-in a commercial sweet cherry orchard for two seasons (2021/2022 and 2022/2023). The results revealed that the yield and fruit load were not significantly different between the treatments. Interestingly, the 60% and 40% fruit loads increased the fresh weight, fruit size, and firmness (20.3%) compared to the control (the 100% fruit load) during both seasons. Likewise, the 60% and 40% fruit load treatments exhibited the highest fruit size distribution of 30 mm, while the 100 and 80% fruit load treatments showed the highest fruit distribution with fruit sizes between 28 mm and 24 mm. The total soluble solids (TSSs) did not vary among the fruit load treatments, while a significant increase was found in the titratable acidity (TA) in the 60 and 40% fruit load treatments during both seasons. No significant differences in antioxidant activity (AA) and total phenols (TPHs) among the treatments were observed during both seasons. Overall, the results revealed that the fruit load treatments, mainly 40%, increased the fruit weight and firmness and reduced pitting in fruits by 39.4% at postharvest. Thus, fruit thinning might be an important agronomical practice to regulate fruit load, positively affecting fruit quality at harvest and during postharvest storage in sweet cherry cv. Regina cultivated under a plastic cover. However, more biochemical and molecular studies are needed to elucidate the mechanism involved in this improvement.

First Report of Pseudomonas amygdali pv. morsprunorum causing Bacterial Canker in Sweet Cherry Orchards in Washington State.

In 2023, an outbreak of bacterial canker disease (BCD) in sweet cherry orchards caused significant economic losses to growers and nurseries in the Pacific Northwest, USA (Fig. S1). The cherry industry in Washington State alone is valued at over $800 million (USDA NASS, 2022). BCD poses a recurring threat to the state's sweet cherry [Prunus avium (L.) L.] orchards, especially young and newly planted orchards. Three Pseudomonas species, including P. syringae pv. syringae (Pss), P. amygdali pv. morsprunorum (Pam) (formerly P. syringae pv. morsprunorum Race 1, Psm1), and P. avellanae pv. morsprunorum (formerly P. syringae pv. morsprunorum Race 2, Psm2), have been reported to be associated with BCD in sweet cherries (Hulin et al. 2019). While Pss is widely prevalent in the United States, Pam has only been reported in Michigan (Renick et al., 2008) as well as in Europe, Central America, South Africa and Australia (Hulin et al. 2019) . In 2023, we surveyed more than 60 cherry orchards and collected hundreds of canker samples from newly planted up to 8-year-old trees. BCD prevalence ranged from 40-100% in cherry orchards, leading to the removal of hundreds of thousands of trees. Affected cherry trees exhibited characteristic bacterial canker symptoms, including dead bud, canker, and gummosis (Fig. S1). Bacteria were isolated from canker tissues or ooze on King's B (KB) agar plates (King et al., 1954) and more than 300 fluorescent Pseudomonas isolates were obtained from 12 symptomatic sweet cherry cultivars. PCR results using Pss- and Pam- specific primers (SyrB and Psm1, Table S1) (Sorensen et al., 1998; Kałużna et al., 2016) revealed that 91.9% and 8% isolates were tested positive for SyrB and Psm1, indicating that these isolates potentially belong to Pss and Pam, respectively. Pathogenicity tests using immature cherries cv. Sentina showed that all isolates caused typical necrotic lesions and could be re-isolated and re-identified as Pss and Pam, thus completing Koch's postulates. The identity of three Pam representative isolates (S79, S158, S202) was further confirmed by comparing gyrD and rpoD housekeeping genes as well as 16S rRNA gene sequence with other Pam strains in GenBank (Parkinson et al., 2010; Gomila et al., 2017). Blast searches against GenBank using gyrB (GenBank accession numbers PP357444-PP357446), rpoD (PP357447-PP357449) and 16S rRNA (GenBank accession numbers PP421223-PP421225) gene sequences, ranging from 520 to 859bp, matched those of the Pam isolates (GenBank accession numbers CP026558 or PP218075) with 100% homology and 100% query coverage, further indicating that these isolates are indeed Pam. This represents the first documented record of Pam causing BCD in the Pacific Northwest, USA, suggesting the complexity of the disease, which underscores the need for effective management strategies for cherry growers in the region.

Assessment of non-target toxicity of insecticides on Ganaspis brasiliensis (Ihering) in laboratory and field conditions.

G1 strain Ganaspis brasiliensis (Ihering) has been recently released in both Europe and America as a biological control agent of the spotted wing drosophila, Drosophila suzukii (Matsumura). In initial phases of classical biological control programs, it becomes imperative to evaluate the susceptibility of parasitoids to insecticides, to identify the best alternatives to adopt in an integrated pest management and organic perspective. In this study, we evaluated lethal and sublethal effects of topical application of five different insecticides classes: neonicotinoids, diamides, pyrethroids, organophosphates and spinosyns. Additionally, we tested residual toxicity in field trials in vineyards and sweet cherry orchards. Adult wasps' susceptibility to different insecticides' classes were consistent between laboratory and field. Spinosad exhibited the highest toxicity, with a median lethal concentration (LC50) of 0.00372 of the maximum field dose, and the highest knock-down effect in field trials, causing 92.5 ± 5% of mortality at T0. λ-cyhalothrin showed sublethal effects on both male and female insects' longevity when applied at LC30. In field trials, deltamethrin showed the highest persistence, causing significant parasitoid mortality up to 14 days after treatment. Conversely, cyantraniliprole was the least toxic active ingredient according to both topical and residual bioassays, even though its residues caused mortality up to 7 days after the treatment in the field. Our results indicate that spinosad and λ-cyhalothrin are highly toxic to G. brasiliensis, making them incompatible with classical biological control programs. Cyantraniliprole exhibited lower toxicity, and may be considered a selective pesticide for the integrated management of D. suzukii. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Osmia lignaria (Hymenoptera: Megachilidae) increase pollination of Washington sweet cherry and pear crops.

Apis mellifera Linnaeus (Hymenoptera: Apis), honey bees, are the most widely used managed crop pollinators. However, their high rental cost and uncertain availability for North American orchard crops have motivated growers to explore alternative pollination options. We examined whether adding solitary, spring-flying Osmia lignaria Say (Hymenoptera: Megachilidae), blue orchard bees, as co-pollinators with A. mellifera in Washington sweet cherry and pear orchards enhances fruit set and yield compared to the use of A. mellifera alone. We added managed O. lignaria to orchard sites where A. mellifera hives were already present. Fruit set, fruit yield, and O. lignaria reproduction at O. lignaria-supplemented sites were compared to nearby, paired sites pollinated only by A. mellifera (3 paired cherry and 3 paired pear sites). For both crops, the addition of O. lignaria significantly increased fruit set but did not yield at harvest. Microscopic inspection of pollen grains from O. lignaria nest cell provisions confirmed that O. lignaria primarily visited orchard flowers. Mean retention of O. lignaria in cherry orchards was slightly higher (65%) than O. lignaria retention reported in other orchard crops (30%-60%). However, retention in pear orchards was much lower (≤20%). These results show that supplementing hives with O. lignaria in Washington spring orchard crops can increase overall pollination, but that trees fail to bear developing fruit to maturity. The strategy of using co-pollinators, O. lignaria and A. mellifera, in US orchards may act as "pollination insurance" when A. mellifera hives are in low supply or when the weather is not amenable for A. mellifera flight during the bloom period.

Determining the Main Infection Courts in Sweet Cherry Trees of the Canker Pathogens Calosphaeria pulchella, Cytospora sorbicola, and Eutypa lata.

The major fungal canker pathogens causing branch dieback of sweet cherry trees in California include Calosphaeria pulchella, Cytospora sorbicola, and Eutypa lata. These pathogens have long been known to infect cherry trees mainly through pruning wounds. However, recent field observations revealed numerous shoots and fruiting spurs exhibiting dieback symptoms with no apparent pruning wounds or mechanical injuries. Accordingly, this study was conducted to assess the incidence of the three pathogens in symptomatic terminal shoots and dying fruiting spurs, in addition to the wood below pruning wounds in branches. Surveys were conducted in five sweet cherry orchards across three counties in California. We also investigated the possibility that leaf scars, bud scars, and wounds resulting from fruit picking could serve as infection courts for Cal. pulchella, Cyt. sorbicola, and E. lata by means of artificial inoculations in the field. Orchard surveys revealed that Cal. pulchella had the highest pathogen incidence below pruning wounds in branch samples, followed by Cyt. sorbicola and E. lata. Among terminal shoots with dieback symptoms and dying fruiting spurs, Cyt. sorbicola was the most prevalent, followed by Cal. pulchella. Results from field inoculations indicated that fruit-picking wounds could serve as important infection courts for Cal. pulchella, Cyt. sorbicola, and E. lata, with average pathogen recovery of 41.5, 63, and 36.2%, respectively. Results also indicated that leaf and bud scars could serve as an entry site for Cyt. sorbicola, although recovery was relatively low. The present study is the first to identify harvest-induced wounds on fruiting spurs of sweet cherry as an important infection court of Cal. pulchella, Cyt. sorbicola, and E. lata.

Assessing the relationship between soil variability, canopy density, and yield in Utah tart cherry orchards

Assessing the relationship between soil variability, canopy density, and yield in Utah tart cherry orchards

Evapotranspiration and water stress assessment in a sweet cherry orchard using in-situ and remote sensing techniques

Evapotranspiration and water stress assessment in a sweet cherry orchard using in-situ and remote sensing techniques

Phytocoenotic assessment of herbaceous plant communities in the organic sweet cherry orchard

Biodiversity loss is one on global environmental issues facing humanity. Intensive use of natural resources has led to degradation of landscapes and reduction of the species diversity of plant communities. Therefore, finding natural solutions to overcome these challenges is an urgent issue. The purpose of the study was to investigate the dynamics of floral composition and coenotic structure of herbaceous plant communities in an organic cherry orchard for the sustainable functioning of the agricultural landscape. The dynamics of the coenotic composition of natural grasses of vegetation cover in the organic cherry orchard was studied during 2013-2020 in the arid conditions of the Southern Steppe of Ukraine on low-humus sandy loam soils. Morphological, ecological, and geographical methods were used to investigate the species diversity of flora in an organic garden. The composition of herbaceous plant communities was estimated using conbentional geobotanic description methods. The results of the study of the species composition and coenotic structure of plant communities of grass cover in an organic sweet cherry orchard are presented. Grassing of the garden with natural grasses has led to the enrichment of agricultural landscapes with useful species that are important components of sustainable agricultural systems and can perform ecological services. Colonisation of the grass cover by invasive and quarantine species was not observed due to natural processes of demutation succession and the use of moderate four-fold mowing of plants during the growing season (to a height of 15- 20 cm). As part of herbal plant communities in the 8th year of research, all species were useful, had medicinal properties, and served as a food base. The natural grasses in an organic sweet cherry orchard are a resource of biomass and biodiversity. Phytocoenotic analysis of the grass cover in the organic cherry orchard will allow substantiating and proposing principles for predicting the development of plant communities to optimise their structure, improve quality, and maintain biodiversity

Tree performances of eight rootstocks grafted with ‘Šumadinka’ sour cherry

Aim of study: This study was conducted to determine the suitability of seven clonal and one seedling rootstocks for grafting of sour cherry cv. ‘Šumadinka’ trough early tree growth, precocity, productivity and fruit quality. Aim of study: To evaluate the suitability of seven clonal rootstocks and one seedling rootstocks for grafting the sour cherry cv. ‘Šumadinka’ based on early tree development, precocity, productivity and fruit quality. Area of study: A sour cherry orchard in village Prislonica, Serbia, near Čačak city. Material and methods: The sour cherry cultivar ‘Šumadinka’ was grafted onto Colt, MaxMa 14, Krymsk 6, Adara, Cigančica, Gisela 5, Gisela 6 and Myrobalan rootstocks. Standard and validated procedures were used to measure tree growth, productivity (from 2017 to 2020), leaf area, fruit physical properties and fruit chemical composition (from 2019 to 2020). Main results: Significant differences were observed among rootstocks in leaf and petiole dimensions, leaf area, tree vigour, yield, fruit size, soluble solids content, titratable acidity, sugars and vitamin C contents, ripening and sweetness indexes. Trees grafted on Adara exhibited the highest tree vigour, while those on Gisela 6 produced the largest fruit size. On the other hand, Colt trees generally displayed the highest sugar content and sweetness index. Adara also showed improvements in fruit quality characteristics, whereas the properties associated with Myrobalan received the lowest evaluation scores. Research highlights: Adara rootstock demonstrated good adaptability to heavy and acidic soil conditions in Serbia, even though it was originally selected for cherry cultivation in heavy, waterlogged, and calcareous soils in Spain. This adaptability likely contributed to its higher vigour, yield, yield efficiency and good fruit quality.

Seasonal population fluctuation and life history in different temperatures of Myzus cerasi (Hemiptera: Aphididae) on cherry trees: a field and laboratory study.

This study determined the seasonal population fluctuation of Myzus cerasi (Fabricius) (Hemiptera: Aphididae) in cherry orchards and the effect of different temperatures on the life-history parameters of these aphids under laboratory conditions. Our field results showed that the population fluctuations and densities of M. cerasi on cherry trees were positively affected by the temperature increase between seasons. Also, our laboratory results showed that M. cerasi survived and reproduced at all temperatures tested under laboratory conditions. Female longevity was observed as 19.00 ± 2.38, 18.72 ± 0.49, and 12.59 ± 0.74 days, and fecundity was 10.14 ± 2.26, 9.36 ± 0.59, and 7.27 ± 0.84 offspring/female at 20, 25, and 30 °C, respectively. Although the highest net reproductive rate (R0) was observed numerically at 25 °C (7.80 offspring/female), there was no significant difference compared to 20 °C (7.10 offspring/female). The highest intrinsic rate of increase (r) and the highest finite rate of increase (λ) were calculated at 30 °C (0.15 ± 0.01 and 1.16 ± 0.01 day-1, respectively), and there was no significant difference compared to 25 °C. The mean generation time (T) of M. cerasi showed a significant difference at all temperatures tested and decreased from 22.59 ± 0.33 days at 20 °C to 12.78 ± 0.37 days at 30 °C. Consequently, our results revealed that the seasonal population fluctuation and the life history of M. cerasi in the field and laboratory conditions were affected significantly by different temperatures. Our data obtained in the field and the laboratory will contribute to the understanding of M. cerasi biology and to the management of the pest.

Quantifying the impact of crop coverings on honey bee orientation and foraging in sweet cherry orchards using RFID

AbstractAdvancements in agricultural production have seen the rapid adoption of protected cropping systems globally. Such systems have been optimized for plant growth and efficiency, with little understanding of the potential impacts to key insect pollinators. Here, we investigate the effect of bird netting and polythene rain covers on the health and performance of honey bees (Apis mellifera L.) during the pollination of sweet cherry crops. Over two consecutive seasons, 12 full‐strength colonies were equipped with tagged bees and radio frequency identification (RFID) systems. The colonies were equally divided between open control, bird netted and polythene (semi‐permanent VOEN in 2019 and retractable Cravo in 2020) groups. Over 1300 individual bees were monitored for the duration of the commercial pollination period to determine behavioural parameters such as foraging commencement age, number and duration of trips and overall survival. Bees began foraging within the optimum age range (mean 15.7–24.1 days) under all covering types, with little indication of prolonged stress or increased mortality during the short season. Polythene covers (VOEN & Cravo) were found to significantly increase the total time needed for bees to orientate successfully. Once orientated, bees placed under covers conducted up to 155% more foraging trips, with a longer cumulative duration. Covering type was found to significantly impact the amount and type of pollen collected, with the most restrictive system (VOEN) yielding the highest proportion of cherry pollen. Overall, we found little evidence to suggest that the tested protective covers have a detrimental impact to honey bee foraging in cherry crops.

Bacterial root cancer of cherry in the conditions of the Western part of Azerbaijan

Bacterial root cancer or goiter of the root system is a plant disease with symptoms of proliferation of plant stem or root tissues, caused by the transfer of Ti-plasmids from the virulent bacterium Agrobacterium tumefaciens Conn. into plant cells. The article presents the results of studies of bacterial root cancer of cherries in the conditions of the Ganja-Kazakh geographical zone during 2021—2023. In these years of research, it was found that the disease is widespread in cherry orchards in the western part of the country and severely damages trees. The causative agent of the disease from the soil through wounds and cracks in different parts of the root system penetrates into its cells and the incubation period of the disease begins. It lasts (depending on temperature) 4—7 weeks. The resulting cancer growths do not lead to the rapid death of cherry trees. However, the pathogen suppresses their overall growth, viability and reduces their resistance to fungal and other infections, which leads to a significant decrease in yield, and after a while the energy of the plants is depleted, they gradually dry out and eventually die. The bacterium Agrobacterium tumefaciens Conn. has been studied in detail in the laboratory over the years of research. We have developed a system of complex agrotechnical methods for combating bacterial root cancer.

Effect of Aged Cherry Orchard Soil on the Potted Seedling Growth of Malus hupehensis (Pamp.) Rehd

Due to the aging of trees, aged apple and cherry orchards need to be rebuilt urgently. However, due to the limitation of land resources, it is inevitable to rebuild the apple orchard by taking the aged cherry orchard as a replacement, which will lead to replant disease and seriously affect the sustainable development of the horticulture industry. This study investigated the effect of aged cherry orchard soil on the growth of M. hupehensis seedlings grown in pots, and it was further verified that allelochemicals in soil were one of the reasons for this effect. Three treatments were implemented: aged apple orchard soil (ppl), aged cherry orchard soil (pyl), and aged cherry orchard soil after fumigation with methyl bromide (pyz). Compared with pyz, pyl treatment significantly decreased the biomass, root growth, and antioxidant enzyme activity of M. hupehensis seedlings, and increased the content of MDA. Compared with ppl, pyl contains a smaller number of fungi and bacteria, but the abundance of the four disease-causing Fusarium remained high. In addition, the levels of allelochemicals found in the soil of aged cherry orchards can inhibit the normal growth and development of M. hupehensis seedlings. Amygdalin most strongly inhibited these seedlings. In summary, directly planting M. hupehensis seedlings in the soil of the aged cherry orchards still inhibits their normal growth and development, although the seedlings grow better than in aged apple orchard soil. Therefore, it is not feasible to directly plant M. hupehensis seedlings in the soil of aged cherry orchards, and measures should be taken to eliminate allelochemicals such as amygdalin and harmful microorganisms.

Plant virus diversity in bee and pollen samples from apple (Malus domestica) and sweet cherry (Prunus avium) agroecosystems.

Honey bee (Apis mellifera) pollination is widely used in tree fruit production systems to improve fruit set and yield. Many plant viruses can be associated with pollen or transmitted through pollination, and can be detected through bee pollination activities. Honey bees visit multiple plants and flowers in one foraging trip, essentially sampling small amounts of pollen from a wide area. Here we report metagenomics-based area-wide monitoring of plant viruses in cherry (Prunus avium) and apple (Malus domestica) orchards in Creston Valley, British Columbia, Canada, through bee-mediated pollen sampling. Plant viruses were identified in total RNA extracted from bee and pollen samples, and compared with profiles from double stranded RNA extracted from leaf and flower tissues. CVA, PDV, PNRSV, and PVF coat protein nucleotide sequences were aligned and compared for phylogenetic analysis. A wide array of plant viruses were identified in both systems, with cherry virus A (CVA), prune dwarf virus (PDV), prunus necrotic ringspot virus (PNRSV), and prunus virus F (PVF) most commonly detected. Citrus concave gum associated virus and apple stem grooving virus were only identified in samples collected during apple bloom, demonstrating changing viral profiles from the same site over time. Different profiles of viruses were identified in bee and pollen samples compared to leaf and flower samples reflective of pollen transmission affinity of individual viruses. Phylogenetic and pairwise analysis of the coat protein regions of the four most commonly detected viruses showed unique patterns of nucleotide sequence diversity, which could have implications in their evolution and management approaches. Coat protein sequences of CVA and PVF were broadly diverse with multiple distinct phylogroups identified, while PNRSV and PDV were more conserved. The pollen virome in fruit production systems is incredibly diverse, with CVA, PDV, PNRSV, and PVF widely prevalent in this region. Bee-mediated monitoring in agricultural systems is a powerful approach to study viral diversity and can be used to guide more targeted management approaches.