Asparagus Fields Research Articles

CAN THE RETURN TO THE NATURAL CONDITIONS OF IN VIVO PARASITIZATION INCREASE THE INFECTIVITY PERFORMANCE OF EPNS?

Experiments are in progress in Apulian asparagus fields for the control of Parahypopta caestrum (Hübner) (Lepidoptera, Cossidae) with microbial control agents (MCAs), mainly entomopathogenic nematodes and fungi.Different bioassays were carried out in laboratory and field conditions to prove the efficacy of native and commercial strains of the EPNs Steinernema feltiae (Filipijev), S. carpocapsae (Rhabditida, Steinernematidae) and Heterorhanditis bacteriophora Poinar (Rhabditida, Heterorhabditidae), and EPF Beauveria bassiana (Bals.-Criv.) Vuill. (Hypocreales, Cordycipitaceae). Among the field experiments, one was planned with the release of Galleria mellonella (L.) (Lepidoptera, Pyralidae) cadavers previously infected with native strains of EPN Steinernema feltiae and the comparison was carried out with a commercial strain of the same nematode species. Key Words: Parahypopta caestrum, Beauveria, Heterorhanditis, Steinernem

Applications of Saponin Extract from Asparagus Roots as Functional Ingredient.

When replanting an asparagus field, the roots of the previous crop are crushed and incorporated into the soil, creating problems of autotoxicity and fungal infections. Asparagus roots can be considered as a valuable byproduct, since they are very rich in saponins (3-6%), compounds currently considered as bio-emulsifiers. The objective is to evaluate the emulsifying and foaming capacity of a saponin extract from asparagus roots (ARS) and compare it with other commercial extracts. ARS was obtained using a process patented by our research group. The results have shown that ARS has activity similar to Quillaja extract. Its critical micellar concentration falls between that of Quillaja and Tribulus extracts (0.064, 0.043, and 0.094 g/100 mL, respectively). Both emulsifying and foaming activities are affected by pH, salt, and sucrose to a similar extent as the other extracts. Additionally, it has demonstrated an inhibitory effect on pancreatic lipase, which is even better than the other two studied extracts, as indicated by its IC50 value (0.7887, 1.6366, and 2.0107 mg/mL for asparagus, Quillaja, and Tribulus, respectively). These results suggest that ARS could serve as a natural emulsifying/foaming agent for healthier and safer food products and as a potential aid in treatments for obesity and hyperlipidemia.

Ökoszisztéma-szolgáltatások javítása terménydiverzifikációval a Kiskunsági-homokháton – különös tekintettel a szélerózió elkerülésére

The destructive environmental impacts of large-scale agriculture are further aggravated by drier climate in the Danube-Tisza sand region, where soil fertility is low, water retention is very limited and groundwater levels are steadily dropping. The prevention of wind erosion is a central task in raising the level of ecosystem services. Among other related services the enrichment of the blown-sand soil with organic matter (enhancing carbon sequestration), the improvement of soil structure and water retention capacity and achieving higher soil biodiversity are major objectives. The international Diverfarming project (2017–2022) within the EU Horizon 2020 Program focussed on the impacts of crop diversification and low-input practices. In the experiments intercropping with different annual crops was investigated and its influences on some provisioning and regulating ecosystem services were evaluated in an asparagus field in Jakabszállás. Although the findings point out the decisive role of soil moisture conditions, the positive impacts of diversification are also remarkable. The local farmer agrees that crop diversification improves soil quality, but he denies that it would directly influence farm competitiveness, which is primarily dependent on the costs of fertilization, plant protection and labour. Further analyses are needed to prove the benefits of diversification through enriching soil microbial life and the possible reduction of fertilizer use while water demand is kept at a low level and the same crop quality is ensured.

Effect of Organic and Mineral Soil Additives on Asparagus Growth and Productivity in Replant Soils

The repeated cultivation of asparagus in the same field can severely reduce yield. A complex of predominantly microbial causes is suspected. Limited plant development, establishment problems, and yield loss may occur, particularly in light sandy soils. In order to address this replant problem and evaluate alternative cultivation conditions, two asparagus fields were treated with different supplements and were cultivated for 5 years to investigate their impact on yield. The results from the pot trials using soils from these fields are presented, along with the field trial findings. The trials included the incorporation of mushroom substrate (champost), Fimonit (clay mineral), mustard meal (biofumigation), and Micosat F Uno (including arbuscular mycorrhizal fungi, Trichoderma viride, and rhizosphere bacteria species). In the pot trials, the sterilised soil exhibited a growth benefit over the original soil. However, the tested additives had no significant effects in the short period of 8 weeks. At one of the tested field sites, the marketable asparagus yields following champost, Fimonit, biofumigation, and Micosat treatments were 14, 6, 16 and 12% higher than that of the control soil, respectively, but no significant differences in treatment effect were observed in the second test field. Biofumigation using mustard meal and champost was most successful in reducing the impact of replanting on yields.

Post-harvesting late summer-autumn weed vegetation in small size arable fields in Veneto: new insights into root crop communities in North East Italy

Abstract A research was conducted in the Veneto region (NE-Italy) inside kitchen gardens and potato fields of outer pre-Alps, and in asparagus fields on the low Po plain near the Adriatic coast, in late summer-autumn after harvesting. Original vegetation-plot records were compared with historic and recent materials from Italy, especially N-Italy, and with comparable associations from Central and South-Eastern Europe, to ensure a consistent syntaxonomical frame of this highly dynamic vegetation. At the same time it was possible to shed light on the actual occurrence of past coenoses, cited by Italian authors for the Po plain. The analysis not only confirmed the occurrence of Echinochloo-Setarietum pumilae in north-eastern Italian territories, but also showed that it was more extensive than previously thought. It also confirmed the persistence of Panico-Polygonetum persicariae. The historical presence of Veronico-Lamietum hybridi occurring in pre-Alps and Dolomites needs confirmation. Further regional-scale investigations of summer crop weed vegetation appear necessary.

Non-host habitat at local and landscape scales promotes overwintering success of a specialist insect pest

Incorporating non-crop habitats around cropping fields is often promoted to enhance biodiversity and deter crop pests. However, few studies have investigated how these habitats influence the overwintering success of pest populations. In this study, we investigate how a specialist insect pest, the asparagus beetle (Crioceris asparagi, Coleoptera: Chrysomelidae), uses local and landscape resources for overwintering. We surveyed beetles in 2019–2020 at 11 asparagus farms in Michigan, USA, and conducted experiments to compare overwintering survival of adult beetles in five substrates commonly found in asparagus agroecosystems. We compared the overwintering number of beetles across three habitat types: asparagus field, weedy margin, and woodlot. Overwintering asparagus beetle abundance was highest within sites with deciduous leaves and decomposing asparagus stalks. We found a negative relationship between the abundance of dead trees in adjacent woodlots and adult beetle abundance. We then expanded beyond the woodlots with a landscape analysis conducted at multiple spatial scales. Landscape analysis indicated that deciduous forest within 1250 m of sites increased beetle abundance in focal asparagus fields, while asparagus production at spatial scales greater than 1500 m suppressed their populations. Our findings indicate that certain specialist pests, like asparagus beetles, depend on host resources for overwintering, but non-host habitat from the surrounding landscape is also important to their success. Practically, removal of host and non-host debris (leaf litter) from asparagus fields may lead to decreased survival and lower pest pressures. In addition, crop-dominated landscapes may not require in-field habitat management of overwintering substrates to the same extent as more diverse landscapes with higher proportions of non-host habitat (deciduous forest). Ultimately, we argue that the net positive and negative impact of increasing non-host habitat at the landscape level should be considered when developing integrated pest management strategies for specialists at the local scale.

Soil Nitrous Oxide Emission and Methane Exchange From Diversified Cropping Systems in Pannonian Region

Diversified farming systems are promoted to improve ecosystem services in agriculture while maintaining productivity. Intercropping could improve soil quality, the stability of yields and climate resilience. Whether direct emissions of greenhouse gases from soil are reduced as well, depends on the specific measures of diversification. Here, we determined the greenhouse gas emissions from soils of two diversification experiments in the Pannonian climate of Hungary. Firstly, in an asparagus field, oat and field pea was introduced as intercrop between the asparagus berms. Secondly, grass and aromatic herbs were intercropped in a vineyard between the grape rows. The results show that especially for nitrous oxide, average treatment emissions can increase with additional legumes (+252% with intercropped field peas) but decrease with aromatic herbs (−66%). No significant changes were found for methane exchange. This shows that, while other ecosystem services can be increased by intercropping, changes in soil greenhouse gas emissions by intercropping are highly context dependent.

Routine On-farm Soil Tillage Helps Control Asparagus Fly (Plioreocepta Poeciloptera)

Asparagus fly (Plioreocepta poeciloptera (Schrank, 1776)) is a serious pest in German asparagus (Asparagus officinalis L.) production. To evaluate the effects of different routine on-farm soil tillage measures on the number of flies emerging the following spring, asparagus fields in Lower Saxony, Germany, were investigated. Soil samples were taken before and after tillage in autumn 2017 and autumn 2018. Investigations were also conducted in both years on the effect that the soil depth at which asparagus fly pupae were buried had on the emergence of adult flies.This study revealed that the number of emerging flies was not reduced by mulching, but was significantly reduced by subsequent tillage and/or tillage and dam formation. The emergence rate of adult flies was significantly reduced the deeper the pupae had been buried the previous autumn. The effects also depended on the year. The highest mean emergence rate observed was 68% and 45% for pupae buried at a depth of 10 cm and 20 cm, respectively. In conclusion, the key mechanism causing a decrease in asparagus fly population the following spring through routine on-farm tillage could be the burial of pupae when forming dams. Routine on-farm soil tillage can be regarded as a physical measure for controlling asparagus fly and is therefore an essential tool in the integrated pest management of asparagus production.

Geographical Origin Does Not Modulate Pathogenicity or Response to Climatic Variables of Fusarium oxysporum Associated with Vascular Wilt on Asparagus.

Asparagus crop is distributed worldwide, covering very different climatic regions. Among the different diseases that affect asparagus, vascular Fusarium wilt, caused by Fusarium oxysporum f. sp. aparagi (Foa), stands out. It is not only the cause of large economic losses due to a decrease in yield and shortened longevity of the plantation, but also prevents replanting. This work aimed to determine if F. oxysporum isolates associated with vascular wilt on asparagus have adapted differentially to the different agro-environmental conditions. The potential correlation between origin and mycelial growth under different temperatures and humidity conditions was analysed for isolates from asparagus fields cultivated in northern and southern Europe. The genetic and pathogenic variability were also analysed. While a clear effect of water activity on mycelial growth was observed, all isolates responded in a similar way to changes in water activity in the medium, regardless of their geographical origin. The results revealed a low genetic variability of F. oxysporum isolates associated with vascular wilt on asparagus without signs of differentiation correlated to geographical origin. The southernmost isolates of the two cultivated varieties inoculated did not express more pathogenicity than those isolated from the colder region.

The Effects of Different Fertilization Practices in Combination with the Use of PGPR on the Sugar and Amino Acid Content of Asparagus officinalis

The present study examined the effects of different nitrogen (NH4NO3) and potassium (KNO3) fertilization levels in combination with a nitrogen-fixing, plant growth-promoting rhizobacteria (PGPR) inoculation on the carbohydrate (CHO), amino acid content, and nutrient concentrations (N, P, K) in the spears and the root system of asparagus plants. No significant differences were indicated between the different fertilization treatments regarding N, P, and K in the leaves and roots of asparagus. The inoculation of the asparagus fields with PGPR, no matter the type of the inorganic fertilizer, resulted in increased CHO and amino acid content of the foliage and roots of asparagus. The highest CHO content and amino acid content were recorded in the treatment that combined PGPR inoculation along with KNO3 fertilizer, indicating that higher K applications acted synergistically with the added PGPR.

Recognition of weeds at asparagus fields using multi-feature fusion and backpropagation neural network

In order to solve the problem of low recognition rates of weeds by a single feature, a method was proposed in this study to identify weeds in Asparagus (Asparagus officinalis L.) field using multi-feature fusion and backpropagation neural network (BPNN). A total of 382 images of weeds competing with asparagus growth were collected, including 135 of Cirsium arvense (L.) Scop., 138 of Conyza sumatrensis (Retz.) E. Walker, and 109 of Calystegia hederacea Wall. The grayscale images were extracted from the RGB images of weeds using the 2G-R-B factor. Threshold segmentation of the grayscale image of weeds was applied using Otsu method. Then the internal holes of the leaves were filled through the expansion and corrosion morphological operations, and other interference targets were removed to obtain the binary image. The foreground image was obtained by masking the binary image and the RGB image. Then, the color moment algorithm was used to extract weeds color feature, the gray level co-occurrence matrix and the Local Binary Pattern (LBP) algorithm was used to extract weeds texture features, and seven Hu invariant moment features and the roundness and slenderness ratio of weeds were extracted as their shape features. According to the shape, color, texture, and fusion features of the test samples, a weed identification model was built. The test results showed that the recognition rate of Cirsium arvense (L.) Scop., Calystegia hederacea Wall. and Conyza sumatrensis (Retz.) E. Walker were 82.72% (color feature), 72.41% (shape feature), 86.73% (texture feature) and 93.51% (fusion feature), respectively. Therefore, this method can provide a reference for the study of weeds identification in the asparagus field. Keywords: weeds recognition, image processing, feature extraction, multi-feature fusion, BP neural network, asparagus field DOI: 10.25165/j.ijabe.20211404.6135 Citation: Wang Y F, Zhang X D, Ma G X, Du X X, Shaheen N, Mao H P. Recognition of weeds at asparagus fields using multi-feature fusion and backpropagation neural network. Int J Agric & Biol Eng, 2021; 14(4): 190–198.

Potential inoculum sources of Fusarium species involved in asparagus decline syndrome and evaluation of soil disinfestation methods by qPCR protocols.

Asparagus decline syndrome (ADS), one of the most important diseases affecting asparagus crops, causes important yield losses worldwide. Fusarium proliferatum, F. oxysporum and F. redolens are among the main species associated with ADS. To explore their potential inoculum sources and the effectiveness of soil disinfestation practices for ADS management, molecular methods based on a quantitative real-time polymerase chain reaction (qPCR) were developed. qPCR-based molecular tools demonstrated advantages in the sensitive and specific detection and quantification of fungal pathogens in comparison with less-accurate and time-consuming traditional culture methods. F. proliferatum, F. oxysporum and F. redolens could be specifically detected and accurately quantified in asparagus plants, soil and irrigation water collected from asparagus fields with ADS symptoms by means of the designed TaqMan qPCR protocols. Furthermore, these molecular tools were successfully applied for evaluation of the efficacy of diverse soil disinfestation treatments. Chemical fumigation with dazomet and biosolarization with pellets of Brassica carinata contributed to a significant reduction in the inoculum densities of the three Fusarium species in treated soils, which was correlated with production increases. The capability to accurately detect and quantify the main Fusarium species involved in ADS in plants, soil and water samples by means of qPCR will allow identification of high-risk fields that can be avoided or managed to reduce yield losses. Quantification of pathogen densities in the soil may also provide essential insights into the effectiveness of soil disinfestation methods for ADS management. © 2021 Society of Chemical Industry.

Recognition of weeds at asparagus fields using multi-feature fusion and backpropagation neural network

In order to solve the problem of low recognition rates of weeds by a single feature, a method was proposed in this study to identify weeds in Asparagus (Asparagus officinalis L.) field using multi-feature fusion and backpropagation neural network (BPNN). A total of 382 images of weeds competing with asparagus growth were collected, including 135 of Cirsium arvense (L.) Scop., 138 of Conyza sumatrensis (Retz.) E. Walker, and 109 of Calystegia hederacea Wall. The grayscale images were extracted from the RGB images of weeds using the 2G-R-B factor. Threshold segmentation of the grayscale image of weeds was applied using Otsu method. Then the internal holes of the leaves were filled through the expansion and corrosion morphological operations, and other interference targets were removed to obtain the binary image. The foreground image was obtained by masking the binary image and the RGB image. Then, the color moment algorithm was used to extract weeds color feature, the gray level co-occurrence matrix and the Local Binary Pattern (LBP) algorithm was used to extract weeds texture features, and seven Hu invariant moment features and the roundness and slenderness ratio of weeds were extracted as their shape features. According to the shape, color, texture, and fusion features of the test samples, a weed identification model was built. The test results showed that the recognition rate of Cirsium arvense (L.) Scop., Calystegia hederacea Wall. and Conyza sumatrensis (Retz.) E. Walker were 82.72% (color feature), 72.41% (shape feature), 86.73% (texture feature) and 93.51% (fusion feature), respectively. Therefore, this method can provide a reference for the study of weeds identification in the asparagus field. Keywords: weeds recognition, image processing, feature extraction, multi-feature fusion, BP neural network, asparagus field DOI: 10.25165/j.ijabe.20211404.6135 Citation: Wang Y F, Zhang X D, Ma G X, Du X X, Shaheen N, Mao H P. Recognition of weeds at asparagus fields using multi-feature fusion and backpropagation neural network. Int J Agric & Biol Eng, 2021; 14(4): 190–198.

Fusarium Consortium Populations Associated with Asparagus Crop in Spain and Their Role on Field Decline Syndrome.

Asparagus Decline Syndrome (ADS) is one of the main phytosanitary problems of asparagus crop worldwide. Diseased plants and soil samples from 41 fields from three main production areas of Spain were surveyed. Eight Fusarium species belonging to seven species complexes were identified in soils: F. oxysporum, F. proliferatum, F. redolens, F. solani sensu stricto, F. equiseti, F. culmorum, F. compactum and F. acuminatum. Fusarium oxysporum was the most prevalent species. Statistical correlation (R2 = 88%) was established between F. oxysporum inoculum density and the average temperature of the warmest month. A relationship was also established between three crop factors (average temperature, crop age and F. oxysporum inoculum density) and field disease indices. Significant differences were observed between the distribution of F. oxysporum propagules in white and green asparagus fields. Thirteen Fusarium species belonging to seven species complexes were identified from roots of diseased plants, being F. oxysporum the most prevalent. F. proliferatum, F. oxysporum and F. redolens showed pathogenicity to asparagus and were the main species associated to ADS. Fusarium oxysporum was the species with the highest genetic diversity displaying 14 sequence-based haplotypes with no geographic differentiation. This work contributes to understanding the Fusarium complex associated to ADS for developing accurate integrated disease management strategies.

Efficacy of mulch and tillage options to reduce runoff and soil loss from asparagus interrows

In the UK, conventional asparagus cultivation practices on sloping land, erodible soils and increased frequency of extreme rainfall events combine to promote runoff generation and soil loss, particularly from interrows. This instrumented field study investigated the interactive effect of mulch and shallow soil disturbance (working depth of 0.175 m) on reducing runoff and soil loss. Ten treatments were installed in a commercial asparagus field near Ross-on-Wye (England, UK) during May 1st–July 17th, 2012. Straw and compost were applied to the interrows at high and low application rates (straw = 5 t ha−1 and 3 t ha−1 and compost = 18 t ha−1 and 8 t ha−1, respectively), both with or without shallow soil disturbance (SSD and Non-SSD) as compared with a bare soil, unamended Control. Across five sampling periods, Non-SSD straw mulch applied at 5 t ha−1 and 3 t ha−1; Non-SSD compost mulch at 18 t ha−1; and straw mulch applied at 5 t ha−1 with SSD all significantly reduced cumulative total soil loss by 53–72% as compared with the Control. Further, mulch treatments with SSD were in general less effective at reducing total soil loss as compared to non-SSD mulch treatments. Compost application was less effective than straw, due to sub-optimal compost blanket depths as dictated by N restrictions for Nitrate Vulnerable Zones, in which the study took place. Despite an overall reduction in total soil loss of 72% (associated with Non-SSD straw mulch applied at 5 t ha−1), soil erosion rates exceeded 1.4 t ha−1 yr−1, considered to be a tolerable erosion rate in the EU. In addition, measured sediment concentrations in the runoff consistently exceeded the EU water quality guideline value of 25 mg l−1. The results indicate that the efficacy of the treatments tested was not adequate to reduce soil erosion in commercial asparagus fields in the UK to tolerable rates. This may in large part be due to daily foot trafficking events that occur during the asparagus harvesting period (April–June) which disturbs and degrades the treatments applied reduing their efficacy. This study demonstrates that additional research is required in order to identify effective erosion control measures to ensure the sustainability of commercial asparagus production systems in the UK.

Susceptibility to Stemphylium vesicarium of asparagus, onion, pear, and rye in Canada

Diseases caused by Stemphylium vesicarium are an increasing problem in the major asparagus and onion production regions of eastern and central Canada. Replicated and repeated controlled environment and field trials were conducted in Ontario to assess the disease reaction of asparagus and onion cultivars to determine if isolates from one crop can cross-infect other hosts, to assess the variation of disease symptoms among cultivars of onion and of asparagus, and to assess the ability of the pathogen to survive in a non-host species. All of the varieties of asparagus and onion assessed were susceptible to infection by S. vesicarium. There were small differences in susceptibility among varieties and in aggressiveness among isolates. These differences were not strongly associated with host crop. Onion cultivars that developed higher numbers of lesions often had lower levels of leaf dieback and vice versa. This indicated that resistance to infection was independent of susceptibility to development of dieback symptoms. In asparagus, infection on spears was not consistently correlated with severity on ferns. All isolates from asparagus and onion produced typical symptoms on wounded, but not unwounded, pear fruit. Finally, the pathogen was shown to colonize and sporulate on necrotic leaves of autumn rye, which is often used as a cover crop in asparagus fields. Stemphylium vesicarium can cross-infect asparagus and onion.

Monitoring and modelling of water and heat fluxes from asparagus fields

Precise estimates of evapotranspiration and other scalar fluxes of asparagus (Asparagus officinalis) crops are required for irrigation control, regional water budget projections or climate impact modelling studies. In Germany, asparagus fields are frequently quite extensive and enable the application of eddy covariance (EC) technique to measure the turbulent fluxes of CO(2), sensible and latent heat (H(2)O) and momentum. In this work we present results of two year EC measurements (2015-16) over an extended asparagus field with commonly used cultivars ('Backlim' and 'Grolim'). With supplementary collected seasonal data of fern area, fern height and several meteorological sensors combined with a sophisticated quality assessment and footprint analysis we are able to parameterize well established physical and physiological crop responses. These include the aerodynamic resistance with separate transfer terms above and within the canopy and the bulk stomatal resistance in a one-layer setting of energy balance formulation. The instantaneous fern canopy conductance is predicted by partial responses of photosynthetic active radiation and fern area, air temperature, air vapour pressure deficit, fern senescence state and the daily canopy to air temperature difference.

Asparagus decline and replant problem: A look back and a look forward at strategies for mitigating losses

Asparagus decline and the replant problem were both defined in the 1950s, but had been noted in asparagus fields long before. Although both conditions share many of the same features, there are distinct differences in the host symptoms and in the age of the field during the onset of symptoms. A number of factors contribute to both disorders. Abiotic factors, such as allelopathic residues, acidic soils, soil compaction, winter crown injury, and excessive harvest pressure, along with biotic agents like insects, weeds, and diseases contribute to decline and the replant problem. Toxic asparagus residues remain the major stressor in the replant problem. Although cultivar improvements along with close attention to reducing stress and disease outbreaks have lessened the damage from asparagus decline and the replant problem, these disorders still make serious inroads into field longevity and yield potential. The presentation will synthesize the results of numerous studies designed to enhance soil health and reduce asparagus decline and the replant problem. An assessment of the direction for future research projects will be presented.

Management of Stemphylium leaf spot (Stemphylium vesicarium) and rust (Puccinia asparagi) of asparagus (Asparagus officinalis) with cultivar selection and fungicides

Stemphylium leaf spot (SLS) and rust are foliar diseases of asparagus fern. If left unmanaged, both SLS and rust can contribute to early decline of an asparagus field and a reduction in yield in subsequent seasons. Currently, growers rely on protectant foliar fungicides and cultivar selection to control foliar disease in asparagus in Canada. However, it is unclear which new cultivars are less susceptible to foliar disease and if any new fungicides might provide adequate control. The objectives of this research were to: (1) assess cultivars and experimental breeding lines for sensitivity to foliar disease, and (2) evaluate fungicides for control of foliar disease in asparagus. A cultivar trial was established in 2011 to compare six cultivars and lines. Also in 2011, thirteen fungicides and combinations of fungicides were assessed for control of foliar disease in ‘Guelph Millennium’. In both studies, the fern was assessed for symptoms of SLS and rust. ‘Jersey Giant’ and ‘Guelph Equinox’ and lines UG010 and UG023 had lower rust severity (as measured as standardized area under the disease progress curve, sAUDPC) than ‘Guelph Millennium’ and ‘Tiessen’. ‘Jersey Giant’ also had lower SLS disease severity index (DSI) and sAUDPC than ‘Guelph Millennium’ and ‘Guelph Equinox’ and the line UG023. There was a negative correlation between SLS and rust for both sAUDPC and DSI assessments. In the fungicide screening trials, differences were observed in lesion counts and sAUDPC. In a 3-year-old field, azoxystrobin/cyproconazole, azoxystrobin/difenoconazole, benzovindiflupyr, cyproconazole, tebuconazole, and the tank-mixture of mineral oil + pigment + propiconazole had lower sAUDPC than the untreated control. In the 4-year-old field, only azoxystrobin/cyproconazole, azoxystrobin/difenoconazole, and cyproconazole had lower sAUDPC than the untreated control. Further research is warranted to investigate rust management programs with fungicides on slow-rusting asparagus cultivars.

Managing runoff and soil loss in asparagus production systems

On slightly sloping land, current asparagus cultivation practices (including prolonged periods of bare soil, surface capping and compaction of wheelings) can lead to runoff and soil loss. This can result in on-site impacts to crops and field operations and offsite impacts on the wider environment. Research into soil and water management in green asparagus production has been undertaken in the UK since 2010. This paper details two separate runoff and erosion trials conducted in 2012 and 2013 on commercial asparagus fields. Each trial has tested the efficacy of a range of treatments applied to inter-row wheelings including green waste compost (of PAS:100 quality protocol standard) and wheat straw mulch at different application rates, both with and without shallow soil disturbance. It was realised early on that compost was ineffective in runoff and soil loss management where application quantity was restricted by nitrogen regulations in Nitrate Vulnerable Zones. Straw mulch alone has consistently reduced soil loss across both trials by 72 to 87% as compared to the bare soil control. Shallow soil disturbance alone reduced soil loss by 4 to 13%, with no significant differences observed between various tillage implements tested. Despite the reductions observed in soil loss, runoff sediment concentration still exceeds that stipulated by EU Directive for surface water quality; risking pollution of any receiving water bodies. The knowledge gained from these studies should be used to develop more effective runoff and soil loss control in order to ensure the future sustainability of asparagus production.