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Problems with aphids in small grain cereals, either direct by feeding, or indirect by transmission of Barley Yellow Dwarf Virus, are expected to increase due to climate change and a recent ban on neonicotinoid seed treatments by the European Union. Moreover, insecticide resistance against pyrethroid insecticides is reported at multiple locations throughout the world. Therefore, a better understanding of cereal aphid population dynamics and increased attention towards an integrated pest management is needed. In this study, cereal aphids were monitored on 193 maize and small grain cereal fields throughout Flanders, Belgium. The population dynamics and species distribution were observed throughout the year and the effects of spatio-temporal variables were explored. A significant negative effect was found of grassland in a 1,000 m radius and a positive effect of grain maize in a 3,000 m radius around a small grain cereals field on the maximum infestation rate with aphids in autumn within this field. In a 3,000 m and 5,000 m radius, a significant positive effect of grain maize and a significant negative effect of other small grain cereals was found on the maximum infestation rate during the whole growing season within this field. The mean daily average temperature from 118 to 19 d before sowing had a significant positive effect on the maximum infestation rate in autumn. Mean precipitation, wind speed, and humidity from 52 to 26, 46 to 23, and 107 to 13 d before sowing respectively, had a significant negative effect on the maximum infestation rate in autumn.

Essential oils have been used since ancient times in traditional medicine and agri-food science to preserve food, and to combat human diseases. Essential oils (EOs) from clove and rosemary, obtained by hydro-distillation, were analyzed by GC/MS and evaluated for their antifungal activity against strains of Aspergillus tubingensis and A. luchuensis and their effect on ochratoxin A (OTA) production by these fungi. The major constituent of clove EO was eugenol (86.4%), and of rosemary EO was eucalyptol (35.9%). Mycelium growth inhibition assays showed that the EOs had dose-depend inhibition effects, which reached 36.6% for rosemary EO, and 100% for clove EO, at EO concentration of 200 μL L-1. These reductions were different for different Aspergillus strains, the essential oil type, and the strain/oil type interaction. Analyses of OTA in the culture medium extracts of Aspergillus strains was carried out using HPLC-FLD, and was confirmed by LC-MS/MS for positive controls of two OTA-producing strains of A. tubingensis. In general, OTA was reduced (from 45 to 100% reduction), except for two strains of A. tubingensis, where OTA production was stimulated.

In a temperate climate, the mycotoxins deoxynivalenol (DON), nivalenol (NIV), enniatin B (ENN B), mycophenolic acid (MPA), roquefortine C (ROC) and zearalenone (ZEN) are often found in maize silage. Although rumen microbiota are able to degrade some mycotoxins (e.g. DON), others are known to stay mainly intact (e.g. ROC). In addition, mycotoxin degradation can be hampered by a low ruminal pH or decrease in rumen microbial activity. Hence, these mycotoxins can reach the small intestine and exert a cytotoxic effect on intestinal epithelial cells. In this study, a real-time kinetic analysis of the cytotoxicity of these six mycotoxins and some of their metabolites (α- and β-zearalenol, α- and β-ZOL) was performed in a calf small intestinal epithelial cell line (CIEB). Confluency as well as the cell death parameters apoptosis and necrosis were determined to evaluate the mycotoxin-induced cytotoxicity. A combination of Annexin-V green and Cytotox red staining was used to determine early and late apoptosis as well as necrosis. Six different concentrations were tested ranging from 0.78 to 12.5 μM. Compared to cells not exposed to mycotoxins, DON and NIV exert a fast toxic effect with DON being more toxic than NIV within the first hours of incubation, whereas the inverse was observed at 16 h of incubation. On the other hand, MPA and ZEN induced increased Annexin V green positive cells within several hours of incubation with higher toxicity over time. Increased Annexin V green and Cytotox red positive cells were seen for ROC only at the highest concentration tested. For ENN B, increased Annexin V green positive cells were observed only after 12 h and α- and β-ZOL did not show cytotoxic effects. Hence, mycotoxin exposure causes either severe (DON and NIV) or more limited (ZEN, ROC, MPA, and ENN B) risk of bovine intestinal epithelial damage.

Fusarium basal rot (FBR) is particularly problematic to Allium producers worldwide. In Vietnam, information on the profile of FBR is scarce, even though the presence of Fusarium spp. in Allium plants has long been recorded. In this study, a total of 180 isolates of Fusarium spp. were recovered from Allium bulbs/plants showing symptoms of FBR in 34 commercial Allium fields around Da Lat, Lam Dong, Vietnam. These isolates were identified to the species level by sequencing the internal transcribed spacer region and the translation elongation factor 1α gene. F. oxysporum was most prevalent (81%) in samples from all locations and Allium varieties, followed by F. solani (15%) and F. proliferatum (4%), which were only found in onion (Allium cepa L.). Pathogenicity tests on onion seedlings (56 isolates) and mini bulbs (10 isolates) indicated that onion can be infected by all of these species but virulence varied greatly between isolates. Moreover, isolates that were virulent on seedlings were sometimes not virulent on bulbs and vice versa, which points to a specialization of isolates for the host phenology. Mycotoxin analyses showed that the highest amounts of beauvericin were detected in seedlings and bulbs infected by F. oxysporum, whereas F. proliferatum was mainly responsible for the presence of fumonisin B1 in bulbs, suggesting a natural occurrence of beauvericin and fumonisin B1 in onions infected by these pathogens.

This study evaluated the agronomic and economic prospects of Site-Specific Seeding (SSS) for consumption and seed potato production based on Management Zone (MZ) maps delineated with the fusion of multiple soil and crop attributes at four experimental sites in Belgium. Soil pH, organic carbon, P, K, Mg, Ca, Na, moisture content, cation exchange capacity, apparent electrical conductivity and crop normalized difference vegetation index were measured with an on-line visible and near-infrared reflectance spectroscopy sensor, electromagnetic induction sensor, and Sentinel-2 constellation, respectively. Spatial alignment of the different data layers generated a co-georeferenced data matrix for data fusion by k-means clustering. Per field MZ classes were ranked according to their fertility status and the prescription rule of sowing more seeds to the more fertile zones and vice versa was adopted and compared against a Uniform Rate Seeding (URS) treatment in a strip plot experiment. Cost–benefit analysis revealed that the SSS improved tuber yields, hence, increased gross margin (137.81 to 457.83 €/ha) of production compared to the URS, although SSS consumed relatively higher amount of seeds. The percentage of gross margin increase varied between 2.34 and 27.21%, with the highest profitability in fields with low productivity. Larger seed-to-seed spacing than the control increased the proportion of the most demanded and profitable tuber category, suggesting the seeding interval is a key determinant of tuber size distribution. It is suggested to adopt SSS for potato production using the proposed multi-sensor data-fusion approach to manage in-field soil and crop variabilities, and improve productivity and profitability.

Buckwheat is an important starch source because of its health benefits. In this study, buckwheat starches isolated from 12 varieties were analyzed based on the morphological, structural and physicochemical properties. The results showed that starch samples from different varieties had high purity with the total starch ranging from 91.29 to 95.11%, while showing significant differences in ash content (0.12-0.25%), protein content (0.26-0.34%) and amylose content (29.55-36.13%), respectively. All samples presented spherical and irregular shapes and typical A-type crystalline structure, but obvious differences in granule size distribution and relative crystallinity (26.37-35.21%) were observed among 12 varieties. Starch samples differed in lamellar structures, showing higher values of thickness of the samples with higher amylose content. In addition, buckwheat starches with higher amylose content showed higher values in light transmittance and rheological properties, while starch samples with lower amylose content obtained higher values in terms of water solubility, swelling power, pasting behaviors and thermal parameters. The principal component analysis and cluster analysis based on starch property parameters indicated that there were significant similarities and differences among 12 varieties, which might be related to the genotypes. This study would provide valuable information for the full use of buckwheat starch in food and non-food industries.

Aims: To determine the chemical composition of essential oil of Ageratum conyzoides with antifungal activity on the strain of Lasiodiplodia theobromae in the Kisangani region. Location and Duration of Studies: Faculty of Sciences of University of Kisangani (Democratic Republic of Congo) and Faculty of Biosciences Engineering of University of Ghent (Belgium), between May to November 2019. Methodology: The essential oil from the leaves of A. conyzoides was extracted by hydrodistillation. Potato dextrose agar (PDA) was used as a culture medium. In vitro evaluation of its antifungal activity was performed on PDA medium and expressed as percentage of inhibition (PI). Results: The extracted essential oil (with a yield of 0.63%) showed a PI of 91.63% on the strain of L. theobromae after two days of incubation. It consists of at least 23 compounds, of which seven are in the majority (abundances greater than 1.5% and represent 92.05%), namely Precocene I (38.33%), Beta-caryophyllene (26.51%), Beta-sesquiphellandrene (8.63%), Beta-cubebene (7.91%), Alpha-muurolene (4.95%), 1.5.9.9-Tetramethyl-1.4.7-cycloundecatriene (3.04%), Cis-beta-farnesene (2.99%). The hydrocarbon sesquiterpenes are the most frequent compounds (58.95%). Discussion: Compared to the A. conyzoides saponins the PI obtained from the essential oil is higher. The essential oil chemotype obtained from the leaves of A. conyzoides is of the Precocene I type, similar to the oils from the stems and flowers of the same plant in West Africa. Conclusion: The essential oil of A. conyzoides has a very high inhibitory power on L. theobromae. It mainly contains the Precocene and the hydrocarbon sesquiterpenes. Assessment of the antifungal activity of each separate molecule should be considered.

Background Gaining insight into crop diversity, both at the genetic and phenotypic levels, is of prime importance for onion breeding with an enhanced yield and quality in combination with improved resistance to biotic and abiotic stresses. In the current study, 192 different onion plants, representing 16 ecotypes, were characterized using ISSR markers. Results Based on the ISSR marker profile, there was a clear grouping of the plants into 16 different ecotypes. Though the 16 populations originated from the same geographic region in Morocco, a significant genetic diversity was detected. After a genomic characterization, field trials in three different environments in Morocco were laid out. The phenotypic characterization showed that there were always significant differences between ecotypes, and for most traits, there was also a significant environmental effect and a significant interaction between environment and ecotype. The broad-sense heritability (H2) for the phenotypic traits associated with color (L*, a*, and b*) was the largest (84.2%, 80.6%, 79.2%), demonstrating that color is conditioned primarily by genetic factors. In contrast, the H2 for yield was the lowest (41.8%), indicating that the environment has a substantial effect on yield. In addition, there was a significant association between the presence/absence of certain bands and various phenotypic traits. Conclusion ISSR markers are a powerful tool in distinguishing onion ecotypes. In addition, significant associations between marker scores and phenotypic traits could be detected, representing particular importance for future breeding programs.

Aims: To extract, identify and evaluate in vitro the antifungal activity of the phytochemical groups of Ageratum conyzoides and Newbouldia laevis on the strain of Lasiodiplodia theobromae. Study Design: Exploitation of medicinal plants to combat the growth of L. theobromae, responsible for the decline of cocoa cultivation. Location and Duration of Studies: Faculty of Sciences, University of Kisangani, between April 2017 and February 2018. Methodology: The crude extracts of the dry leaves of A. conyzoides and N. laevis were tested (at 100 mg/mL). Potato dextrose agar was used as the culture medium. After chemical screening, abundant phytochemical groups were isolated and tested. Results: The aqueous, 95% ethanolic and ethereal crude extracts of A. conyzoides are more antifungal (respective percentages of inhibition PI: 80.74; 84.10 and 85.64%) than those of N. laevis (63.28; 72.64 and 75.23%). The minimum inhibitory concentration (MIC) of the aqueous crude extract of A. conyzoides is lower (25 mg/mL) than that of the ethanolic extract (50 mg/mL). Tannins are very abundant in A. conyzoides and in N. laevis. Saponins, sterols and terpenes are abundant in both plants. The extraction yields of tannins and saponins are respectively 20.67 and 2.43% in A. conyzoides and 10.47 and 2.38% in N. laevis. A. conyzoides contains the gallic tannins while N. laevis, the condensates and catechics. The saponins and tannins of A. conyzoides are more antifungal (respective PI: 84.40 and 54.44%) than those of N. laevis (PI: 75.56 and 32.96%). Discussion: The saponins of A. conyzoides and N. laevis are more active on the strain of L. theobromae than the tannins. Saponins are surfactants that can destabilize membrane structure of microorganisms including fungi. Conclusion: The saponins of the two plants have shown a very interesting antifungal power on the strain of L. theobromae. The identification of their active molecules is ongoing.

Tropical soils are mostly poor in phosphorus and sometimes in nitrogen and potassium. Arbuscular mycorrhizae increase the efficiency of chemical fertilizers applied to crops, and this work is part of this framework. NPK (nitrogen-phosphorus-potassium) was applied at 100 kg per ha and 200 kg per ha alone or in combination with inoculum from sorghum or leek in soil (pH 4.28). The trial was conducted on a 3 × 3 split-plot design with 3 replicates. Plant height, number of leaves and chlorophyll level in the leaves were evaluated. The frequency of root colonization by mycorrhizal fungi was also studied. The number of pods per plant, the number of seeds per pod and the yield were also evaluated. The results showed that vegetative parameters increased with the addition of fertilizers while production parameters varied little with fertilizers but significantly, when these fertilizers were associated with mycorrhizal inoculum. Treatments with 200 kg NPK combined with sorghum inoculum produced 512 kg of beans per ha, while 200 kg NPK alone produced 278 kg of beans per ha.

Summary The transition to sustainable agriculture and horticulture is a societal challenge of global importance. Fertilization with a minimum impact on the environment can facilitate this. Organic fertilizers can play an important role, given their typical release pattern and production through resource recovery. Microbial fertilizers (MFs) constitute an emerging class of organic fertilizers and consist of dried microbial biomass, for instance produced on effluents from the food and beverage industry. In this study, three groups of organisms were tested as MFs: a high‐rate consortium aerobic bacteria (CAB), the microalga Arthrospira platensis (‘Spirulina’) and a purple non‐sulfur bacterium (PNSB) Rhodobacter sp. During storage as dry products, the MFs showed light hygroscopic activity, but the mineral and organic fractions remained stable over a storage period of 91 days. For biological tests, a reference organic fertilizer (ROF) was used as positive control, and a commercial organic growing medium (GM) as substrate. The mineralization patterns without and with plants were similar for all MFs and ROF, with more than 70% of the organic nitrogen mineralized in 77 days. In a first fertilization trial with parsley, all MFs showed equal performance compared to ROF, and the plant fresh weight was even higher with CAB fertilization. CAB was subsequently used in a follow‐up trial with petunia and resulted in elevated plant height, comparable chlorophyll content and a higher amount of flowers compared to ROF. Finally, a cost estimation for packed GM with supplemented fertilizer indicated that CAB and a blend of CAB/PNSB (85%/15%) were most cost competitive, with an increase of 6% and 7% in cost compared to ROF. In conclusion, as bio‐based fertilizers, MFs have the potential to contribute to sustainable plant nutrition, performing as good as a commercially available organic fertilizer, and to a circular economy., Microbial fertilizer performed equal or even better in the fertilization of petunia and parsley. Microbial fertilizers showed promising quality which was preserved during storage. CAB and a blend of CAB/PNSB are the most cost‐effective fertilizer alternatives with an increase of 6 and 7% in cost price.

Acute stunting in children, liver cancer, and death often occur due to human exposure to aflatoxins in food. The severity of aflatoxin contamination depends on the type of

Rye (Secale cereale subsp. cereale L.) has long been exploited as a valuable alternative genetic resource in wheat (Triticum aestivum L.) breeding. Indeed, the introgression of rye genetic material led to significant breakthroughs in the improvement of disease and pest resistance of wheat, as well as a few agronomic traits. While such traits remain a high priority in cereal breeding, nutritional aspects of grain crops are coming under the spotlight as consumers become more conscious about their dietary choices and the food industry strives to offer food options that meet their demands. To address this new challenge, wheat breeding can once again turn to rye to look for additional genetic variation. A nutritional aspect that can potentially greatly benefit from the introgression of rye genetic material is the dietary fibre content of flour. In fact, rye is richer in dietary fibre than wheat, especially in terms of arabinoxylan content. Arabinoxylan is a major dietary fibre component in wheat and rye endosperm flours, and it is associated with a variety of health benefits, including normalisation of glycaemic levels and promotion of the gut microbiota. Thus, it is a valuable addition to the human diet, and it can represent a novel target for wheat–rye introgression breeding.

‘Candidatus Liberibacter solanacearum’ is an economically important pathogen in the Americas, New Zealand and Europe. The primary objective of this review is to systematically investigate the polymerase chain reaction (PCR)-based methods used for its detection in plant samples. Several databases were searched from the inception of the relevant literature up to August 2018. This review identified 53 studies that met all the inclusion criteria. The performance of the different methods was also compared, however due to data heterogeneity and insufficient evidence on the sensitivity of all assays used, a meta-analysis of the data was not possible. Nonetheless, the review indicates that the rtPCR designed to the 16S ribosomal RNA gene can be routinely employed as a fast, cost-effective, and reliable detection technique in diagnostic laboratories.

With nematicides progressively being banned due to their environmental impact, an urgent need for novel and sustainable control strategies has arisen. Stimulation of plant immunity, a phenomenon referred to as “induced resistance” (IR), is a promising option. In this study, Cucurbitaceae COld Peeling Extracts (CCOPEs) were shown to protect rice (Oryza sativa) and tomato (Solanum lycopersicum) against the root-knot nematodes Meloidogyne graminicola and Meloidogyne incognita, respectively. Focusing on CCOPE derived from peels of melon (Cucumis melo var. cantalupensis; mCOPE), we unveiled that this extract combines an IR-triggering capacity with direct nematicidal effects. Under lab conditions, the observed resistance was comparable to the protection obtained by commercially available IR stimuli or nematicides. Via mRNA sequencing and confirmatory biochemical assays, it was proven that mCOPE-IR in rice is associated with systemic effects on ethylene accumulation, reactive oxygen species (ROS) metabolism and cell wall-related modifications. While no negative trade-offs were detected with respect to plant growth or plant susceptibility to necrotrophic pests or pathogens, additional infection experiments indicated that mCOPE may have a predominant activity toward biotrophs. In summary, the presented data illustrate a propitious potential for these extracts, which can be derived from agro-industrial waste streams.

Pre-anthesis drought is expected to greatly increase yield losses in wheat (

Mycotoxin food contamination data is scattered, isolated, and poorly described. Reporting mycotoxin contamination data in a standardized manner is essential for collaborative research and integrated large-scale data analysis. The present study aimed to complement the existing European Food Safety Authority (EFSA) and Global Environment Monitoring System (GEMS) mycotoxin contamination data descriptors for application in low- and middle-income countries in particular. A three-round Delphi process was followed to establish a consensus on the missing descriptors. An invitation letter was first sent to 34 mycotoxin experts of an international collaboration of MYTOX-SOUTH®, of which 12 finally participated in the study. The response rate was 29.4% (10/34) in the Delphi I, 75% (9/12) in the Delphi II, and 83.3% (10/12) in the Delphi III rounds. The majority of the Delphi study participants were professors from 6 universities. Twenty-two descriptors (17 study level, 1 sample level, and 4 assay level) were proposed and were mainly related to pre and post-harvest periods of a food/feed sample. The pre-defined (>70% in the Delphi II and > 80% in the Delphi III) agreement among participants was achieved for all the proposed descriptors. The existing descriptors from EFSA (33) and GEMS (25) with the new proposed MYTOX-SOUTH® (22) descriptors, in total 80 descriptors, were arranged as study, sample, and assay categories and organized as a data submission template. Pre-testing of the template on three mycotoxin researchers indicated that the average time to fill out the form for a sample was 42 min. The current format helps mycotoxin contamination data to become more informative, reusable, and applicable especially to data from low- and middle-income countries. The above-proposed descriptors will help GEMS to provide technical cooperation with countries wishing to initiate and strengthen food contaminant monitoring programs. Similarly, the descriptors from the current study will be useful for EFSA as it regularly updates the Standard Sample Description. A standardized global reporting format for mycotoxin contamination data will enable national authorities to perform mycotoxins exposure and risk assessments and share data for international benchmarking. Standardized reporting and sharing of mycotoxin contamination data should be further advocated in ongoing research and become common practice in authorities, companies, academia, and other entities working on mycotoxin in food and feed.

Tillage is an important agricultural practice, influencing the physical, chemical and biological soil characteristics. In this paper the influence of various tillage systems combined with or without a cover crop under different nitrogen fertilization levels on silage maize yield and soil fertility was investigated. Based on a field trial in Bottelare (Belgium), during the period 2007-2015, it was concluded that for each tillage system higher nitrogen levels resulted in a higher yield. In addition, the highest yield was achieved for the conventional tillage system, the yield gain for mouldboard ploughing varied between 13% (2015) and 71% (2012) compared to zero tillage. In case reduced tillage was adopted, the yield loss compared to mouldboard ploughing varied between 6% (2013 and 2015) and 24% (2012). Furthermore, it seemed that the accumulated temperature during the growing season and rainfall around flowering were decisive in determining maize yield. Additionally, rainfall in the period 60 days post sowing was significantly negatively correlated with the yield from the zero tillage plots, whereas in case tillage was adopted no correlations with rainfall 60 days post sowing were detected. Concerning the soil organic carbon content and the amount of earthworms, no clear trends could be observed. Zero tillage resulted in high weed pressure and caused soil compaction. So, in this trial, under humid conditions, the less labor intensive zero tillage system did not result in competitive maize yields. In conclusion, reduced tillage methods offer opportunities for maize cultivation in Belgium. This method of farming resulted in a lower yield, however, the difference with mouldboard ploughing was not significant. Therefore, adopting a reduced tillage system can be seen as a valid alternative for ploughing as this tillage system ensures a sustainable environment.

Lupin is prone to infection by Pleiochaeta setosa (Kirchn.) Hughes causing brown spot and root rot in Lupinus species. The control of these diseases is crucial to limit yield losses, but an increased public awareness and European legislative restrictions have resulted in a drastic reduction of allowed pesticides and many research groups invest in alternative biocontrol strategies. In the current study, the inhibitory effect of volatiles, released by two members of the Brassicaceae family (white mustard (Sinapis alba) and fodder radish (Raphanus sativus)), on brown spot and root rot in Lupinus species was evaluated in vitro and in vivo. The in vitro trial showed that root tissue of Brassicaceae was more effective in reducing the vegetative growth of Pleiochaeta setosa than leaf and stem tissues. Furthermore, R. sativus was more effective than S. alba. The GC-MS analysis revealed that dimethyl disulfide and dimethyl trisulfide were predominantly emitted by the tissues of both Brassicaceae. Additionally, the ground root tissue of R. sativus emitted 4-isothiocyanato-1-(methylthio)-1-butene, whereas the stem + leaf tissue emitted benzyl isothiocyanate. Benzyl isothiocyanate was also released by the ground S. alba root tissue, whereas the leaf + stem tissue emitted 3-butenyl isothiocyanate. In vitro trials with pure dimethyl disulfide and dimethyl trisulfide confirmed the antifungal effect of the volatiles released by these sulfides. For dimethyl disulfide 7.95 mg per Petri dish was necessary to (almost) completely inhibit mycelium growth, whereas for dimethyl trisulfide 1.20 mg per Petri dish was sufficient to prevent fungal growth. In addition, a trial with allyl isothiocyanate showed that for this compound even lower doses (0.50 mg per Petri dish) stopped the growth of the fungus. The results obtained with the pot trial illustrated that the amendment of Brassicaceae species significantly reduced the P. setosa infection level. Also in the field, incorporation of Brassicaceae species suppressed P. setosa. From this study, it can be concluded that Brassicaceae species are a powerful tool to manage P. setosa in lupin cultivation. However, it should be combined with other control practices since the amendment of these biofumigant crops could not completely inhibit symptom development.

To restore species-rich grasslands on former agricultural land, typically phosphorus-poor soil conditions need to be re-established. Here we assess the potential of phosphorus extraction by biomass production, i.e. phytomining. We compare two techniques: (i) ‘mowing’, i.e. cutting and removing hay two or three times a year, and (ii) ‘P-mining’, i.e. mowing with yield maximization by adding growth-limiting nutrients other than phosphorus (i.e. nitrogen and potassium). In a five-year field experiment at three fields situated along a soil phosphorus gradient, we studied phosphorus removal through both biomass assessment and changes in two soil phosphorus pools: bioavailable phosphorus (POlsen) and slowly cycling phosphorus (POxalate). Phosphorus-mining doubled the phosphorus removal with biomass compared to mowing, and phosphorus removal with biomass was lower at fields with an initially lower concentration of POlsen in the soil. The POlsen concentrations decreased significantly during the experiment with the largest decreases in phosphorus-rich plots. Changes in the POlsen and POxalate stocks were correlated with the amount of phosphorus removed with biomass. Phosphorus-mining effectively increases phosphorus removal compared to mowing, but becomes less efficient with decreasing soil phosphorus concentrations. Restoring phosphorus-poor soil conditions on formerly fertilized land remains a challenge: phytomining most often needs a long-term commitment.

Cereal leaf beetles (CLBs), a group of chrysomelid beetles of the genus Oulema (Coleoptera: Chrysomelidae), are well-known pest insects of small-grain cereals in many countries of the Northern hemisphere. Due to the small differences in morphology of species within this genus, classification up to species level remains a challenging task. Since an accurate view of species composition is important for developing targeted control strategies, the goal of this study was to unravel the Oulema species composition in Flanders’ wheat fields. During three subsequent years at a series of different fields, Oulema species were collected and classified up to species level (2016: 28 fields, 2017: 30 fields, and 2018: 23 fields). This study reveals that the population consists of four different species: Oulema melanopus, Oulema duftschmidi, and Oulema obscura were most frequently encountered, while Oulema rufocyanea was only marginally present. Furthermore, the population was highly dynamic, as the population share of each species varied between different growing seasons and between the various sampling events within each season. The distance from the field edge had a minor influence on the species composition, but the abundance of beetles increased with the distance to the field edge. A discriminant analysis revealed that based on the measurements of various body parts, an accurate classification up to species level is possible. In conclusion, we observed that the population densities fluctuated within and between years, resulting in variable incidence of CLB in winter wheat fields in the Flanders region.

Soil organic carbon (OC) levels generally increase with increasing clay and silt content under a similar climatic zone because of increased association of OC to clay minerals and stronger occlusion inside aggregates. Surprisingly though, in Western Europe many silt loam soils actually bear low topsoil OC levels compared to lighter textured soils. Soil texture obviously also strongly controls moisture availability with consequent indirect impact on heterotrophic activity. We hypothesized that with increasingly frequent summer drought: 1) soil microbial activity in sandy soils is more likely impeded due to their limited water holding capacity retention during droughts, while soil OC mineralization in silty soils remain be less drought-limited; 2) capillary rise from sufficiently shallow groundwater would, on the other hand, alleviate the water stress in lighter textures. To test these hypotheses, we established a one-year field trial with manipulation of soil texture, monitoring of soil moisture and maize-C decomposition via 13/12C-CO2 emissions. The upper 0.5 m soil layer was replaced by sand, sandy loam and silt loam soil with low soil OC. Another sandy soil treatment with a gravel layer was also included beneath the sand layer to exclude capillary rise. Soil texture did not affect maize-C mineralization (Cmaize-min) until April 2019 and thereafter Cmaize-min rates were higher in the silt loam than in the sandy soils (P=0.01). θv correlated positively with the Cmaize-min rate for the sand-textured soils only but not for the finer textures. These results clearly highlight that soil texture controlled Cmaize-min indirectly through regulating moisture under the field conditions starting from about May, when soils faced a period of drought. By the end of the experiment, more added Cmaize was mineralized in the silt loam soil (81%) (Pmaize-min in the sandy soil, seemingly because the capillary fringe did not reach the sandy topsoil layer. These results imply that, under future climate scenarios the frequency of drought is expected to increase, the largely unimpeded microbial activity in silty soils might lead to a further stronger difference in soil OC with coarser textured soils under similar management.

Fusarium basal rot (FBR) is particularly problematic to

Soil organic carbon (SOC) levels generally increase with increasing clay and silt content under similar climatic conditions because of increased physicochemical protection. Surprisingly though, many silt loam soils in Western Europe have low top SOC levels compared to coarser textured soils. Soil texture also strongly controls soil moisture with consequent indirect impact on heterotrophic activity. Especially during periods of prolonged drought, which seem to be occurring more frequently throughout Europe, it could be expected that this soil textural control of moisture retention decisively affects added organic matter (OM) decomposition. We hypothesized that, contrary to expected textural effects on physicochemical protection of OM, the higher moisture availability in silty soils strongly favors added OM mineralization during periodic drought than sandy soils. Moreover, as a secondary objective, we investigated if during prolonged drought, capillary moisture supply could significantly alleviate the water stress on added OM decomposition in sand with rather shallow groundwater table. Therefore, we established a one-year field trial in which the upper 0.5 m soil layer was replaced by sand, sandy loam and silt loam soil with low SOC. In a fourth treatment, a gravel layer was added beneath the sand layer to exclude capillary rise. Maize residues were mixed homogenously with soil in top 25 cm in all plots. Changes in soil moisture and maize-C mineralization (C-maize-min) were measured. We found that soil texture did not affect C-maize-min until after about five months and thereafter C-maize-min rates were higher in the silt loam than in the sandy soils. Moisture content correlated positively with the C-maize-min rate for the sand-textured soils only. Capillary rise did not result in a significant increase in C-maize-min in the sandy soil. After one year, a larger share of added C-maize was mineralized in the silt loam soil (81 +/-& nbsp; 6%) than in the sandy soil (56 +/- 7%). These results clearly highlight that soil texture controlled C-maize-min indirectly through regulating moisture under the field conditions when the study area faced a period of unusual drought. Moreover, our results imply that, under future climate scenarios, more frequent droughts might lead to a lesser SOC depletion in sandy soils compared to in finer textured soils under similar management.

BACKGROUND Driven by environmental concerns, chemical fumigants are no longer allowed in many countries. Therefore, other strategies for reducing fungal inoculum in soils and on crop debris are being explored. In the present study, several Brassicaceae crops were screened for their potential to control Fusarium gramineaum and Fusarium poae mycelial growth in an in vitro inverted Petri dish experiment. Volatile production was measured using gas chromatography-mass spectrometry headspace analysis. A selection of cultivars from each crop species was further investigated using a pot experiment with maize. RESULTS Ethiopian mustard (Brassica carinata) and brown mustard (Brassica juncea) released volatile allyl isothiocyanate (AITC) and a higher concentration of AITC was correlated with a better fungal growth reduction in the in vitro screening. Brown mustard cultivar Etamine completely inhibited growth of both Fusarium spp. Pure AITC in a solution with methanol resulted in a sigmoid dose-response curve for both Fusarium spp. tested. Fusarium poae appeared to be more tolerant to AITC than F. graminearum. A pot experiment revealed that the incorporation of brown mustard plant material could alleviate the clear negative effect of F. graminearum infection on maize growth. CONCLUSION The present study demonstrated the correlation between the fungistatic effect of biofumigation crops on Fusarium spp. and their production of volatile AITC in vitro, without the addition of exogenous enzymes, and confirmed the biofumigation potential of brown mustard in a pot experiment with maize. These results may help farmers when selecting a green manure crop suitable for biofumigation. © 2020 Society of Chemical Industry.

Site-specific seeding (SSS) is a precision agricultural (PA) practice aiming at optimizing seeding rate and depth, depending on the within field variability in soil fertility and yield potential. Unlike other site-specific applications, SSS was not adopted sufficiently by farmers due to some technological and practical challenges that need to be overcome. Success of site-specific application strongly depends on the accuracy of measurement of key parameters in the system, modeling and delineation of management zone maps, accurate recommendations and finally the right choice of variable rate (VR) technologies and their integrations. The current study reviews available principles and technologies for both map-based and senor-based SSS. It covers the background of crop and soil quality indicators (SQI), various soil and crop sensor technologies and recommendation approaches of map-based and sensor-based SSS applications. It also discusses the potential of socio-economic benefits of SSS against uniform seeding. The current review proposes prospective future technology synthesis for implementation of SSS in practice. A multi-sensor data fusion system, integrating proper sensor combinations, is suggested as an essential approach for putting SSS into practice.

Organic fertilizers and especially microbial biomass, also known as microbial fertilizer, can enable a paradigm shift to the conventional fertilizer-to-food chain, particularly when produced on secondary resources. Microbial fertilizers are already common practice (e.g. Bloom® and Synagro); yet microbial fertilizer blends to align the nutrient release profile to the plant’s needs are, thus far, unexplored. Moreover, most research only focuses on direct fertilization effects without considering added value properties, such as disease prevention. This study has explored three promising types of microbial fertilizers, namely dried biomass from a consortium of aerobic heterotrophic bacteria, a microalga (Arthrospira platensis) and a purple non-sulfur bacterium (Rhodobacter sphaeroides). Mineralization and nitrification experiments showed that the nitrogen mineralization profile can be tuned to the plant’s needs by blending microbial fertilizers, without having toxic ammonium peaks. In a pot trial with perennial ryegrass (Lolium perenne L.), the performance of microbial fertilizers was similar to the reference organic fertilizer, with cumulative dry matter yields of 5.6–6.7 g per pot. This was confirmed in a pot trial with tomato (Solanum lycopersicum L.), showing an average total plant length of 90–99 cm after a growing period of 62 days for the reference organic fertilizer and the microbial fertilizers. Moreover, tomato plants artificially infected with powdery mildew (Oidium neolycopersici), a devastating disease for the horticultural industry, showed reduced disease symptoms when A. platensis was present in the growing medium. These findings strengthen the application potential of this novel class of organic fertilizers in the bioeconomy, with a promising match between nutrient mineralization and plant requirements as well as added value in crop protection.

Late blight caused by the oomycete Phytophthora infestans is considered the biggest threat to potato farming worldwide. For susceptible cultivars, the disease is often managed by frequent applications of fungicides to reduce yield loss. The use of bio-based compounds that interfere with biologically active systems is an innovative strategy for improving disease management. In the present work, the control of P. infestans infection on potatoes by potassium phosphite (KPhi) combined with recommended and reduced doses of active ingredients (Ais) from different fungicides was evaluated. The protective effects of different combinations were initially assessed in vivo and subsequently compared with a greenhouse screening. The active ingredients cyazofamid (CFD) and mancozeb (MCB), used at recommended and reduced doses, were less effective at reducing P. infestans infections than when combined with KPhi. In greenhouse trials, CFD, mandipropamid (MPD) and MCB at recommended doses were the most effective treatments when combined with KPhi; meanwhile, the combination of KPhi with azoxystrobin (AZ), benthiavalicarb-isopropyl/mancozeb (ISO/MCB), and CFD at reduced doses exhibited strong protective activity compared to other similar combinations. This decreased the severity of infection by P. infestans up to ~89%. Greenhouse experiments also demonstrated that a combination of KPhi and CFD at both doses caused the highest reduction in disease severity (up to ~90%) within 35 days of infection. In microplot experiments, KPhi delayed the progression of late blight in susceptible potato varieties; therefore, in the combined treatments AUDPC values were significantly lower than those obtained after applications with CFD doses, providing sufficient protection against late blight. Our data suggest that optimizing the formulation with addition of KPhi could result in a lower recommended dose. This would result in a reduction of the active compounds of the fungicides in potato farming. Furthermore, the impact of KPhi on late blight development makes it a potential component for incorporation into an integrated pest management system.

A cluster randomised controlled trial was performed in three agro-ecological zones of Tanzania to evaluate the effectiveness of locally available post-harvest mitigation strategies in preventing and reducing aflatoxin and fumonisin contamination in maize. A total of 300 children, each from one household, were randomly selected from 30 villages (intervention: n=15). The mitigation strategies focused on hand sorting (prior to storage and use), drying maize on mat/raised platforms, proper sun drying, application of storage insecticides and de-hulling before milling. Maize sample was collected from each household at harvest (baseline) and six months after harvest. Maize intake by each child, estimated using the 24 h dietary recall technique and its body weight measured using standard procedures were taken at six months after harvest. Aflatoxins and fumonisins in the maize samples were determined using HPLC. Follow-up (six month after harvest) data were available for 261 of the 300 households (intervention: n=136). Mean concentration of aflatoxins, or fumonisins was significantly (P

Wheat (Triticum spp.) is among the top cereal grains in terms of production and consumption in Ethiopia. It can be typically infected with ochratoxin A (OTA) producing fungi both in the field and during storage resulting in animal and human health problems. While there is a wealth of information on the presence of OTA in wheat, the incidence of OTA in teff (Eragrostis tef), a cereal grain produced and consumed traditionally in Ethiopia and Eretria, remains insufficient. The purpose of this study was to develop and validate a high performance liquid chromatography (HPLC) method for OTA analysis in teff and wheat flours and to analyse the characteristic distribution of OTA in teff and wheat flours samples destined for local consumption in Ethiopia using a survey-approach. Wheat and teff flour samples were examined for OTA contamination. OTA was detected in 20% of the teff flour samples and in 50% of the wheat flour samples with median contamination levels of 1.04 μg/kg (limit of detection (LOD) = 0.78 μg/kg) and 7.23 μg/kg (LOD = 0.58 μg/kg) respectively. The validated method for OTA detection and quantification in teff and wheat using HPLC meets the European Union performance criteria for OTA (EC 2006/401) and the Eurachem Guideline validation requirements. An insight into the occurrence of OTA in teff is very valuable because the cereal might provide a lower OTA risk alternative for wheat in Ethiopia. In addition, for the world market, an insight into the occurrence of OTA in teff is important in the light of an increasing interest in teff as a gluten free cereal.

Future increase in drought and heat stress will challenge legume productivity in many regions. In Sub-Saharan Africa, legumes are earmarked as an integral component in building resilience to climate change and food security in smallholder farming systems. Hence, the need for continuous screening of drought tolerant legume genotypes for sustained productivity. A 2-yr field study was conducted to identify superior cowpea genotypes with high biological nitrogen fixation (BNF), grain yield, and drought tolerance. Four genotypes, selected from a pool of 91, were grown under four moisture levels ranging from well-watered (WW) to severe water stress (SS). Grain yield, shoot biomass, nodule mass, and BNF were determined. There was significant effect of water stress on the measured parameters. Nodule mass and BNF were more sensitive to water stress compared to shoot biomass across genotypes. Water stress resulted in 80% reduction in nodule biomass between WW and SS. As a result, cowpea genotypes grown under SS conditions fixed 57% less N-2 compared to those under WW. The study also revealed significant genotypic variation in shoot biomass, grain yield, and BNF. Genotype TVu4607 was low in grain yield but performed better for BNF (71 kg N ha(-1) under WW and 30 kg N ha(-1) under SS). Genotype IT00K-1263, proved to be our superior genotype with a good balance of biomass, BNF and grain yield. Our findings suggest that future water stress may significantly affect cowpea productivity, mostly its capacity to fix nitrogen. Consequently, adaptation strategies to improve drought resistance in cowpea are needed, particularly improvement of BNF under water stress.

AIMS: The present study was conducted to evaluate the antagonistic effect of Bacillus velezensisNRRL B‐23189 towards Penicillium roqueforti s.s. and Penicillium paneum (designated together as P. roqueforti s.l.) in silage conditions. METHODS AND RESULTS: Corn silage conditions were simulated in vitro, and the impact of B. velezensis culture supernatant or cell suspension on P. roqueforti s.l. growth and roquefortine C production was evaluated. The antagonism was promising, but growth of B. velezensis in corn silage infusion was poor. Additionally, an in vivo experiment was carried out with mini‐silos containing a mixture of perennial ryegrass and white clover inoculated with P. roqueforti s.l. The applied B. velezensis cell suspension was unsuccessful in reducing P. roqueforti s.l. numbers, but did not compromise the silage acidification. CONCLUSIONS: Although the antagonism observed in vitro was promising, the applied B. velezensis cell suspension could not live up to the expectations in vivo. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, the present study is the first one evaluating the antagonistic properties of B. velezensis towards toxigenic moulds in silage conditions, offering a good base for further research.

Lupin (Lupinus L.) has the potential to become a true alternative for soybean as protein source, especially in the more temperate regions in the world. However, diseases such as anthracnose (Colletotrichum lupini), gray mold (Botrytis cinerea), and root rot or brown spot (Pleiochaeta setosa) are important threats for lupin production, leading to yield and quality losses. Although conventional fungicides offer a solution to these problems, there is a growing interest in the use of alternative (biological) treatments. In this research, the applicability of four pure plant essential oils (clove oil, juniper oil, tea tree oil, and thyme essential oil) and timbor® (a Thymus vulgaris-derived plant extract) as alternatives for synthetic fungicides towards the lupin pathogens—C. lupini, B. cinerea, and P. setosa—was investigated. The anti-fungal effect of juniper oil was limited, whereas the other oils and timbor® clearly suppressed the growth and spore germination of all fungi. The in vitro experiments revealed that thyme essential oil and timbor® were most effective to inhibit conidial germination and mycelium growth. Furthermore, the results of the pot experiments demonstrated that these Thymus-derived compounds were able to suppress P. setosa brown spot and root rot symptoms. Additional trials are necessary to evaluate the effect of these compounds under field conditions. However, based on these in vitro and pot experiments, it can be concluded that pure essential oils and Thymus-derived plant extracts are promising anti-fungal agents, having the potential to become true alternatives for conventional fungicides in lupin cultivation. To the best of our knowledge, this is the first study demonstrating the potential of plant-derived compounds to treat the main diseases affecting lupin production.

The main goal of this study is to gain insight into the relationship between the genetic profile of cultivated rice (Oryza spp.) accessions and their resistance to rice blast. Therefore, the genetic and phenotypic variability of a set of 350 cultivated rice accessions originating from Africa (Benin, Mali and Nigeria, Ivory Coast etc.) was examined. Seventy-seven fluorescent amplified fragment polymorphism (AFLP) markers were used to gain insight into the genetic variation and to classify the germplasm collection. In addition, the rice germplasm was assessed for its resistance to blast disease caused by Pyricularia oryzae in upland field conditions. Huge differences in responses of rice accessions to P. oryzae were observed, ranging from highly susceptible to highly resistant. Twelve percent of all accessions were highly resistant to P. oryzae. Based on their AFLP marker profile these highly resistant accessions could be separated from the other accessions. Stepwise regression revealed that the best prediction of the blast resistance level was achieved with a maximum number of 13 AFLP markers. Marker CTA22 was the most important for accurate prediction of blast resistance, this marker was present in all highly resistant accessions. It can be concluded that AFLP markers are a valuable tool to screen rice accessions for their susceptibility towards blast disease and that, based on a subset of markers, it is possible to predict the resistance to rice blast.

Straw is a valuable by-product from cereal production. It is used for agricultural purposes as feed and bedding material for livestock. Additionally, cereal straw is a resource for the production of sustainable biomaterials and bio-energy. To meet the demands of these sectors substantial amounts of straw, with specific properties (e.g. water-holding capacity), are necessary. Since wheat breeding has mainly focused on grain yield rather than on straw yield other cereal species, such as triticale, can be of interest. Therefore, in this research the straw yield and water-holding capacity of four winter wheat and four winter triticale varieties were studied during two growing seasons. For both wheat and triticale there were differences in dry matter yield and percentage dry matter between growing seasons. Furthermore, depending on the growing season, there were significant differences in straw yield between the different wheat and triticale varieties. However, during both growing seasons, the straw yield obtained from the triticale varieties was significantly higher compared to the straw yield obtained from the wheat varieties. Concerning the water-holding capacity, it was concluded that the water absorption potential of triticale straw was higher compared to the water absorption potential of wheat straw. However, only in 2014 a significant difference between wheat and triticale was noted. So, it can be concluded that, besides the known advantages of triticale (performance on marginal soils, disease resistance, low fertilizer input, etc.), this crop has the potential to deliver high yields of high quality straw.

To assess the early blight/brown spot (EB/BS) incidence in Flanders (Belgium), a survey was set up consisting of potato fields in 22 locations which were monitored and scored over the duration of the growing seasons 2014 and 2015. The survey demonstrated that the average disease incidence in 2014 was higher than in 2015. Soil type, rainfall and temperature were additionally analysed during the infection process. In 2014, potato plants grown in sandy soils had more EB/BS disease than those that were grown in clay or loamy soils. However, due to the low disease incidence, the difference in disease levels observed between different soil types in 2014 could not be repeated in 2015. A window-pane analysis demonstrated that rainfall and humidity account for the differences in disease incidence between the two growing seasons. During the course of the survey, the species composition in symptomatic leaves was assessed using real-time PCR. Remarkably, small-spored Alternaria species, such as A. alternata and A. arborescens, rather than the more virulent A. solani were the predominant species on potato leaves throughout the growing season. As the disease progressed, the share of A. solani increased. In view of these results, the virulence of a collected set of Alternaria isolates was assessed by an in vitro assay. Besides A. solani being more virulent than A. alternata or A. arborescens, the most abundant species isolated from symptomatic potato leaves was A. arborescens. This article is protected by copyright. All rights reserved.

Perennial ryegrass (Lolium perenne) is an important source of protein and energy for dairy cattle. To improve the protein/energy ratio of this forage, focus is now on improving its cell wall digestibility. The in vitro assessment of the digestible fraction of the neutral detergent fibre (NDFD) is a superior method for determining the cell wall digestibility, but requires the use of ruminal fluid, which has a highly variable composition and is often not readily available. As lignin is considered the main cell wall component that impedes NDFD, we investigated whether this “subtrait” could serve as alternative breeding selection criterion to improve NDFD. Therefore, we assessed the accuracy of two lignin quantification methods: van Soest (ADL) and Klason lignin (KL). We also considered KL estimates corrected for the solubilized lignin (total lignin or TL) and non-solubilized protein (TL'). Although the latter is considered the truest possible lignin content, it was not always the most correlated to NDFD, due to the limited accuracy of protein quantification on lignin residue. TL is most correlated to NDFD and we therefore recommend it for use in conventional breeding if NDFD determination is not a possibility. However, NDFD is still a superior selection criterion, as it combines the effect of several subtraits and not just lignin. For marker–trait association studies, a more accurate estimate of lignin content is more important than a high correlation with NDFD, but also here, TL performs best.

SUMMARYThe objective of the present study was to calculate an optimal harvest period for both fresh and ensiled samples of forage maize and to calculate a set of harvest dates (called a harvest window), for which the variety ranking of the fresh forage corresponds with the variety ranking at the optimal harvest period calculated from the ensiled forage. Forage maize is fed almost exclusively as silage, but official variety trials with silage maize determine quality parameters in fresh (i.e. non-preserved) forage. Eight silage maize varieties were monitored at six harvest dates (from 25 to 40% dry matter content) in Merelbeke (Belgium) in 2013–15. At each harvest date, fresh samples were taken and half of the sampled material was ensiled in micro silos for 20 weeks. An optimal harvest period was calculated based on frequently measuring starch concentration and organic matter digestibility for both fresh and ensiled forage. Eventually, harvesting the silage maize at a dry matter content of 32–35% guaranteed an optimal harvest period. Based on the results of eight varieties, reporting variety ranks without going through the ensiling process continues to be a scientifically justified practice in Belgian official variety trials. Varieties with a superior fresh quality keep their leading position after ensiling, but variety differences become smaller after ensiling.