Field Bean Research Articles

Testing the efficacy of Trichogramma ostriniae (Hymenoptera: Trichogrammatidae) as a inundative biological control agent in Western Nebraska.

The western bean cutworm (Striacosta albicosta) is a primary pest of corn and dry edible bean, for which control measures are often warranted. Inundative releases of Trichogramma ostriniae have been used to control lepidopterous pests, such as the European corn borer (Ostrinia nubilalis), in eastern North America (e.g., New York, Virginia). However, no prior field studies have assessed T. ostriniae as a biological control agent in the North American Great Plains. Objectives for this study were (i) to determine the suitability of S. albicosta as a host for T. ostriniae and (ii) to assess the feasibility of T. ostriniae as a biological control agent of S. albicosta in Nebraska corn and dry edible bean fields. Dispersal and parasitism were monitored with yellow sticky cards and sentinel egg masses (O. nubilalis, S. albicosta, and Ephestia kuehniella) at 36 locations surrounding a central release point. Trichogramma ostriniae adults tended to be concentrated near the point of release. However, egg parasitism was so low that the minimum rates of T. ostriniae needed for effective control could not be determined. Our evidence indicates that the low parasitism measured in this study may indicate low suitability of T. ostriniae to Western Nebraska and, possibly, the Great Plains.

Weed Communities of Snap Bean Fields in the United States

Abstract Weeds are one of the greatest challenges to snap bean production. Anecdotal observation posits certain species frequently escape the weed management system by the time of crop harvest, hereafter called residual weeds. The objectives of this work were to 1) quantify the residual weed community in snap bean (Phaseolus vulgaris L.) grown for processing across the major growing regions in the U.S., and 2) investigate linkages between the density of residual weeds and their contributions to weed canopy cover. In surveys of 358 fields across the Northwest (NW), Midwest (MW), and Northeast (NE), residual weeds were observed in 95% of the fields. While a total of 109 species or species-group were identified, one to three species dominated the residual weed community of individual fields in most cases. It was not uncommon to have >10 weeds m-2 with a weed canopy covering >5% of the field’s surface area. Some of the most abundant and problematic species or species-group escaping control included amaranth species (such as smooth pigweed (Amaranthus hybridus L.), Palmer amaranth (Amaranthus palmeri S. Watson), redroot pigweed (Amaranthus retroflexus L.), and waterhemp [Amaranthus tuberculatus (Moq.) J. D. Sauer]), common lambsquarters (Chenopodium album L.), large crabgrass [Digitaria sanguinalis (L.) Scop.], and ivyleaf morningglory (Ipomoea hederacea Jacq.). Emerging threats include hophornbeam copperleaf (Acalypha ostryifolia Riddell) in the MW and sharppoint fluvellin [Kickxia elatine (L.) Dumort.] in the NW. Beyond crop losses due to weed interference, the weed canopy at harvest poses a risk to contaminating snap bean products with foreign material. Random forest modeling predicts the residual weed canopy is dominated by common lambsquarters, large crabgrass, carpetweed (Mollugo verticillata L.), I. hederacea, amaranth species, and A. ostryifolia. This is the first quantitative report on the weed community escaping control in U.S. snap bean production.

Field Efficacy of Insecticide Molecules Against Pod Borer Complex in Vegetable Field Bean

Field Efficacy of Insecticide Molecules Against Pod Borer Complex in Vegetable Field Bean

Multispectral UAV Image Classification of Jimson Weed (Datura stramonium L.) in Common Bean (Phaseolus vulgaris L.)

Jimson weed (Datura stramonium L.) is a toxic weed that is occasionally found in fields with common bean (Phaseolus vulgaris L.) for the processing industry. Common bean growers are required to manually remove toxic weeds. If toxic weed plants remain, the standing crop will be rejected. Hence, the implementation of an automatic weed detection system aiding the farmers is badly needed. The overall goal of this study was to investigate if D. stramonium can be located in common bean fields using an unmanned aerial vehicle (UAV)-based ten-band multispectral camera. Therefore four objectives were defined: (I) assessing the spectral discriminative capacity between common bean and D. stramonium by the development and application of logistic regression models; (II) examining the influence of ground sampling distance (GSD) on model performance; and improving model generalization by (III) incorporating the use of vegetation indices and cumulative distribution function (CDF) matching and by (IV) combining spectral data from multiple common bean fields with the use of leave-one-group-out cross-validation (LOGO CV). Logistic regression models were created using data from fields at four different locations in Belgium. Based on the results, it was concluded that common bean and D. stramonium are separable based on multispectral information. A model trained and tested on the data of one location obtained a validation true positive rate and true negative rate of 99% and 95%, respectively. In this study, where D. stramonium had a mean plant size of 0.038 m2 (σ = 0.020), a GSD of 2.1 cm was found to be appropriate. However, the results proved to be location dependent as the model was not able to reliably distinguish D. stramonium in two other datasets. Finally, the use of a LOGO CV obtained the best results. Although small D. stramonium plants were still systematically overlooked and classified as common bean, the model was capable of detecting large D. stramonium plants on three of the four fields. This study emphasizes the variability in reflectance data among different common bean fields and the importance of an independent dataset to test model generalization.

Improving dual cover crop mixtures to increase shoot biomass production and weed suppression potential

IntroductionCover crop services depend on biomass production and species composition of the cover crop stand. In this study, we investigated the interactions in shoot biomass of dual cover crop mixtures and their competitiveness to suppress weeds before winter under different growing conditions.MethodsA field experiment was performed on sandy loam soil in Triesdorf, Germany, for two consecutive years. The cover crop species white mustard (Sinapis alba L.), oil radish (Raphanus sativus var. oleiformis L.), phacelia (Phacelia tanacetifolia J.), Egyptian clover (Trifolium alexandrinum L.), common vetch (Vicia sativa L.), field pea (Pisum sativum L.), and field bean (Vicia faba L.) were grown in pure stands or dual mixtures. Cover crops were sown in August, and shoot biomass was harvested at the end of the vegetation period. Cover crop shoot biomass was dried, and the share of each species and the sown test weed (Brassica napus L.) were determined.ResultsThe share of shoot biomass of a cover crop species in dual-species mixtures was closely related to its shoot biomass in its pure stand. In both years, mustard and phacelia showed similar interactions in shoot biomass production when growing with a second species. Regarding competitiveness against weeds, cruciferous species outperformed other cover crop species and could suppress weeds even if they were mixed with a less competitive partner. Weed suppression of mixtures with phacelia depended on the second component in the mixture and was more effective in a dry season. Legume species, especially Egyptian clover and common vetch could not suppress weeds in a pure stand.DiscussionOur results show that species with high weed suppression potential as single stands retain this ability in dual cover crop mixtures, regardless of the suppression potential of the second species that completes the mixture.

Assessment of crop suitability analysis using AHP-TOPSIS and geospatial techniques: A case study of Krishnagiri District, India

The cropped area of Krishnagiri district is about 37 % of the total geographical area, and due to the utilization of non-agricultural purposes (8.2% of agricultural land) it is mandatory to increase the agricultural production to feed the people. So, this study has been planned to find the agricultural suitability and crop suitability of the Krishnagiri district using AHP-TOPSIS and GIS techniques. In this study, three main limiting factors, such as climate, soil, and topographical parameters (Annual average rainfall, Annual average temperature, slope, pH, Electrical conductivity (EC), Soil organic carbon (SOC), available NPK, and soil texture), were used as criteria for the suitability of crops. All criteria maps were generated using Arc info 10.4 software. The AHP used to estimate the weight and TOPSIS (Technique for Order of Preference by Similarity to an Ideal Solution) approach was assign the rank of each criterion for the suitability analysis. Based on the relative closeness to the ideal solution(pi), the generated crop suitability maps were categorized into five classes, namely “highly suitable (S1), moderately suitable (S2), marginally suitable (S3), and not suitable (N)”. The results revealed that, crop suitability maps finds that that maize, field bean, cluster bean, groundnut, pomegranate, lemon, and lemongrass were highly suitable for the Krishnagiri district. Rice, cotton, sugarcane, sunflower, and cashewnut were moderately suitable, and vanilla was unsuitable. This study will guide farm managers and land policymakers in making decisions and assist farmers in selecting crops that are highly suitable for achieving potential yield and profit.

The impact of retrotransposons on castor bean genomes.

Castor bean (Ricinus communis L.) is an important oil crop. However, the influence of transposable elements (TEs) on the dynamics of castor bean evolution awaits further investigation. This study explored the role of transposable elements in the genomes of wild castor bean accessions from Ethiopia (Rc039) and Kenya (WT05) as well as in the cultivated variety (Hale). The distribution and composition of repeat sequences in these three lineages exhibited relative consistency, collectively accounting for an average of 36.7% of the genomic sequences. Most TE families displayed consistent lengths and compositions across these lineages. The dynamics of TEs significantly differed from those of genes, showing a lower correlation between the two. Additionally, the distribution of TEs on chromosomes showed an inverse trend compared to genes. Furthermore, Hale may have originated from the ancestor of Rc039. The divergent evolutionary paths of TEs compared to genes indicate the crucial role of TEs in shaping castor bean genetics and evolution, providing insights into the fields of castor bean and plant genomics research.

Intercropping maize (Zea mays L.) and field beans (Vicia faba L.) for forage, increases protein production

In 2005–2007, a field study was conducted into intercropping of maize with faba bean at Pawlowice research station, Wroclaw University of Environmental and Life Sciences. The main aim of the multi-year field research was an investigation into the reactions of differing maize hybrid earliness to intercropping cultivation with faba bean. The field research evaluated the effect of three maize hybrids—Wilga (early—E), Blask (medium—M) and Iman (late—L)—and the sowing rate of faba bean—18 (Fb1), 27 (Fb2) and 36 (Fb3) seeds per 1 m2—on growth dynamics and yield structure, and biomass, protein, and energy yield. Cultivation of faba bean in maize inter-rows led to significant competition with maize and affected yields, causing a decrease in maize dry matter yield from 14.1 (Fb1) to 20.6% (FB3) compared with maize sown alone. In terms of total biomass yield from maize and faba beans, no significant differences were found, but a slight increase in yield of 1.1–4.2% (repective to Fb1 and Fb3) was noted compared to maize sown alone. The early maize hybrid had a significantly lower yield but was most suitable for intercropping with faba bean. The dry biomass yield of early hybrids increased in intercropping by 25% compared to pure maize cultivation. Total protein yield from both intercropping components was higher than in the pure sowing of maize: from 24 (Fb1) to 39% (Fb3). The increase in protein production resulted in an improvement in the energy–protein ratio. The number of UFL per kg of total protein decreased from 13.2 in pure maize cultivation (M-P) to 9.3 (Fb3). A more balanced forage biomass was produced from intercropping maize with faba bean, especially when an early maize hybrid was sown with faba beans.

Growth, yield, quality and nutrient use efficiency of field bean as influence by planting geometry and nutrient levels

Growth, yield, quality and nutrient use efficiency of field bean as influence by planting geometry and nutrient levels

Occurrence, distribution, and genetic diversity of faba bean viruses in China.

With worldwide cultivation, the faba bean (Vicia faba L.) stands as one of the most vital cool-season legume crops, serving as a major component of food security. China leads global faba bean production in terms of both total planting area and yield, with major production hubs in Yunnan, Sichuan, Jiangsu, and Gansu provinces. The faba bean viruses have caused serious yield losses in these production areas, but previous researches have not comprehensively investigated this issue. In this study, we collected 287 faba bean samples over three consecutive years from eight provinces/municipalities of China. We employed small RNA sequencing, RT-PCR, DNA sequencing, and phylogenetic analysis to detect the presence of viruses and examine their incidence, distribution, and genetic diversity. We identified a total of nine distinct viruses: bean yellow mosaic virus (BYMV, Potyvirus), milk vetch dwarf virus (MDV, Nanovirus), vicia cryptic virus (VCV, Alphapartitivirus), bean common mosaic virus (BCMV, Potyvirus), beet western yellows virus (BWYV, Polerovirus), broad bean wilt virus (BBWV, Fabavirus), soybean mosaic virus (SMV, Potyvirus), pea seed-borne mosaic virus (PSbMV, Potyvirus), and cucumber mosaic virus (CMV, Cucumovirus). BYMV was the predominant virus found during our sampling, followed by MDV and VCV. This study marks the first reported detection of BCMV in Chinese faba bean fields. Except for several isolates from Gansu and Yunnan provinces, our sequence analysis revealed that the majority of BYMV isolates contain highly conserved nucleotide sequences of coat protein (CP). Amino acid sequence alignment indicates that there is a conserved NAG motif at the N-terminal region of BYMV CP, which is considered important for aphid transmission. Our findings not only highlight the presence and diversity of pathogenic viruses in Chinese faba bean production, but also provide target pathogens for future antiviral resource screening and a basis for antiviral breeding.

Using predatory species and entomopathogenic fungi as alternatives to chemical pesticides in green bean field

BackgroundGreen bean, Phaseolus vulgaris L. (Fam.: Leguminosae) is a widely consumed grain legume prized for its edible seeds and pods. It is susceptible to infestations with various pests as insects and mites throughout the growing season. In this study, the efficacy of the predatory species, Chrysoperla carnea (Stephens), Phytoseiulus persimilis Athias-Henriot and the entomopathogenic fungus (EPF) Metarhizium anisopliae (Hypocreales: Clavicipitaceae), as well as conventional pesticides, Mospilan and Vertimec, were evaluated against the most important pests, mainly the whitefly, Bemisia tabaci (Genn.) and the two-spotted spider mite, Tetranychus urticae Koch, infesting the green beans cultivated at two locations Giza and El-Menoufia Governorates in Egypt.ResultsThe findings demonstrate that treatments using C. carnea and M. anisopliae effectively reduced the whitefly population, while pesticide treatments were comparatively less effective. In the Giza plots, at the end of the experiments, the use of both M. anisopliae and C. carnea showed high reductions in whitefly population (85.57 and 84.87%), respectively, while in El-Menoufia, C. carnea (97.74%) was the most effective treatment followed by M. anisopliae (90.32%). Pesticide treatment in this case yielded a reduction rate of (22.76 and 59.67%) in Giza and El-Menoufia plots, respectively. However, for spider mite control, P. persimilis proved to be the most effective treatment in Giza and El-Menoufia plots, reducing the spider mite population to 98.44 and 96.14%, respectively. Metarhizium anisopliae treatment also displayed moderate effectiveness, with reduction rates of 75.62 and 75.37% in Giza and El-Menoufia plots, respectively. In comparison, pesticide treatment showed low effectiveness, with reduction rates of only 23.92 and 53.16% in the two locations, respectively.ConclusionApplications of the predator, C. carnea and the EPF, M. anisopliae were highly effective in reducing the population of whitefly, while the predator mite P. persimilis proved to be the most effective for controlling the spider mites. Overall, the study suggests that biocontrol agents, such as the predators and the EPF, can be considered as alternatives to synthetic chemical pesticides for controlling pests infesting green beans.

Can Nitrogen Fertilization and Intercropping Modify the Quality and Nutrient Yield of Barley–Field Bean Forage?

Can Nitrogen Fertilization and Intercropping Modify the Quality and Nutrient Yield of Barley–Field Bean Forage?

Detection of bean damage caused by Epilachna varivestis (Coleoptera: Coccinellidae) using drones, sensors, and image analysis.

The Mexican bean beetle, Epilachna varivestis Mulsant (Coleoptera: Coccinellidae), is a key pest of beans, and early detection of bean damage is crucial for the timely management of E. varivestis. This study was conducted to assess the feasibility of using drones and optical sensors to quantify the damage to field beans caused by E. varivestis. A total of 14 bean plots with various levels of defoliation were surveyed aerially with drones equipped with red-blue-green (RGB), multispectral, and thermal sensors at 2 to 20 m above the canopy of bean plots. Ground-validation sampling included harvesting entire bean plots and photographing individual leaves. Image analyses were used to quantify the amount of defoliation by E. varivestis feeding on both aerial images and ground-validation photos. Linear regression analysis was used to determine the relationship of bean defoliation by E. varivestis measured on aerial images with that found by the ground validation. The results of this study showed a significant positive relationship between bean damages assessed by ground validation and those by using RGB images and a significant negative relationship between the actual amount of bean defoliation and Normalized Difference Vegetation Index values. Thermal signatures associated with bean defoliation were not detected. Spatial analyses using geostatistics revealed the spatial dependency of bean defoliation by E. varivestis. These results suggest the potential use of RGB and multispectral sensors at flight altitudes of 2 to 6 m above the canopy for early detection and site-specific management of E. varivestis, thereby enhancing management efficiency.

Unravelling genetic diversity of whitefly species on different host plants from New Delhi

Aim: This study investigates the genetic diversity and distribution of different species of whiteflies on 20 host plants vegetables (cucumber, summer squash, pumpkin, tomato, brinjal, okra), field crops (sunflower, lettuce, field bean, lobia), commercial crops (cotton, tobacco), ornamentals (chrysanthemum, bellflower, marigold), fruit crops (lemon), trees (mulberry, wild tamarind, ficus), and others (wild brinjal) in New Delhi. Methodology: Genetic diversity was assessed through mitochondrial cytochrome oxidase-I gene-based molecular markers. Results: Phylogenetic analysis revealed that whitefly Bemisia tabaci was the most prevalent pest species across the crops reported in this study. The other whitefly species, viz., Dialeurodes sp., Singhiella simplex, Aleuroclava sp., Tetraleurodes acaciae, Trialeurodes vapororium, and Aleurodicus floccissimus were reported as pests of different horticultural crops. Interpretation: Genetic diversity of B. tabaci revealed that the genetic groups Asia II-1 and Asia II-7 were most prevalent, while Asia I was the minor one. Understanding the species composition and genetic diversity of whiteflies will help in devising appropriate control strategies. Key words: Hosts, Molecular markers, mtCOI, New Delhi, Phylogenetic analysis, Whitefly diversity

Morphological and molecular characterisation of Xylaria bifida a new species from French bean and corn fields of Jammu and Kashmir, India

Morphological and molecular characterisation of Xylaria bifida a new species from French bean and corn fields of Jammu and Kashmir, India

Molecular assessment of predation efficiency of Orius similis (Hemiptera: Anthocoridae) on Frankliniella occidentalis (Thysanoptera: Thripidae) and Tetranychus urticae (Acari: Tetranychida)

ABSTRACT The generalist predator Orius similis plays a crucial role in controlling the pests Frankliniella occidentalis (Pergande) and Tetranychus urticae Koch. To assess the effectiveness of O. similis in controlling these pests in bean field, we conducted field surveys and used DNA molecular analysis to quantitatively measure the levels of predation on each prey. Field surveys conducted from June 18 to August 7, 2021, showed a linear increase in the population densities of O. similis, F. occidentalis, and T. urticae. The population density of F. occidentalis and T. urticae peaked on July 16, whereas that of O. similis peaked on July 23. The highest positive rate for F. occidentalis and T. urticae was observed on July 23 and 16, respectively. The positive detection rate to F. occidentalis was significantly higher than that of T. urticae (t = 7.659, df = 14, P < 0.0001). The DNA half-lives of F. occidentalis and T. urticae were estimated at 4.44 and 2.60 h, respectively, based on the positive detection rates of both preys during the digestion time in O. similis. These results suggest that molecular intestinal content analysis can be effectively used to quantitatively evaluate the control effect of O. similis on F. occidentalis and T. urticae.

First report of Colletotrichum incanum causing leaf spots on common bean in Europe (Slovenia).

A Phaseolus vulgaris L. leaf showing necrotic spots was collected in an experimental bean field in central Slovenia in August 2021. The field contained diverse common bean lines sourced from genebank collections, with each line represented by 10 plants. While symptomatic leaves were seen across various lines, the reported species derived exclusively from a Huasca Huallaga Colorado plant (single-seed descent, USDA accession PI153714, doi: 10.18730/H7P9N), a Peruvian landrace. After incubating the leaf for 2 d at ambient temperature in a moist chamber, setose acervuli developed producing curved, distally tapering and proximately truncated conidia. Single-spore cultures developed equally-shaped conidia measuring 14.5-21.5 (avg. 18.5) × 3-4 (avg. 3.5) μm (n=60) on corn meal agar when mounted in lactic acid. Obtained morphological characters and sequences of the partial actin (GenBank accession, OR208162), beta-tubulin (OR208164), and histone 3 (OR208165) gene identified the isolate as Colletotrichum incanum H.-C. Yang, J.S. Haudenshield & G.L. Hartman. Sequences were identical to those from CBS 133485 (= NRRL 62592, IL6A), ex-type strain of C. incanum (KC110823, KC110814, and KC110796). Partial sequences of the chitin synthase (CHS) gene (OR208163), not available for the ex-type strain, was identical to sequences of other C. incanum strains reported from China (KP145539, ON189040, and OQ613679-OQ613686) or differed in two nucleotide positions (OL471268 and OL471269). The strain from Slovenia was deposited in the CBS biobanks of the Westerdijk Fungal Biodiversity Institute (Utrecht, The Netherlands) as CBS 150848. Pathogenicity of the strain was tested by spraying ca. 3×105 conidia as a watery spore suspension onto each leaf of 6 greenhouse-grown and 3 wk-old common bean plantlets (cv. KIS Amand). Nonsterile commercial substrate (Potgrond H, AGRO-FertiCrop) was used and natural light conditions at ambient temperatures (18-23°C) applied. Sterile water was sprayed on 6, equally grown negative control plants. Treated plants showed small brownish spots after 3 wks similar to those described by Yang et al. (2014) on soybean. Setose acervuli formed within 5 days after detached leaves were incubated in moist chambers. No acervuli formed on negative control plants. Conidia re-isolated from these acervuli and obtained cultures were morphologically identical to originally obtained conidia and cultures and those used for performing the pathogenicity test. Anthracnose is an important disease of common bean attributed to various races of C. lindemuthianum (Sacc. & Magnus) Briosi & Cavara (Nunes et al. 2021). Reporting an additional agent potentially able to cause diseases in common bean and so far not known to occur in Europe is of high relevance as the various genetic bean lines used in Europe may show alternative susceptibility levels to it. However, symptoms caused by C. incanum seem to be less severe as those caused by C. lindemuthianum and the species belongs to the C. spaethianum species complex, whose members have so far not been considered as pathogens of economic importance (Talhinhas & Baroncelli 2021). Yang et al. (2014) based C. incanum on isolates from soybean petioles (USA) and associated it with common bean by re-identifying strain ATCC 64682 obtained by Tu (1990) in Canada. Database queries revealed that it was encountered also on sugar beet (USA; Hanson et al. 2023) and on various crop hosts in China (e.g., chili; Diao et al. 2017), but not in Europe. The work was funded by the Ministry of Agriculture, Forestry and Food and conducted as part of research programs P4-0072 and P4-0431, financed by the Slovenian Research and Innovation Agency ARIS, and the Horizon 2020 project INCREASE funded by the European Union.

Assessment of Physicochemical Properties and Quality of the Breads Made from Organically Grown Wheat and Legumes.

This study aimed to explore the feasibility of substituting wheat flour with varying levels (10%, 15%, 20%, and 25%) of flour derived from field bean, chickpea, lentil, and pea seeds. The investigation focused on assessing the physical properties of wheat dough and the physicochemical characteristics of bread samples. The addition of legume seed flours significantly influenced the dough's development time, particularly with chickpea flour causing a notable increase in this parameter. While dough stability was generally shorter for mixtures containing wheat flour and legume seed flour, chickpea flour was an exception, significantly prolonging dough stability time. Furthermore, the inclusion of legume flours resulted in increased protein, ash, fiber, fat, and phenolic contents in the enriched bread, while the carbohydrate content decreased. Additionally, the crumb exhibited increased redness and yellowness and decreased lightness due to the enrichment of the bread. Notably, the antioxidant activity of bread containing legume flour also increased, with the most significant increase observed when pea flour was utilized. Conversely, negative effects on bread volume, crumb density, and texture parameters were noted with the incorporation of legume additives. Taking into consideration the results of both physicochemical analyses and sensory evaluation, it is recommended that the incorporation of the specified legume flours should not exceed 15% in relation to the quantity of wheat flour used.

Evaluation of Pigeonpea-based Intercropping System for Growth, Productivity, Economics, Available Nutrient and Nutrient Uptake under Alfisols

An experiment was conducted to the evaluation of pigeonpea-based intercropping system for growth, productivity, economics, available nutrient and nutrient uptake under alfisols of Karnataka during Kharif, 2020 at ‘K’ Block, Zonal Agricultural Research Station, University of Agricultural Sciences, Gandhi Krishi Vigyan Kendra, Bengaluru. The experiment had 15 treatments which were replicated thrice in Randomised Complete Block Design. Treatments consisted of sole crops pigeonpea and different intercrops mixed along with of intercrops (field bean, vegetable soybean and chia) in different row proportions of (1:2, 1:3 and 1:4).The study aimed to assess the growth, yield and economics of pigeonpea comprising planting geometry and different intercrops. The results indicated that the combined effect of paired-row pigeonpea with field bean at 120/60 cm × 30 cm (1:2) spacing recorded the highest seed yield (1770 kg/ha) and stalk yield (4026 kg/ha). Among planting geometry and intercropping systems, higher gross returns, net returns and B:C ratio (Rs. 2,60,591 ha-1, Rs. 2,19,030 ha-1 and 6.27 respectively) was recorded in T7 (paired row pigeonpea with vegetable soybean at 120/60 cm). Among planting geometry and intercropping system highest total nutrient uptake of pigeonpea was recorded in T6 (Paired row - 120/60 cm × 30 cm pigeonpea + field bean (1:2), 76.65, 12.20 and 98.36 kg/ha NPK respectively) compared to rest of intercropping treatments. In available nutrients, among planting geometry and intercropping systems highest total available nitrogen and phosphorous was recorded in T14: Sole vegetable soybean (318.62 and 107.20 kg/ha N &amp; P respectively) and higher total available potassium was recorded in T13: Sole field bean (321.40 kg/ha K respectively), compared to other treatments. The study concludes that the paired row pigeonpea with vegetable soybean at 120/60 cm x 30 cm yield and economics of the intercropping systems.

Predicting airborne ascospores of Sclerotinia sclerotiorum through machine learning and statistical methods

AbstractA main biological constraint of dry bean (Phaseolus vulgaris) production in Canada is white mould, caused by the fungal pathogen Sclerotinia sclerotiorum. The primary infectious propagules of S. sclerotiorum are airborne ascospores and monitoring the air for inoculum levels could help predict the severity of white mould in bean fields. Daily air samples were collected in commercial dry bean fields in Alberta, Manitoba and Ontario and ascospores were quantified using quantitative PCR. Daily weather data was obtained from in‐field weather stations. The number of ascospores on a given day was modelled using 63 different environmental variables and several modelling methods, both regression and classification approaches, were implemented with machine learning (ML) (random forests, logistic regression and support vector machines) and statistical (generalized linear models) approaches. Across all years and provinces, ascospores were most highly correlated with ascospore release from the previous day (r ranged from 0.15 to 0.6). This variable was also the only variable included in all models and had the greatest weight in all models. Models without this variable had much poorer performance than those with it. Correlations of ascospores with other environmental variables varied by province and sometimes by year. A comparison of ML and statistical models revealed that they both performed similarly, but that the statistical models were easier to interpret. However, the precise relationship between airborne ascospore levels and in‐field disease severity remains unclear, and spore sampling methods will require further development before they can be deployed as a disease management tool.