Fungicide Combinations Research Articles

Ametoctradin + dimethomorph spray frequency affects late blight disease and yield in potato genotypes

AbstractPotato (Solanum tuberosum L.) production is hindered by several diseases, the worst being the late blight disease caused by Phytophthora infestans (Mont) de Bary. This study aimed at determining an appropriate frequency of ametoctradin + dimethomorph ([26.9 + 20.2]%) spray for late blight disease management in potato genotypes. Field experiments were conducted in Bansoa, Cameroon, from August to October in 2019 and 2020 growing seasons The experimental design was a split‐plot design with three replications. Three ametoctradin + dimethomorph spray frequencies (4‐, 7‐, and 10‐day intervals) were tested at the plot level, whereas seven genotypes including Banso, CIPIRA, Desiree, Dosa, Jacob2005, Manate, and Tezelfo were tested at the subplot level. The commonly used fungicide combination, which includes Mancozeb 80% wettable powder supplemented with cymoxanil + chlorotalomil [(30 + 6)%] wettable powder, was sprayed at 3‐day intervals (a total of 18 sprays) and was used as a positive control. Negative control plots were not sprayed. Data were collected on late blight rAUDPC (relative area under the disease progress curve) and yield components. Results showed all fungicide spray frequencies reduced rAUDPC and consequently increased potato yield. The most economically efficient spray frequency was the 7‐day interval with a total of nine sprays, which resulted in an increased net return of $9738 ha−1 with 9.6% profitability against the commonly used fungicide mix. The total number of fungicide sprays could be reduced to six for genotypes Banso and CIPIRA, which showed lower rAUDPC. The mean yield loss associated with unsprayed plots was 93.2%.

Investigating the Antagonistic Effects of Novel Combination Fungicides against Fusarium oxysporum f. sp. ricini under In-vitro Conditions

Aim: The study aimed to assess the efficacy of nine novel fungicide combinations against Fusarium oxysporum f. sp. ricini, the causal agent of wilt disease in castor. Methodology: The efficacy of fungicides was evaluated using the poisoned food technique under in-vitro conditions. Radial mycelial growth of the pathogen was measured across various concentrations (100 to 1000 ppm) of the fungicide combinations to determine their impact on mycelial inhibition. Results: Results indicated a substantial reduction in radial mycelial growth with increased fungicide concentration. Among the tested fungicides, Tebuconazole + Trifloxystrobin and Prochloraz + Tebuconazole recorded complete mycelial inhibition (100 %) at all the tested concentrations, demonstrating significant fungicidal activity followed by Hexaconazole + Captan with a mean mycelial inhibition of 85.2 %, indicating strong potential for disease management. In contrast, the least mean mycelial inhibition (24.7 %) was observed with Thiophanate methyl + Pyraclostrobin. Conclusion: These findings underscored the importance of selecting effective fungicide combinations to manage F. oxysporum f. sp. ricini, thereby enhancing crop protection and agricultural sustainability.

Phenolic Acids and Their Relationship to Nutritional and Technological Grain Parameters of Durum Wheat Under Variable Treatment Intensity in Central European Conditions

The objective of this two-year study was primarily the evaluation of the free and the bound forms of phenolic acids and phenolic aldehydes (PAAs) in grains of four selected cultivars of spring durum wheat subjected to three treatment intensities (GD—Green Deal, BT—Basic and IT—Intensive). All treatments included a common basic level and different spring production levels of nitrogen fertilisation (0 kg N in the case of GD; 30 kg N in the case of BT; and 60 kg N in the case of IT). Pesticide applications included herbicides and insecticides in both the BT and IT treatments, which were supplemented by combinations of fungicide and morphoregulator in the IT treatment. The GD treatment included only basic nitrogen, herbicide protection, and the application of a biostimulator (ExelGrow). The spring durum wheat cultivars subjected to testing were cultivated under Central European conditions, specifically in the Czech Republic’s central Bohemian region. UHPLC-ESI-MS/MS was used for the detection and accurate quantification of PAAs. In parallel, 12 other nutritional and basic technological parameters of the cereal were evaluated. Nine bound and seven free forms of PAAs were quantified in the analysed cereal samples. Bound forms of PAAs were dominant, accounting for 99.4% of total PAAs. Considering single PAAs, ferulic acid was the most abundant, accounting for 87% of the total bound PAAs. Interestingly, year and treatment intensity were the key factors in the variability of both free and bound PAAs, but these factors had different effects on bound PAAs. Under low nitrogen conditions, plants responded with an increase in free PAAs in particular, as well as in three bound PAAs. Unfavourable weather conditions, combined with the presence of biotic factors (e.g., Fusarium infections), significantly influenced the increase in both PAA groups, with the exception of free p-coumaric acid. PCA analysis confirmed close relationships between PAAs within both categories (free and bound). Subsequent correlation analysis further revealed that the immunoreactive gluten component (G12) exhibited a high negative correlation with the dominant ferulic acid (r = −0.70) and sinapic acid (r = −0.68). Additionally, moderate negative correlations were observed between four bound phenolic acids and grain hardness (r = −0.48–−0.60).

Unleashing the synergistic effect of promising fungicides: a breakthrough solution for combating powdery mildew in pea plants.

Pea powdery mildew, caused by Erysiphe pisi, is a major limitation to global pea production. The emergence of fungicide-resistant pathogen populations due to frequent and injudicious pesticide application highlights the importance of exploring the synergistic properties of fungicide combinations. This study investigated the efficacy of difenoconazole, thiophanate-methyl, and sulfur, both individually and in mixtures, against powdery mildew and assessed the interaction types between these fungicides. The results demonstrated that the combination of difenoconazole, thiophanate-methyl, and sulfur was the most effective in reducing, reducing disease severity to 6.10% and minimizing conidial production on foliage. Additionally, this fungicide combination reduced conidial germination by 89.26% in vitro and by 87.50% in a detached leaf assay compared to the control. The treatment also positively impacted leaf chlorophyll content (55.18), green pod yield (22.21 tons ha-1), seed yield (12.29 tons ha-1), and other yield-related parameters. Although statistically significant, this ternary fungicide combination was closely followed by the binary combination of thiophanate-methyl and sulfur, which was the only combination exhibiting synergism in both laboratory and field trials with a synergy factor (SF) > 1. In conclusion, this approach offers improved disease control as part of integrated disease management (IDM) while minimizing the risk of resistant pathogen strains.

Labor-saving application of thifluzamide and tricyclazole to seedling trays for integrated control of rice blast and sheath blight

Rice blast (Magnaporthe grisea) and sheath blight (Rhizoctonia solani) are limiting factors for rice production. Co-infection of these pathogens results in a disease complex which is difficult to control. In China, growers are accustomed to applying individual fungicides to manage blast and sheath blight, which require large amounts of labor. Application to seedling trays is a new promising solution for saving labor. In this study, application of combined fungicides with different modes of action to seedling trays to integrate control rice blast and sheath blight was evaluated in vitro assays and field trials. The results showed that the combination of thifluzamide and tricyclazole in the 1:2 ratio had significant synergistic inhibitory effects on the mycelial growth of M. grisea and R. solani, with a synergistic ratio (SR) of 2.17 and 1.49. Results from field trials revealed that thifluzamide + tricyclazole at 1107 and 958.5 g/ha applied to seedling trays was the most effective treatment to reduce the disease index of rice blast with control effects of 83.74–84.96% and 81.34–83.26% in 2022 and 2023, respectively, and no significant differences were observed from tricyclazole at 300 g/ha as foliar sprays twice. Compared to the untreated control, disease index of rice sheath blight was notably reduced by all treatments containing thifluzamide. The highest control was recorded in the treatment of thifluzamide + tricyclazole applied at 1107 g/ha to seedling trays. Moreover, compared to the untreated control, all treatments significantly enhanced rice grain yield by 7.67–17.86% and 3.38–18.91% in 2022 and 2023, respectively. The greatest yield (7429.73 and 7404.73 kg/ha in 2022 and 2023, respectively) was observed from the treatment of thifluzamide + tricyclazole at 1107 g/ha applied to seedling trays, with no significant differences among all the treatments containing tricyclazole. Taken together, these results indicated that seedling tray application of thifluzamide + tricyclazole could be a labor-saving approach to the integrated control of rice blast and sheath blight disease complex, while increasing rice grain yield.

Bioefficacy of propiconazole alone or in combination with other fungicides against Alternaria alternata causing leaf blight in cowpea

In the present study, the bioefficacy of propiconazole alone or in combination with other fungicides was evaluated for the management of Alternaria leaf blight in cowpeas under in vitro and field conditions. For this, propiconazole was employed in different fungicidal combination (viz., propiconazole 25 EC + chlorothalonil 75WP, propiconazole 25 EC + propineb 70 WP and propiconazole 25 EC + metiram 60 WG) with standard fungicidal check (viz., propiconazole 25 EC, tebuconazole 50 + trifloxystrobin 25 WG, pyraclostrobin 5 + metiram 55 WG and carbendazim 25 + mancozeb 50 WS) along with native isolate of Trichoderma spp. and untreated control. Among all fungicides, the mean colony diameter observed ranged from 0.00 to 31.68 mm at different concentrations of different fungicides with the mean growth inhibition ranging from 63 to 100%. The maximum 100% mean growth inhibition was recorded in propiconazole 25 EC, while a minimum 63% mean growth inhibition was recorded in carbendazim 25 + mancozeb 50 WS with 31.7 mm colony diameter under in-vitro condition. Among all the treatments, the highest reduction in disease incidence was observed in tebuconazole 50 + trifloxystrobin 25 WG with 71.6% disease reduction which was at par with propiconazole 25 EC + metiram 60 WG and propiconazole 25 EC + chlorothalonil 75WP with 70 and 62% disease reduction, respectively. The least effective treatment recorded pyraclostrobin 5 WG + metiram 55 WG with 33% disease reduction but effective over the control.

Chemical management strategies for halo blight of hop and in vitro sensitivity of Diaporthe humulicola populations to various fungicide classes.

Halo blight of hop, caused by Diaporthe humulicola, has increased in eastern North America since 2018. When left untreated, the disease can cause yield loss ranging from 17-56%. Currently, there are no fungicides registered for use on halo blight of hop. From 2020 to 2022 field trials were conducted using 10 fungicides registered for use on powdery and downy mildew of hop to determine their efficacy against halo blight. To validate field results, the EC50 value was determined for each active ingredient including flutriafol, tebuconazole + fluopyram, cyflufenamid, and trifloxystrobin + salicylhydroxamic acid (SHAM). Each fungicide tested had an EC50 value less than 50 ppm. A discriminatory dose was used to test the sensitivity of 206 D. humulicola isolates collected from the eastern U.S. and Canada in a poison agar assay. Results showed that tebuconazole + fluopyram decreased the incidence and severity of halo blight in the field. Also, this fungicide combination had EC50 values of 2.26 x 10-1 ppm and significantly reduced the growth of most of the isolates tested. Trifloxystrobin + SHAM decreased the presence of halo blight in the field tiral, but some isolates were less sensitive in discriminatory dose testing. Our results show that fungicides in FRAC groups 3, 7, and 11 were the most effective to control halo blight. Analyses of field trials showed a positive correlation between the severity of early season downy mildew infections and late season halo blight infections.

Potential Mechanisms of Hexaconazole Resistance in Fusarium graminearum.

Fusarium head blight (FHB) caused by Fusarium graminearum is a serious fungal disease that can dramatically impact wheat production. At present, disease control is mainly achieved by the use of chemical fungicides. Hexaconazole (IUPAC name: 2(2,4-dichlorophenyl)-1-(1,2,4-triazol-1-yl)hexan-2-ol) is a widely used triazole fungicide, but the sensitivity of F. graminearum to this compound has yet to be established. The current study found that the EC50 values of 83 field isolates of F. graminearum ranged between 0.06 and 4.33 μg/ml, with an average EC50 value of 0.78 μg/ml. Assessment of four hexaconazole-resistant laboratory mutants of F. graminearum revealed that their mycelial growth and pathogenicity were reduced compared with their parental isolates and that asexual reproduction was reduced by resistance to hexaconazole. Meanwhile, the mutants appeared to be more sensitive to abiotic stress associated with SDS and H2O2, while their tolerance to high concentrations of Congo red, and Na+ and K+ increased. Molecular analysis revealed numerous point mutations in the FgCYP51 target genes that resulted in amino acid substitutions, including L92P and N123S in FgCYP51A, as well as M331V, F62L, Q252R, A412V, and V488A in FgCYP51B, and S28L, S256A, V307A, D287G, and R515I in FgCYP51C, three of which (S28L, S256A, and V307A) were conserved in all of the resistant mutants. Furthermore, the expression of the FgCYP51 genes in resistant strains was found to be significantly (P < 0.05) reduced compared with their sensitive parental isolates. Positive cross-resistance was found between hexaconazole and metconazole and flutriafol, as well as with the diarylamine fungicide fluazinam, but not with propiconazole, and the phenylpyrrole fungicide fludioxonil, or with tebuconazole, which actually exhibited negative cross-resistance. These results provide valuable insight into resistant mechanisms to triazole fungicides in F. graminearum, as well as the appropriate selection of fungicide combinations for the control of FHB to ensure optimal wheat production.

New binary mixtures of fungicides against Macrophomina phaseolina: Machine learning-driven QSAR, read-across prediction, and molecular dynamics simulation

Quantitative Structure-Activity Relationship (QSAR) analysis greatly enhances the development and research of pesticides. This study employed Multiple Linear Regression (MLR), machine learning (ML), and read-across (RA) approaches to investigate the combined effects of binary mixtures of fungicides on Macrophomina phaseolina. Using the Fixed Ratio Ray Design (FRRD) method, 75 binary mixtures of six frequently used fungicides were generated, with many exhibiting additive interactions as indicated by the Concentration Addition (CA) and Independent Action (IA) models. The QSAR analysis revealed that Support Vector Regression (SVR) and Gaussian Process Regression (GPR) models were the most effective, outperforming the Least Squares Kernel (LSK), MLR, and RA methods. SVR achieved an outstanding R2 of 0.95 and Q2LMO of 0.81, whereas GPR demonstrated values of 0.93 and 0.81 for the same metrics. Internal and external validation confirmed the reliability and generalizability of these models, suggesting they could be applied to a wider array of data. Moreover, Molecular Dynamics (MD) simulations showed that the effects of the fungicides are linked to physiological mechanisms rather than intermolecular interactions within their formulations. This study establishes a robust framework for creating potent fungicide combinations that improve disease management efficacy while promoting environmental sustainability and reducing the chemical load to mitigate negative impacts.

Integrated Disease Management, Combining Chemical and Bio-control Agents, is Effective Against Agroathelia rolfsii Infecting Eggplants

The seeds of Guibourtia coleosperma serve as potential Agroathelia rolfsii severely infects 500 plant species causing stem and root rots on plants including eggplants. This study evaluated the compatibility of integration of chemical fungicides x biological agents for the management of recalcitrant disease agents like A. rolfsii. A factorial trial was set up using the completely randomized design with each treatment being replicated thrice. Interaction of Mancozeb (at 50 and 100% concentrations) x Trichoderma species caused 29.3-100% inhibition of A. rolfsii and Ketoconazole (at 50 and 100% concentrations) x Trichoderma species caused 95.8-100% inhibition of A. rolfsii. Mancozeb (100% concentration) x T. harzianum controlled the pathogen most, followed by the T. viride combination. The percentage inhibition by chemical fungicide (main effects) ranged from 100% inhibition by Ketoconazole (100% concentration) to 97.9-100% for Ketoconazole (50% concentration), to 65.2-93.6% for Mancozeb (100% concentration) and lastly 23.3-78.6% for Mancozeb (50% concentration) with time. The percentage inhibition (main effects) ranged from 60.3-96.7% for T. virens, 60.8-92.1% for T. harzianum, and 69.3-95.8% for T. viride with time. The chemical fungicides and Trichoderma species were highly positively correlated (0.522** at p ≤ 0.05). The high concentrations of the fungicides antagonized the Trichoderma species as well, so more work should be carried out on this aspect. This approach to disease management for eggplants is highly effective using chemical x bio-control agents to safeguard eggplants from A. rolfsii. Applying this method can protect crops and result in long-term profitability. The combination of fungicides and biocontrol agents is strongly recommended for the management of this fungal pathogen.

Status of Alternaria leaf blight in cotton and its fungicidal management

Surveys were carried out in the three districts of North Gujarat, viz., Aravalli, Sabarkantha, and Banaskantha to investigate the severity of Alternaria leaf blight in cotton, The disease was found to be quite severe and with a mean PDI of 23.77, the Banaskantha district had the highest disease intensity of Alternaria leaf spot disease; in contrast, the average disease intensity in the Aravalli and Sabarkantha districts was 17.94 and 20.44 per cent, respectively. Further, to manage the disease, research was conducted to evaluate the in vitro and in planta bioefficacy of fungicides against Alternaria macrospora of cotton at the Department of Plant Pathology and Alternaria leaf blight in cotton at Agronomy Instructional farm, S D Agricultural University Sardarkrushinagar, Gujarat, respectively. Under in vitro condition, among five systemic fungicides, Carbendazim showed the highest per cent growth inhibition, while Propiconazole showed the lowest. Among different non-systemic fungicides, Mancozeb inhibited the radial growth of A. macrospora the most, while Chlorothalonil inhibited the least. Further, among five combined fungicides, Tebuconazole 50% + Trifloxistrobin 25 WG inhibited the most growth and Captan 70% + Hexaconazole 50 WP inhibited the least. Thereafter, the bio-efficacy of the two most effective fungicides from each group (two systemic, two non-systemic, and two combined fungicides) was tested under field conditions, and the mean disease intensity ranged from 12.28 to 36.43 per cent, with the lowest being Tebuconazole 50% + Trifloxystrobin 25 WG and the highest being untreated control. The highest percentage of illness control (66.29%).. KEYWORDS :Alternaria macrospora, cotton, fungicides

Management of Fusarium Wilt of Castor (Ricinus communis L.) Caused by Fusarium oxysporum f.sp. Ricini with Biorationals and Fungicides under In vitro Conditions

To mitigate the harmful effects of synthetic chemical pesticides, eight biorationals i.e ginger, onion, bougainvillea, garlic, chili, turmeric, neem, and aloe vera were tested at different test concentrations of 10%, 15%, and 20% against Fusarium oxysporum f. sp. ricini, the pathogen causing wilt in castor. Among all the tested biorationas, chilli found as most effective while aloe vera showed the least pathogen suppression. The study recommended neem and chili as effective biorationals against F. oxysporum f. sp. ricini. New fungicide combinations i.e Picoxystrobin + Tricyclazole, Fluopyram + Tebuconazole, Boscalid + Pyraclostrobin, and Iprovalicarb + Propineb were tested under in vitro condition out of which Picoxystrobin + Tricyclazole and the standard fungicides Carbendazim and Thiophanate-methyl showed cent percent inhibition at all tested concentrations (500, 1000, 1500 and 2000 ppm). Fluopyram + Tebuconazole and Boscalid + Pyraclostrobin also showed high efficacy, while Iprovalicarb + Propineb was the least effective. The study revealed that neem and chili are recommended as effective biorationals against F. oxysporum f. sp. ricini. Among fungicides, Picoxystrobin + Tricyclazole proved most effective, suggesting its potential for managing castor wilt.

Management of Sunflower Powdery Mildew and Alternariaster Leaf Spot: Harnessing the Potential of Combined New Fungicide Molecules

The study investigates the efficacy of seed treatment with Fluxapyroxad FS @ 1.5 g/kg seed followed by foliar sprays of various fungicide combinations in managing powdery mildew and Alternariaster leaf spot diseases in sunflower. Conducted over three Kharif seasons (2021-2023), the trials consistently demonstrated the superior performance of Fluopyram 17.7% + Tebuconazole 17.7% (400 SC) @ 1 ml/L in reducing disease incidence and severity. In Kharif 2021, this treatment recorded the lowest incidence of Alternariaster leaf spot (7.36%) and powdery mildew (4.52%), outperforming other treatments. Similar trends were observed in Kharif 2022 and 2023, with Fluopyram + Tebuconazole maintaining the lowest disease severities (7.39% and 2.95% for powdery mildew, respectively). Notably, the study found no significant differences in yield components across treatments, though the highest yields were consistently recorded in the treatment combining Fluxapyroxad seed treatment with Fluopyram + Tebuconazole foliar spray, achieving yields of 2124.67 kg/ha in Kharif 2022 and 2157.33 kg/ha in Kharif 2023. These results indicate that integrated disease management using these fungicide combinations can effectively control both diseases in sunflower, particularly under humid weather conditions, without adversely affecting crop yield.

Effectiveness of Different Fungicides in Combating Tomato Powdery Mildew in Karnataka

Field experiment was carried out to know the effect of different fungicides against powdery mildew of tomato during two Kharif seasons of the year 2022 and 2023. Among the nine treatments, combination fungicides were significantly (p&lt;0.05) more effective than solo fungicides. Picoxystrobin 6.78% + Tricyclazole 20.33% SC applied at 2 ml/l achieved the lowest percent disease index (PDI) of 14% in the first season, with a 74.77% reduction over the control (55.50% PDI). This was closely followed by Azoxystrobin 18.2% + Difenoconazole 11.4% SC at 1.2 ml/l, which recorded a PDI of 14.50% and a 73.87% reduction. In the second season, similar trends were observed with Picoxystrobin 6.78% + Tricyclazole 20.33% SC achieving a PDI of 13.50% and a 74.53% reduction, followed by Azoxystrobin 18.2% + Difenoconazole 11.4% SC with a PDI of 14% and a 73.58% reduction. Pooled data from both seasons confirmed these findings, showing Picoxystrobin 6.78% + Tricyclazole 20.33% SC with a PDI of 13.75% and a 74.65% reduction, and Azoxystrobin 18.2% + Difenoconazole 11.4% SC with a PDI of 14.25% and a 73.73% reduction. The highest PDIs were noted in the Carbendazim 50% WP and Hexaconazole 5% SC treatments. The study highlights the inefficacy of relying on a single fungicide due to resistance development, suggesting combination fungicides as a more effective strategy for managing powdery mildew in tomatoes. It is possible advancing with broader integrated disease sustainable management strategies to protection of environment, crop protection and yield.

The neonicotinoid acetamiprid reduces larval and adult survival in honeybees (Apis mellifera) and interacts with a fungicide mixture

Plant protection products (PPPs), which are frequently used in agriculture, can be major stressors for honeybees. They have been found abundantly in the beehive, particularly in pollen. Few studies have analysed effects on honeybee larvae, and little is known about effects of insecticide-fungicide-mixtures, although this is a highly realistic exposure scenario. We asked whether the combination of a frequently used insecticide and fungicides would affect developing bees. Honeybee larvae (Apis mellifera carnica) were reared in vitro on larval diets containing different PPPs at two concentrations, derived from residues found in pollen. We used the neonicotinoid acetamiprid, the combined fungicides boscalid/dimoxystrobin and the mixture of all three substances. Mortality was assessed at larval, pupal, and adult stages, and the size and weight of newly emerged bees were measured. The insecticide treatment in higher concentrations significantly reduced larval and adult survival. Interestingly, survival was not affected by the high concentrated insecticide-fungicides-mixture. However, negative synergistic effects on adult survival were caused by the low concentrated insecticide-fungicides-mixture, which had no effect when applied alone. The lower concentrated combined fungicides led to significantly lighter adult bees, although the survival was unaffected. Our results suggest that environmental relevant concentrations can be harmful to honeybees. To fully understand the interaction of different PPPs, more combinations and concentrations should be studied in social and solitary bees with possibly different sensitivities.

Screening of Castor Germplasm and Efficacy Studies of Bioagents and Fungicides Against Botryotinia ricini (Godfrey) Whetzel

Castor is an important non-edible oilseed crop having exceptional oil characteristics for the chemical industry. The crop hosts several diseases, among them gray mold is the most destructive one hindering its productivity. This article presents a study assessing the resistance of different germplasm lines screened against Botrytis ricini under artificial conditions. It also examines the effect of various fungicides on B. ricini isolates, which were obtained from infected Ricinus communis (castor oil plant) using standard tissue isolation techniques. The fungus was isolated from infected Castor raceme by standard tissue isolation technique and its pathogenicity was established by proving Koch’s postulates. Out of 47 germplasm lines screened, TSIL-19 showed resistance response to gray mold under both detached spike and capsule method. Under in vitro assessment, Trichoderma viride (86.11 %) and Pseudomonas fluorescens (71.48 %) bio agents exhibited maximum mycelial growth inhibition of the pathogen. Among the seven combination fungicides evaluated, Fenamidone 10% + Mancozeb 50% WG recorded highest mycelial growth inhibition (100%) of B. ricini.

Rhizobium Inoculant and Seed-Applied Fungicide Effects Improve the Drought Tolerance of Soybean Plants as an Effective Agroecological Solution under Climate Change Conditions.

Rhizobial inoculation in combination with fungicidal seed treatment is an effective solution for improving soybean resistance to modern climate changes due to the maximum implementation of the plant's stress-protective antioxidant properties and their nitrogen-fixing potential, which will contribute to the preservation of the environment. Model ecosystems at different stages of legume-rhizobial symbiosis formation, created by treatment before sowing soybean seeds with a fungicide (fludioxonil, 25 g/L) and inoculation with an active strain of Bradyrhizobium japonicum (titer 109 cells per mL), were subjected to microbiological, biochemical, and physiological testing methods in controlled and field conditions. Seed treatment with fungicide and rhizobia showed different patterns in the dynamics of key antioxidant enzymes in soybean nodules under drought conditions. Superoxide dismutase activity increased by 32.7% under moderate stress, while catalase increased by 90.6% under long-term stress. An increase in the antioxidant enzyme activity induced the regulation of lipoperoxidation processes during drought and after the restoration of irrigation. Regeneration after stress was evident in soybean plants with a combination of fungicide seed treatment and rhizobial inoculant, where enzyme levels and lipoperoxidation processes returned to control plant levels. Applying seed treatment with fungicide and Rhizobium led to the preservation of the symbiotic apparatus functioning in drought conditions. As proof of this, molecular nitrogen fixation by nodules has a higher efficiency of 25.6% compared to soybeans without fungicide treatment. In the field, fungicidal treatment of seeds in a complex with rhizobia inoculant induced prolongation of the symbiotic apparatus functioning in the reproductive period of soybean ontogenesis. This positively affected the nitrogen-fixing activity of soybeans during the pod formation stage by more than 71.7%, as well as increasing soybean yield by 12.7% in the field. The application of Rhizobium inoculant and fungicide to seeds contributed to the development of antioxidant protection of soybean plants during droughts due to the activation of key enzymatic complexes and regulation of lipoperoxidation processes, which have a positive effect on nitrogen fixation and productivity of soybeans. This is a necessary element in soybean agrotechnologies to improve plant adaptation and resilience in the context of modern climate change.

Field efficacy of novel fungicides against chickpea rust (Uromyces ciceris-arietini)

The host resistance in present-day chickpea cultivars against rust disease is lacking thus, the present study was carried out during the winter (rabi) seasons of 2019–20 and 2020–21 at Regional Research Station, ICAR-Indian Institute of Pulses Research, Dharwad, Karnataka to explore effective fungicides for the management of chickpea rust. All fungicides found to reduce chickpea rust severity, but differences in efficacy were observed throughout the study. Present studies revealed that two sprays of 0.1% azoxystrobin 18.2% + difenoconazole 11.4% sc fungicide at 15 days interval minimizes the rust severity to the tune of &gt;77% and achieved a benefit cost (B:C) ratio of 2.32 i.e. in terms of monetary value farmers could get a net income of ₹35268/ha. Thus, timely spraying of identified modern fungicide combination can be taken advantage for better control of chickpea rust.

Quality assessment of soybean seeds submitted to industrial seed treatment and stored in a natural and controlled environment

Seed quality is a limiting factor in the search for high soybean yields. However, fungi and insect pests can negatively interfere with their performance, and industrial seed treatment (IST) is a tool used to minimize the attack of pathogens and pests. The treated seeds are often stored until sowing, which can lead to a reduction in their quality. This work aimed to evaluate the physical and physiological quality of soybean seeds submitted to IST, with subsequent storage in a natural and controlled environment. The experiment was conducted in a split-split-plot design in a completely randomized scheme (time x storage systems x IST) with four replications. Soybean cultivar 55I57RSF IPRO was subjected to IST with fungicide (metalaxyl-M, thiabendazole, and fludioxonil) and insecticide (thiamethoxam and cyantraniliprole), combined or not with polymer and dry powder, with subsequent storage in a controlled and natural environment. The moisture content, thousand-seed weights, germination, first germination count, germination speed index, accelerated aging, seedling length, dry matter transfer, and emergence sand test were evaluated. IST did not affect the moisture content and weight of a thousand seeds. However, storage in a controlled environment provided a greater reduction in moisture content and a smaller reduction in the weight of a thousand seeds. IST negatively affected germination, first germination count, germination speed index, and accelerated aging test. IST negatively affected plant length, except in the treatment where only insecticide was applied. The dry mass transfer was negatively affected but with less intensity in seeds subjected only to the application of insecticide or fungicide and the combination of insecticide, fungicide, and polymer. Seed emergence in the sand was negatively affected by all treatments. Regardless of the treatments, all responses evaluated showed a reduction throughout storage, with greater intensity in seeds stored in the natural environment.

Chemical management of Phakopsora pachyrhizi: Effect on incidence, severity, and yield in soybean

Asian soybean rust (Phakopsora pachyrhizi) is one of the main diseases in soybean crops. In Mexico, there is limited knowledge regarding its management, therefore the objective of this research was to evaluate the effect of mixtures of fungicides of the families: Carboxamides, Strobilurins, and Triazoles on incidence, severity, fungicide efficiency, and yield in soybean variety ‘Huasteca 700’. Three commercial combinations of fungicides were evaluated: Tebuconazole + Trifloxystrobin, Fluxapyroxad + Pyraclostrobin, Cyproconazole + Azoxystrobin, with surfactant (Agrega®) at 0.1%, and a control which consisted only of surfactant. The highest incidence and severity occurred in the control treatment; fungicide application formulated with Strobilurins, and Triazoles significantly reduced incidence (54 to 98%) and severity (82 to 100%) and provided a crop protection period of 35 to 54 days post-application. The incidence and severity by stratum plant were lower in the second evaluation cycle, with respect the first evaluation. Damage remained below 1.24, 0.5, and 0.03% in the low, middle, and upper stratum, respectively in treatments treated with fungicides 56 days after the first application. With two applications of chemical fungicides formulated with Strobilurins and Triazoles, in a natural infestation of Asian soybean rust, the damage and incidence were significantly reduced compared to the control treatment.