Fungicide Application Research Articles

Cytochrome c Oxidase Influences Pyraclostrobin Sensitivity in Fusarium graminearum by Regulating FgAox Through Transcription Factors FgAod2 and FgAod5.

Cytochrome c oxidase (Cox) is a crucial terminal oxidase in the electron transport chain. In this study, we generated 14 Cox gene deletion or overexpression mutants in Fusarium graminearum. Fungicide sensitivity tests revealed that 11 Cox gene deletion mutants displayed resistance to pyraclostrobin, while 10 overexpression mutants showed hypersensitivity. RNA-Seq and RT-qPCR analyses demonstrated the upregulation of FgAox (alternative oxidase in F. graminearum), FgAod2, and FgAod5 (alternative oxidase deficiency in F. graminearum) in ΔFgCox4-2 and ΔFgCox17-75 mutants. In 11 Cox gene deletion mutants, FgAox expression was significantly upregulated, whereas in 10 Cox gene overexpression mutants, it was significantly downregulated. FgAox overexpression mutants exhibit resistance to pyraclostrobin, while FgAox deletion mutants show hypersensitivity to pyraclostrobin. FgAod2 and FgAod5 were identified as transcription factors for FgAox. Our findings reveal that FgCox influences pyraclostrobin sensitivity by regulating FgAox through FgAod2 and FgAod5. Understanding pyraclostrobin resistance mechanisms in F. graminearum could help develop better fungicide rotation and application strategies to manage resistance and guide the creation of new fungicides targeting different pathways.

Phytoconstituent Profiling and Antifungal Efficacy of Artemisia absinthium L.: Towards Sustainable Bio-Fungicide Development.

Natural alternatives to synthetic fungicides are gaining prominence as the focus sharpens on developing protective products. In this regard, the present study aimed to discern the antifungal potential of Artemisia absinthium L., a traditional medicinal plant native to Kashmir, by identifying its key phytoconstituents. Here, we present the notable antifungal activity of the leaf extract of A. absinthium against Fusarium oxysporum, Penicillium digitatum, and Alternaria solani, as observed through in vitro tests. Further refinement of the extract through chromatography isolated fraction 4 (F4), unveiling 27 compounds with no prior literature on their occurrence in A. absinthium. Additionally, in silico molecular docking analysis revealed three compounds which include Bruceine B (1), Guanidine, (phenylmethyl)- (2) and Ethyl alpha-d-glucoside (3) as potent inhibitors of multiple target key fungal enzymes such as endopolygalacturonase, chitin deacetylase and 1, 3, 8-trihydroxynaphthalene. The virtual screening unveiled compounds 1-3 within fraction 4, displaying robust binding energy ranging from -8 to -5.8kcal/mol with multiple target enzymes. Notably, their efficacy surpassed that of the reference commercial fungicide, benodanil. This study underscores the burgeoning interest in harnessing natural alternatives for fungicidal applications, highlighting the potential of A. absinthium as a valuable resource in the quest for sustainable and effective bio-fungicides.

Sclerotinia sclerotiorum on bean and potato in Sinaloa: Etiology, epidemiology and alternatives for management

White mold (Sclerotinia sclerotiorum) is the main disease of bean and potato in Sinaloa. In the present review, the symptoms and signs of the disease as well as cultural and morphological characteristics of the teleomorph of the pathogen, its ecology and the epidemiology of the disease are addressed. The implementation of a prediction system which includes the carpogenic germination of the sclerotia and the phenology of both bean and potato for the management of the disease is described. This system considers soil temperature ranging from 13 to 19 °C a at depth of 2.5 cm in the soil and the flowering stage in both bean and potato to do the first spray application of synthetic fungicide to prevent the disease. In vitro studies indicated that Trichoderma harzianum, T. viride and T. atroviride reduced mycelial growth rate of S. sclerotiorum. The same antagonistic species exerted control of white mold under field conditions, where an increment of 40% of yield was observed in the treated plots, with respect to those treated with fungicide fluazinam. Future lines of research focusing on the ecology of the pathogen and management of the disease including the antagonistic fungi in the prediction system are suggested.

Targeted Chemical Strategies in Planting Holes: A Proactive Approach to Managing Phytophthora Crown Rot of Strawberry

Phytophthora crown rot (PhCR) of strawberry, most commonly caused by P. cactorum, is introduced in annual cropping systems on quiescently infected transplants. In Florida, preventative chemical treatments are applied through drip tapes promptly after plant establishment. Since strawberry plants are especially vulnerable to PhCR during the establishment period, delaying fungicide treatments can result in stand loss, reduced productivity and suboptimal fungicide efficacy. This project evaluated the effectiveness of applying Ridomil Gold® and Orondis® Gold directly to planting holes prior to transplanting. Results from trials over four growing seasons (2019–2024) demonstrated that fungicides applied in planting holes consistently reduced PhCR incidence and progression as effectively or more than products applied via drip. These findings suggest that direct in-hole fungicide application could be an alternative for managing PhCR in strawberry. These findings warrant further research into dosage and volume optimization, and the development of precision hole-punch applicators. Such technology could lead to more strategic fungicide use by placing the treatment only where needed, i.e. the root zone, and at the crucial timing of planting establishment. It also has the potential to improve disease control outcomes, enhance productivity, and reduce the need for further fungicide applications to control PhCR, thereby decreasing the risk of resistance development to key fungicides.

Impact of a new pesticide on rhizosphere microbes and plant health: case study of Y17991 against sharp eyespot in wheat

Sharp eyespot (Rhizoctonia cerealis) is a widespread soil-borne fungal disease that poses a severe threat to wheat health, and it is one of the main obstacles to achieving stable and high-quality wheat yields in China. Our collaborative team has developed a novel, efficient, and low-toxicity fungicide named Y17991 (N-(2-(2,4-bis-(trifluoromethyl)phenoxy)phenyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide). Preliminary laboratory tests confirmed the significant inhibitory effect of this agent on R. cerealis. Large-area field trials also demonstrated its efficacy, with a disease prevention index of 83.52%, which is 1.97% greater than that of the widely used thifluzamide, and it significantly increased the wheat yield. Moreover, this study explored the impacts of Y17991 on the structure and function of the microbial community in wheat rhizosphere soil. Bacterial communities were more strongly affected than fungal communities. Y17991 significantly modulated key amino acid metabolic pathways and certain biosynthetic processes in diseased wheat rhizospheres, and it also enhanced certain biosynthetic pathways and metabolic activities in healthy wheat rhizospheres. Additionally, the application of Y17991 regulated rhizosphere metabolites, thus exerting significant control over the microbial community. We identified 15 microbial strains potentially involved in the prevention and treatment of R. cerealis, and Y17991 treatment promoted the growth of Pedobacter and Bacillus strains. These strains not only aid in plant growth but they also have the potential for disease prevention. In summary, Y17991 application at a reasonable dose does not cause significant disruption to nontarget rhizosphere microbial communities. In future studies, we will continue to investigate the impacts of Y17991 on nonmicrobial components in soil ecosystems, such as protozoa and nematodes. Our research provides a theoretical basis for the scientific application and promotion of new fungicides and offers a significant reference for establishing a comprehensive system for assessing the ecological impact of pesticides on the environment.

Nighttime Applications of Germicidal UV Light to Suppress Cercospora Leaf Spot in Table Beet.

Cercospora leaf spot (CLS), caused by the hemibiotrophic fungus Cercospora beticola, is a destructive disease affecting table beet. Multiple applications of fungicides are needed to reduce epidemic progress to maintain foliar health and enable mechanized harvest. The sustainability of CLS control is threatened by the rapid development of fungicide resistance, the need to grow commercially acceptable yet CLS-susceptible cultivars, and the inability to manipulate agronomic conditions to mitigate disease risk. Nighttime applications of germicidal UV light (UV-C) have recently been used to suppress several plant diseases, notably those caused by ectoparasitic biotrophs such as powdery mildews. We evaluated the efficacy of nighttime applications of UV-C for suppression of CLS in table beet. In vitro lethality of UV-C to germinating conidia increased with increasing dose, with complete suppression at 1,000 J/m2. Greenhouse-grown table beet tolerated relatively high doses of UV-C without lethal effects despite some bronzing on the leaf blade. A UV-C dose >1,500 J/m2 resulted in phytotoxicity severities greater than 50%. UV-C exposure to ≤750 J/m2 resulted in negligible phytotoxicity. Older (6-week-old) greenhouse-grown plants were more susceptible to UV-C damage than younger (2- and 4-week-old) plants. Suppression of CLS by UV-C was greater when applied within 6 days of C. beticola inoculation than if delayed until 13 days after infection in greenhouse-grown plants. In field trials, there were significant linear relationships between UV-C dose and CLS control and phytotoxicity severity, and a significant negative linear relationship between phytotoxicity and CLS severity at the final assessment. Significant differences between UV-C doses on the severity of CLS and phytotoxicity indicated an efficacious dose near 800 J/m2. Collectively, these findings illustrate significant and substantial suppression by nighttime applications of UV-C for CLS control on table beet, with potential for incorporation in both conventional and organic table beet broadacre production systems.

Wheat genetic resources have avoided disease pandemics, improved food security, and reduced environmental footprints: A review of historical impacts and future opportunities.

The use of plant genetic resources (PGR)-wild relatives, landraces, and isolated breeding gene pools-has had substantial impacts on wheat breeding for resistance to biotic and abiotic stresses, while increasing nutritional value, end-use quality, and grain yield. In the Global South, post-Green Revolution genetic yield gains are generally achieved with minimal additional inputs. As a result, production has increased, and millions of hectares of natural ecosystems have been spared. Without PGR-derived disease resistance, fungicide use would have easily doubled, massively increasing selection pressure for fungicide resistance. It is estimated that in wheat, a billion liters of fungicide application have been avoided just since 2000. This review presents examples of successful use of PGR including the relentless battle against wheat rust epidemics/pandemics, defending against diseases that jump species barriers like blast, biofortification giving nutrient-dense varieties and the use of novel genetic variation for improving polygenic traits like climate resilience. Crop breeding genepools urgently need to be diversified to increase yields across a range of environments (>200 Mha globally), under less predictable weather and biotic stress pressure, while increasing input use efficiency. Given that the ~0.8 m PGR in wheat collections worldwide are relatively untapped and massive impacts of the tiny fraction studied, larger scale screenings and introgression promise solutions to emerging challenges, facilitated by advanced phenomic and genomic tools. The first translocations in wheat to modify rhizosphere microbiome interaction (reducing biological nitrification, reducing greenhouse gases, and increasing nitrogen use efficiency) is a landmark proof of concept. Phenomics and next-generation sequencing have already elucidated exotic haplotypes associated with biotic and complex abiotic traits now mainstreamed in breeding. Big data from decades of global yield trials can elucidate the benefits of PGR across environments. This kind of impact cannot be achieved without widescale sharing of germplasm and other breeding technologies through networks and public-private partnerships in a pre-competitive space.

Identification of Biomarkers Associated with Phyllosticta citricarpa Tolerance.

Citrus black spot (CBS) is a fungal disease caused by Phyllosticta citricarpa Kiely, (McAlpine Van der Aa), with most cultivars being susceptible to infection. Currently, disease control is based on the application of protective fungicides, which is restricted due to resistance, health and environmental concerns. Although using natural products for disease management is gaining momentum, more advances are required. This study obtained the metabolic profiles of the essential oil and cuticular waxes of two citrus cultivars with a varying susceptibility to CBS infection using gas chromatography-mass spectrometry. A multivariate data analysis identified possible biomarker compounds that contributed to the difference in susceptibility between the two cultivars. Several identified biomarkers were tested in vitro for their antifungal properties against P. citricarpa. Two biomarkers, propanoic acid and linalool, were able to completely inhibit pathogen growth at 750 mg/L and 2000 mg/L, respectively.

Effectiveness of Fludioxonil, a New-Generation Reduced-Risk Fungicide, Against Brown Rot Pathogens.

Brown rot, caused by Monilinia species, is a destructive disease of pome and stone fruits that can lead to significant losses in production. Disease management is mainly based on fungicide applications during the growing season. Fludioxonil, a "new-generation reduced-risk fungicide", is one of the most important fungicide used. The objectives of the present study were to compare and determine the toxicity of fludioxonil to selected M. laxa, M. fructigena and M. fructicola isolates, to test its effectiveness in detached fruits and to assess its effectiveness under practical control conditions. A total of 27 isolates (10 isolates of M. laxa, 8 of M. fructigena and 9 of M. fructicola) were tested for sensitivity to fludioxonil in vitro. Isolates from each species exhibited a homogeneous response to the fungicide, while differences among the different species were determined. Based on calculated resistance factors (RF), the examined isolates were classified into two categories: sensitive and moderately resistant. In vivo testing of the effectiveness of the label concentration of fludioxonil on detached fruit did not reveal differences between isolates classified into different sensitivity categories; fludioxonil used at the label concentration (0.1%) inhibited decay development 93.5 to 100%, regardless of the isolate category. Field trials revealed the very high efficacy of fludioxonil in preventing brown rot on fruits, ranging from 92.2 to 100 for peach, 90.7 to 97.3 for plum and 84.9 to 91.9% for sour cherry. In conclusion, fludioxonil was highly effective according to in vitro sensitivity tests and when used under practical field conditions for brown rot control.

Utilizing High-Resolution Imaging and Artificial Intelligence for Accurate Leaf Wetness Detection for the Strawberry Advisory System (SAS).

In strawberry cultivation, precise disease management is crucial for maximizing yields and reducing unnecessary fungicide use. Traditional methods for measuring leaf wetness duration (LWD), a critical factor in assessing the risk of fungal diseases such as botrytis fruit rot and anthracnose, have been reliant on sensors with known limitations in accuracy and reliability and difficulties with calibrating. To overcome these limitations, this study introduced an innovative algorithm for leaf wetness detection systems employing high-resolution imaging and deep learning technologies, including convolutional neural networks (CNNs). Implemented at the University of Florida's Plant Science Research and Education Unit (PSREU) in Citra, FL, USA, and expanded to three additional locations across Florida, USA, the system captured and analyzed images of a reference plate to accurately determine the wetness and, consequently, the LWD. The comparison of system outputs with manual observations across diverse environmental conditions demonstrated the enhanced accuracy and reliability of the artificial intelligence-driven approach. By integrating this system into the Strawberry Advisory System (SAS), this study provided an efficient solution to improve disease risk assessment and fungicide application strategies, promising significant economic benefits and sustainability advances in strawberry production.

Desempenho agronômico de genótipos de trigo em manejo de fungicidas

The aim of this work was to demonstrate the agronomic response of wheat genotypes to fungicide management. The experiment took place at Escola Fazenda of the Regional University of the Northwest of the State of Rio Grande do Sul, located in the municipality of Augusto Pestana, RS, Brazil. The experimental design used was randomized blocks, organized in a factorial scheme, with four fungicide managements (Management I: no application; Management II: one fungicide application; Management III: two fungicide applications and Management IV: three fungicide applications) x seven cultivars of wheat (TBIO Audaz, ORS Madre Pérola, BRS Bela Joia, TBIO Ponteiro, TBIO Trunfo, OR Agile, TBIO Toruk), in two replications. Three meters wide and five meters long formed the experimental units, totaling 15 m2 per plot. Evaluation of each plot, morphological and productive wheat traits. Use of Tukey's test at 5% probability for analysis of variance and linear correlation analysis to verify linear relationships between pairs of characters. Application of principal component analysis and euclidean distance to verify associations between treatments. The TBIO Trunfo cultivar enhances ear length with two fungicide applications. The management of fungicides did not influence the grain yield of wheat cultivars. The cultivars TBIO Trunfo and ORS Madre Pérola present the highest productive performance. Ear weight and number of grains per ear can select wheat cultivars with higher grain yield indirectly.

Improving detached tiller culture for doubled haploid production in wheat (T. aestivum L.) by post‐pollination fungicides application and UV radiation treatment

AbstractThis work aims at improving the proven protocol for doubled haploid production in wheat. This procedure has some deficits, for example, microbial infection of ears as well as of the nutrient culture medium. In the present study, the potential effect of sterilization by detached tiller culture fungicides of ears as well as of nutrient medium to control microbial infection, and its effect on the formation of caryopses and embryos (CFF, EFF) was studied. In a further experiment, the UV‐light was used as physical sterilant for the nutrient medium. All of the fungicides and their concentrations studied were found to be effective to control infection on ears except the concentration 0.05% tilt. 0.1% tilt gave the highest CFF (79.5%) followed by 0.1% Bayleton (78.0%). The lowest CFF was recorded in control treatment (48.8%). Among Bavistin treatments, the 0.2% Bavistin gave maximum CFF (68.5%) as well as EFF (29.1%) followed by 0.1% Bavistin (64.9%, 23.7%). The higher concentration of tilt (0.2%) showed detrimental effects on EFF (17.5%). Bavistin in tiller culture nutrient medium reduced infection in medium and was shown to improve CFF and EFF (67.4%, 29.8%).

Pesticide occurrence and distribution in fogwater collected at four sites at Strasbourg metropolitan between 2015 and 2021

The presence of pesticides in fogwater plays a major role in accumulating relatively substantial levels of trace compounds due to their unique physico-chemical characteristics. The radiation wintertime fog in Alsace has been studied in the past few years (between 2015 and 2021) at four sites (Geispolsheim, Erstein, Strasbourg, and Cronenbourg). Fog samples are extracted using the liquid-liquid extraction (LLE) performed on the XTR Chromabond cartridge coupled with gas/liquid chromatography-tandem mass spectrometry (GC-MS/MS and LC-MS/MS). The samples are found to be contaminated by 25 semi- and non-volatile currently-used and previously-banned pesticides (like procymidone) and 16 organochlorine pesticides (OCPs) at notable levels and high detection frequency (DF). The analysis also reveals that Cronenbourg is the most contaminated site (31.5 ± 3.0 μg. L−1), followed by Erstein (23.1 ± 17.0 μg. L−1), Strasbourg (23.0 ± 3.5 μg. L−1), and Geispolsheim (22.8 ± 7.7 μg. L−1). Pearson and principal component analyses (PCA) prove the simultaneous application of fungicides, insecticides, and herbicides, and their atmospheric transport, mainly through west-southern air currents, from highly impacted sites to near-by urban and less impact sites (Strasbourg and Cronenbourg). The levels of OCPs are found at lower concentrations at all sites than other pesticides, of which dichlorodiphenyltrichloroethane (DDT) and its metabolites have the highest contribution (27%), while hexachlorobenzene (HCB) has the least contribution (3%). Ratio analysis indicates the historical emission of DDTs, whereas a recent and local input of lindane and endosulfan has been observed.

UVC (254 nm) and Far UVC (222 nm) Irradiation Affects In Vitro Growth of Colletotrichum sp. Isolates and Their Infection of Detached Strawberry Leaves

Conventional ultraviolet C at 254 nm (UVC) and Far UVC at 222 nm (Far UVC) were evaluated as alternatives to fungicides for disease control. Conidia of 13 isolates of strawberry anthracnose pathogens (five Colletotrichum species in two complexes: C. acutatum and C. gloeosporioides) were uniformly dispersed onto agar and irradiated with UVC and Far UVC doses ranging from 52 to 1,248 J·m−2. After 48 h of incubation, a UVC dose of 1,248 J·m−2 and Far UVC doses from 234 to 935 J·m−2 reduced Colletotrichum colony counts to <10 colonies/Petri dish. Cultures exposed to UVC light followed by 4 h of darkness had lower colony counts than cultures incubated under continuous light. This dark incubation period was not required for Far UVC to obtain optimal lethality, indicating Far UVC irradiation can be applied during the day or night and achieve similar fungal lethality. Inoculation of detached leaves of three anthracnose-susceptible strawberry cultivars with conidial suspensions of Colletotrichum spp. revealed that UV irradiation can affect development of anthracnose symptoms. Leaves receiving UVC doses of 312 and 624 J·m−2 or a Far UVC dose of 467 J·m−2 reduced anthracnose infection with little or no plant injury. A UVC dose of 1,248 J·m−2 and Far UVC doses ≥ 467 J·m−2 inflicted varying degrees of plant injury. Disease control intended to reduce the number of fungicidal applications could be developed with moderate doses of UVC and Far UVC irradiation while slowing the evolution of pesticide-resistant strains. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 “No Rights Reserved” license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2024.

Effect of foliar fungicide application timing on corn yield across different water regimes

ABSTRACT Corn (Zea mays L.) is a major irrigated crop in the Texas High Plains (THP). Inadequate precipitation, declining groundwater resources, and inevitable seasonal drought in the area have led to a greater number of studies on crop hybrids, water regimes, and other yield-enhancing techniques. A four-year field study was conducted to investigate the effect of foliar fungicide timing on corn grain yield, grain moisture, and grain test weight under different irrigation regimes. A fungicide containing QoI + DMI was applied to four to six corn hybrids each year at various growth stages (V5, R1, and V5 + R1). For all years, corn plants were grown under three irrigation regimes to meet the seasonal evapotranspiration (ET) requirements of 50% (I50), 75% (I75), and 100% (I100). Hybrid response to the timing of fungicide application and irrigation regime was not consistent over the years. However, in 2 of the 4 years, timing of fungicide application resulted in yield differences among the hybrids, especially at I75 and L100. For those years, the fungicide applied at R1 resulted in a higher grain yield, grain moisture, and grain test weight followed by the fungicide applied at V5 + R1. Results showed that hybrids reacted differently to the foliar fungicide based on the availability of water under disease-free conditions. This study further revealed that irrigation water could be reduced from I100 to I75 with a limited (5.6% in 2011, 11.3% in 2012, 1.3% in 2013, and 0.3% in 2014) yield penalty in the THP region.

Over 50 years of a field experiment on cropping systems in Bałcyny, Poland: Assessing pesticide residues in soil and crops from the perspective of their field application history

Many agricultural problems can be illustrated and solved through long-term field experiments. Since 1967, an experiment has been conducted in Bałcyny, Poland, to compare continuous cropping with growing crops in crop rotation. The experiment also provides information on the history of chemical crop protection, which may have influenced soil and crop contamination with pesticide residues. In this study, fields of winter rye in continuous cropping (CCrye) and a 5–6-field crop rotation (CRrye) were used as an example to investigate the occurrence of pesticides in soil and grain in the context of previous use of chemical crop protection products. Two levels of crop protection were also examined: herbicide (since the 1972/73 growing season) and fungicide (since 1982/83) application (HF) and control treatment (CT; no herbicides since 1972/73, no fungicides since 1982/83). Insecticides were used only when absolutely necessary. Between 1967 and 2019, 58 different active substances were applied to the fields selected for this study. Soil and grain samples collected in 2019 after rye harvest were analyzed for the presence of 441 and 496 different substances, respectively. Only DDT and its metabolites were detected in soil, even though DDT was not applied to the fields after 1967. The concentration of ΣDDT (sum of all metabolites and isomers) ranged from 038 to 130 µg kg–1 soil and exceeded the limit set in Poland (120 µg kg–1) under CRrye-HF treatment. In winter rye grain, no pesticide residues were found. The results show that long-term rational use of less persistent pesticides does not lead to contamination of the soil or the test cereal grain, but DDT continues to threaten the environment five decades after its probable last use. The study points to the value of comprehensive long-term recording for providing a retrospective assessment of pesticide exposure. Long-term field experiments facilitate this approach.

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.

Profitability of foliar fungicides in double crop soybean under low-disease environments

Double-crop soybean production involves planting soybean (Glycine max) directly following winter wheat (Triticum aestivum) harvest. Frogeye leaf spot (FLS), caused by Cercospora sojina, is an important late-season foliar disease affecting soybean fields in the United States. In some instances, foliar fungicides have been used in double-crop soybean production with little to no FLS present, raising questions on the profitability of these applications. This study analyzed yield data from 25 fungicide trials across five states (Illinois, Indiana, Kentucky, Missouri, and Tennessee) conducted under low FLS pressure, from 2008 to 2021, on double-crop soybean. Fungicide classes evaluated in the trials included quinone outside inhibitors (QoI), demethylation inhibitors (DMI), and methyl benzimidazole carbamates (MBC) applied alone, and mixtures of chemistry classes that included DMI+succinate dehydrogenase inhibitor (SDHI), MBC+DMI, QoI+DMI, and QoI+DMI+SDHI. A network meta-analytic model estimated yield differences between fungicide-treated and nontreated plots, which ranged from -28 to 72 kg/ha among the fungicide treatments. Negative yield response values were estimated for the single fungicide classes MBC (-15.7 kg/ha) and QoI (-28.4 kg/ha). Yield difference as high as 72.8 kg/ha was estimated only for DMI+SDHI. Economic analyses indicated that, due to the lower yield responses, probabilities of breaking even were lower than 50% for all fungicide treatments, regardless of the fungicide cost or soybean sale price. Therefore, the low yield responses associated with foliar fungicides in low-disease environments linked to the higher risk of not offsetting the costs, suggest that growers should consider disease risk prior to making the fungicide application.

Network analyses predict major regulators of resistance to early blight disease complex in tomato

BackgroundEarly blight and brown leaf spot are often cited as the most problematic pathogens of tomato in many agricultural regions. Their causal agents are Alternaria spp., a genus of Ascomycota containing numerous necrotrophic pathogens. Breeding programs have yielded quantitatively resistant commercial cultivars, but fungicide application remains necessary to mitigate the yield losses. A major hindrance to resistance breeding is the complexity of the genetic determinants of resistance and susceptibility. In the absence of sufficiently resistant germplasm, we sequenced the transcriptomes of Heinz 1706 tomatoes treated with strongly virulent and weakly virulent isolates of Alternaria spp. 3 h post infection. We expanded existing functional gene annotations in tomato and using network statistics, we analyzed the transcriptional modules associated with defense and susceptibility.ResultsThe induced responses are very distinct. The weakly virulent isolate induced a defense response of calcium-signaling, hormone responses, and transcription factors. These defense-associated processes were found in a single transcriptional module alongside secondary metabolite biosynthesis genes, and other defense responses. Co-expression and gene regulatory networks independently predicted several D clade ethylene response factors to be early regulators of the defense transcriptional module, as well as other transcription factors both known and novel in pathogen defense, including several JA-associated genes. In contrast, the strongly virulent isolate elicited a much weaker response, and a separate transcriptional module bereft of hormone signaling.ConclusionsOur findings have predicted major defense regulators and several targets for downstream functional analyses. Combined with our improved gene functional annotation, they suggest that defense is achieved through induction of Alternaria-specific immune pathways, and susceptibility is mediated by modulating hormone responses. The implication of multiple specific clade D ethylene response factors and upregulation of JA-associated genes suggests that host defense in this pathosystem involves ethylene response factors to modulate jasmonic acid signaling.

Recent Advances in Design and Development of Diazole and Diazine Based Fungicides (2014-2023).

With fungal diseases posing a major threat to agricultural production, the application of fungicides to control related diseases is often considered necessary to ensure the world's food supply. The search for new bioactive agents has long been a priority in crop protection due to the continuous development of resistance against currently used types of active compounds. Heterocyclic compounds are an inseparable part of the core structures of numerous lead compounds, these rings constitute pharmacophores of a significant number of fungicides developed over the past decade by agrochemists. Among heterocycles, nitrogen-based compounds play an essential role. To date, diazole (imidazole and pyrazole) and diazine (pyrimidine, pyridazine, and pyrazine) derivatives make up an important series of synthetic fungicides. In recent years, many reports have been published on the design, synthesis, and study of the fungicidal activity of these scaffolds, but there was a lack of a comprehensive classified review on nitrogen-containing scaffolds. Regarding this issue, here we have reviewed the published articles on the fungicidal activity of the diazole and diazine families. In current review, we have classified the molecules synthesized so far based on the size of the ring.