Systemic Fungicides Research Articles

Efficacy of Various Fungicides and Herbicides for the Management of Wheat Foot Rot Disease

The present research was conducted to investigate and assess the effectiveness of fungicides and herbicides in controlling the foot rot disease caused by the fungus Sclerotium rolfsii in wheat crops. Foot rot of wheat caused by Sclerotium rolfsii Sacc. has a major constraint and potential threat to successful wheat cultivation. Therefore affords were made to screen the different systemic, contact and combination of fungicides and herbicides in vitro condition against Sclerotium rolfsii. Different fungicides against S. rolfsii were tested in vitro. The efficacy of two systemic fungicides (Tricyclazole 75%W.P. & Carbendazim 50% WP); two non-systemic fungicides (Mancozeb 75%WP & Copper oxychloride 50% WP); one contact fungicides Propineb 70%WP and one combo fungicides (Metalaxyl 8%+Mancozeb 64%) were evaluated at different concentrations (50,150 and 250 ppm) on the development of S. rolfsii on Potato dextrose agar (PDA) medium using poisoned food technique. Among the six fungicides, Mancozeb was found best at all the concentrations followed by Tricyclazole at higher concentrations which inhibit the growth of S. rolfsii. Another method used for management strategy was herbicide for inhibiting the mycelial growth of S. Rolfsii. In vitro efficacy of selective herbicides viz. (Metribuzin 70% WP & Oxadiargyl 80% WP), systemic herbicide viz. (Pyrazosulfuron Ethyl 10% WP & Metsulfuron Methyl 20% WP) and one combo herbicides viz. (Bensulfuron Methyl 0.6% + Pretilachlor 6% GR) were tested at their recommended concentrations. Among them metribuzin showed 80.00 % growth inhibition, succeeded by Pyrazosulfuron ethyl (51.85%) and Bensulfuron methyl + Pretilachlor (45.92%).

Evaluation of Fungicides Against Rhizoctonia bataticola (Taub) Butler Causing Dry Root Rot of Groundnut and Their Compatability with Trichoderma asperellum

The efficacy of four systemic and combination fungicides, namely Carbendazim 12% + Mancozeb 63% WP, Tebuconazole 25% WG, Hexaconazole 4% + Zineb 68% WG, and Tebuconazole 50% + Trifloxystrobin 25% WG, against Rhizoctonia bataticola, the causal agent of dry root rot in groundnut was evaluated using the poison food technique. Among the tested fungicides, Hexaconazole 4% + Zineb 68% WG exhibited the highest efficacy, with 100% inhibition of mycelial growth at all concentrations tested. Tests of compatibility of these fungicides with Trichoderma asperellum revealed that Hexaconazole 4% + Zineb 68% WG caused 38.88% of growth inhibition in T. asperellum while the other fungicides tested were totally incompatible with100 percent inhibition.

Compatibility of indigenous <i>Trichoderma asperellum</i> with chemical fungicides for the management of chickpea wilt

Trichoderma asperellum is an antagonistic fungus, which has the ability to inhibit the growth of pathogens in target environment. The study on compatibility of T. asperellum with fungicide molecules was carried out to know its compatibility with different classes of fungicide molecules during the studies on antagonistic potential of Trichoderma sp. against Fusarium oxysporum f. sp. ciceris causing chickpea wilt. In the present study, each of six popular systemic, non-systemic and combi-fungicide molecules were used to study the compatibility with bioagent Trichoderma asperellum. The fungicides were used at three different concentrations, i.e., systemic fungicides at 0.05, 0.1 and 0.15 per cent and non-systemic and combi fungicides at 0.1, 0.2 and 0.3 per cent concentrations by using poisoned food technique. Among six systemic fungicides, only azoxystrobin was highly compatible, whereas other systemic fungicides were incompatible showing 100 per cent inhibition of T. asperellum. Among six non-systemic fungicides, propineb, copper oxychloride and copper hydroxide were compatible at all three concentrations tested. However, mancozeb was compatible at lower concentrations but incompatible at higher (0.3%) concentrations. Further, thiram and captan were highly incompatible. Among six combi fungicides, copper oxychloride + copper hydroxide and cymoxanil + mancozeb were compatible with T. asperellum.

Comparative Efficacy of Systemic and Combination Fungicides for the Control of Alternaria Leaf Spot of Cabbage

Alternaria leaf spot of cabbage, caused by the Alternaria brassicicola, affects leaves of cabbages and often results in head rots causing severe decline in yield. In this work, the effects of systemic and combination fungicides on A. brassicicola mycelia growth in vitro and disease severity in field trials were investigated. The results of in vitro evaluation revealed that both fungicides significantly inhibited (p < 0.05) the growth of A. brassicicola under in vitro conditions. However, metalaxyl-M 6% was less effective with 100 μg/mL having only 30 ± 3.5% inhibition. On the other hand, 100 μg/mL of mancozeb 63% + carbendazim 12% had 94 ± 3.5% growth inhibition of A. brassicicola, respectively, under the same conditions. Dose-response analysis of the efficacy of the two fungicides showed that the LC50 of metalaxyl-M 6% and mancozeb 63% + carbendazim 12% were 125.52 ppm and 57.22 ppm, respectively, indicating the superiority of combination fungicide over systemic fungicide alone. Field studies showed that while manure type significantly impacted on biomass production (p < 0.001), it did not significantly affect disease severity. On the other hand, the frequency of fungicide application impacted on disease severity, with biweekly application leading to a significant reduction in disease severity after 10 weeks.

Chemical Resistance of Diaporthe citri against Systemic Fungicides on Citrus.

Citrus melanose, caused by Diaporthe citri, has been one of the serious diseases, and chemical fungicides were used for protection in many citrus orchards of Jeju Island. Establishing a disinfectant resistance management system and reducing pesticide usage would be important for contributing to safe agricultural production. In this study, monitoring of chemical resistance was performed with 40 representative D. citri isolates from many citrus orchards in Jeju Island. Four different fungicides, kresoxim-methyl, benomyl, fluazinam, and prochloraz manganese, with seven different concentrations were tested in vitro by growing the mycelium of the fungal isolates on the artificial medium potato dextrose agar. Among the 40 fungal isolates, 12 isolates were investigated as resistant to kresoxim-methyl which could not inhibit the mycelium growth to more than 50%. Especially isolate NEL21-2 was also resistant against benomyl, whose hyphae grew well even on the highest chemical concentration. However, any chemical resistance of fungal isolates was found against neither fluazinam nor prochloraz manganese. On the other hand, in vivo bio-testing of some resistant isolates was performed against both kresoxim-methyl and benomyl on young citrus leaves. Typical melanose symptoms developed on the citrus leaves pre-treated with both agrochemicals after inoculation with the resistant isolates. However, no or less symptoms were observed when the susceptible isolates were inoculated. Based on these results, it was suggested that some resistant isolates of D. citri occurred against both systemic fungicides, which may be valuable to build a strategy for protecting citrus disease.

Efficacy of fungicides against Rhizoctonia solani (J. G. Kuhn) causing root rot of french bean

The present in vitro study was carried out at the Department of Plant Pathology, University of Agricultural Sciences, Dharwad, Karnataka, India to evaluate the efficacy of various fungicides against Rhizoctonia solani (J. G. Kuhn) causing root rot of french bean using poisoned food technique. Among the contact fungicides tested, captan (70.37 %) and chlorothalonil (69.63 %) recorded maximum percent inhibition of mycelial growth and significantly superior over all other treatments. Carbendazim, difenoconazole, hexaconazole, propiconazole and tebuconazole (systemic fungicides) recorded cent per cent inhibition of mycelial growth of Rhizoctonia solani. Cent percent mycelial inhibition was recorded in all the combi product fungicides viz., (carbendazim + mancozeb), (trifloxystrobin + tebuconazole), (tricyclazole + mancozeb), (captan 70 % + hexaconazole 5 %) and (carboxin + thiram) at all the concentrations.

Phosphonic acid in plant-based food and feed products – Where does it come from?

Salts of phosphonic acid (sodium or potassium phosphonate) or its ester fosetyl are highly effective systemic fungicides, which not only exhibit fungistatic activities, but also stimulate the natural defence systems of the plants against pathogens. Since EU legislation has approved potassium and sodium phosphonate as fungicides in 2013 and 2014, they are no longer permitted in organic agriculture. As a result, even minor contents of phosphonate in organic food samples are interpreted as an indication of a not permitted fungicide treatment. A maximum level of 0.01 mg/kg applies for food for infant nutrition. Here we present evidence from the scientific literature that phosphonate is also a natural compound, which occurs in significant amounts in the environment and is produced and consumed by microorganisms within the biogeochemical phosphorus cycle. Further potential sources for this chemical in the environment apart from agricultural fungicide applications are organophosphonates, as phosphonate occurs as a byproduct during their industrial production or during their microbial degradation in effluents from industry and households. An evaluation of Eurofins results from the analysis of phosphonate from 2017 to 2022 with methods achieving a limit of quantification (LOQ) of 0.01 mg/kg reveals that the compound was detected in 40.63% of all samples from organic and 43.42% from conventional agriculture, and in over 90% of organic samples of chickpeas, lentils, buckwheat, peanuts and wine. Furthermore, 97.3% of organic mushroom samples contain the compound and animal manure or compost used for cultivation is a potential source of the chemical. Consequently, other causes for phosphonate in food products than fungicide applications must be taken into account as well. Analysis of the ratio of the stable oxygen isotopes 18O and 16O was successfully applied to detect applications of mineral sulphur fertilizer in organic agriculture. Similarly, it might be also a promising tool to differentiate between phosphonate produced industrially and from natural sources.

MONITORING OF THE MAIN PATHOGENS FOUND IN APPLE PLANTATIONS AT SCDP IASI

The observations took place at RSFG Iasi, Development Center Falticeni in 2022, in apple plantations where a number of 9 phytosanitary treatments were applied to the warning, with the spray machine of the type Agroma. A total of 3 varieties (Jonathan, Golden delicious, Stakrimson) were studied compared to the untreated variant. The phytosanitary treatment program covered a wide range of phytopharmaceuticals, using 8 contact and systemic fungicides to prevent and combat pathogens that produce Venturia inaequalis, Erwinia amylovora,, Podosphaera leucotricha (Ell. et Ev) Salm and Monilinia laxa. Thus, in the untreated variant, the degree of attack for rapeseed on the fruit was 82.8%, and for Podosphaera leucotricha on the shoots the attack was 35% in the Jonathan variety. In the treated plot, the degree of Venturia inaequalis attack on fruit was reduced to 11.3% and 3.0% in the Starkrimson and Golden delicious varieties, and in the Jonathan variety up to 0.5%.

Development of a green liquid-phase microextraction procedure using a customized device for the comprehensive determination of legacy and current pesticides in distinct types of wine samples

In this work, we reported the development of a novel, simple, and green liquid-phase microextraction (LPME) procedure based on the use of a customized device for the determination of 47 multiclass pesticides in red, white, and rosè wine samples by GC-MS. The main parameters that affect the LPME were optimized using multivariate statistical techniques such as centroid-simplex mixture design and Doehlert design. The optimal conditions were: 70 μL of toluene as extractor solvent; concentration of NaCl (2.7%, m v−1); pH 4; and an extraction time of 30 min, under vortex-assisted agitation (at 500 rpm). After validation, it was possible to obtain LOQ values as low as 7.63 ng L−1 and extraction recoveries ranging from 81.7% to 119% for most of the target pesticides. The application of exploratory analysis, specifically Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA), provided evidence indicating contamination in the different types of wine samples, primarily by systemic fungicides.

Biotransformation of carbendazim in cowpea pickling process.

Carbendazim, a systemic fungicide, is one of the most commonly detected pesticides in cowpeas. Pickled cowpea is a fermented vegetable product with unique flavor favored in China. The dissipation and degradation of carbendazim were investigated in the pickled process. The degradation rate constant of carbendazim in pickled cowpeas was 0.9945 and the half-life of the carbendazim was 14.06±0.82 d. Seven transformation products (TPs) were identified in the pickled process. Furthermore, the toxicity of some TPs show more harmful to three aquatic organisms (TP134) and rats (all the identified TPs) than carbendazim. And most of the TPs posed more development toxicity and mutagenicity than carbendazim. 4 out of 7 TPs were discovered in the real pickled cowpea samples. These results shed light on the degradation and biotransformation of the carbendazim in the pickled process, to better understand the potential health risk of pickled food and evaluate the environmental pollution.

Determination of the Dissipation Dynamics and Terminal Residue of Bupirimate and Its Metabolites in Cucumber by QuEChERS-Based UPLC-MS/MS.

Bupirimate is widely used as a highly active systemic fungicide. However, the frequent and heavy use of bupirimate has led to pesticide residues in crops that threaten human health and food safety. At present, there is limited research on the detection of ethirimol, which is the metabolite of bupirimate. This study established an ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method to simultaneously detect bupirimate and ethirimol residues based on QuEChERS pretreatment. The average recoveries of bupirimate and ethirimol in cucumber were between 95.2 and 98.7%, respectively, with relative standard deviations (RSDs) of 0.92-5.54% at fortified levels of 0.01, 0.1, and 5 mg L-1. The established method was used to determine the residues in field trials in 12 regions of China, and the final residues of bupirimate were all less than the maximum residue limit (MRL). Since the risk quotient (RQ) of bupirimate and ethirimol in cucumber was less than 1.3%, the dietary risk assessment indicated that bupirimate and ethirimol had a low long-term dietary risk to the general population in China. This study provides effective guidance on the proper use of bupirimate in cucumber fields and a reference for establishing the MRL of bupirimate in China.

Bioefficacy of Lecanoric Acid Produced by Parmotrema austrosinense (Zahlbr.) Hale against Tea Fungal Pathogens

Lichens are symbiotic organisms that are composed of fungal partners and photosynthetic algal partners. During the symbiotic process in lichen thallus, the fungus synthesizes certain secondary metabolites in which lecanoric acid is very important in terms of antibiotic properties. Considering the vital importance of lecanoric acid, the present study aimed to produce lecanoric acid from the thallus of Parmotrema austrosinense lichen using Modified Bold’s basal salt medium and evaluate the bio-efficacy against tea fungal pathogens. Lecanoric acid was purified and confirmed by micro-crystallization method and subsequently bioassayed against tea fungal pathogens. The results revealed that lecanoric acid registered a significant antifungal activity in terms of the growth inhibition of test pathogens. Companion systemic and botanical fungicides were found to be inferior to lecanoric acid in the percentage of growth inhibition. The inhibition rate varied among tea pathogens. Of the tea pathogens tested, tea leaf disease-causing pathogens including Cercospora theae (C. theae), Glomerella cingulata (G. cingulate), and Phomopsis theae (P. theae) showed the highest percentage of growth inhibition followed by stem and root rot diseases. The present study suggests that lecanoric acid showed an inhibitory effect against tea pathogens, which might be due to antibiotic properties and fungicidal action of lecanoric acid.

Removal of Old Leaves and Soil Touching Unproductive Branches of Tea Bushes for Controlling Red Rust Disease in Bangladesh.

Only leaf reduction (Cultural measure), in treatment T4 [treated with leaf removal above 15 inches (38.10 cm) from ground level], maximum yield (2185.00 kgha-1) was found resulted 21.64% more over the control. T3 [10 inches (25.40 cm)] and T5 [20 inches (50.80 cm)] gave similar response having 20 and 20.68% increased yield over the control. The lowest severity (21.38 PDI) was found in T5 [20 inches (50.80 cm)] that was statistically identical to T4 [15 inches (38.10 cm)] and T3 [10 inches (25.40 cm)] having a decrease trend of 58.28%, 50.26% and 42.59% respectively. There is 92.99% impact of leaf reduction in reducing disease severity of red rust having a decrease trend of 7.2 PDI for removal of leaf by 5 inches (12.70 cm) from the soil level. Similarly there is 81.44% impact of leaf reduction in increasing yield of made tea (kg ha-1) having an increase trend of 103.01 unit for removal of leaf by 5 inches (12.70 cm) from the soil level. In leaf reduction (Cultural measure) with one round chemical application, treatment T13 [treated with leaf removal above 15 inches (38.10 cm) from ground level with one round of Carbendazim 50 WP] gave maximum yield (2,310.00 kgha-1) resulted 28.61% more over the control followed by T15 [20 inches (50.80 cm) with one round of Carbendazim 50 WP] and T14 [20 inches (50.80 cm) with one round of Copper-oxichloride 50 WP] having 28.18 and 27.69% increased yield of made tea. Lowest severity (9.63 PDI) was found in T15 [20 inches (50.80 cm) with one round of Carbendazim 50 WP] having 41.21% reduction over control followed by identical PDI in T12 [15 inches (38.10 cm) with one round of Copper-oxichloride 50 WP], T13 [15 inches (38.10 cm) with one round of Carbendazim 50 WP] and T14 [20 inches (50.80 cm) with one round of Copper-oxichloride 50 WP] having 77.40, 77.31 and 77.79% reduction respectively. There is 78.24% impact in reducing disease severity of red rust having a decrease trend of 2.23 PDI for removal of leaf by 5 inches (12.70 cm) from the soil level with one round chemical fungicide application. Similarly there is 51.76% impact in increasing yield of made tea (kg ha-1) having an increase trend of 30.21 unit for removal of leaf by 5 inches (12.70 cm) from the soil level with one round chemical fungicide. From the benefit cost analysis it is projected that the treatment T3 [10 inches (25.40 cm)] received the highest marginal rate of return (1202.17%) followed by 1152.17% in treatment T4 [treated with leaf removal above 15 inches (38.10 cm). One round of systemic fungicides like Carbendazim 50 WP with this cultural practice gave 1034.21% and 1091.42% marginal rate of return respectively. Considering yield of made tea, disease severity and benefit cost analysis viewpoint, it can be concluded that, the cost effective treatment is removal of soil touching old leaves attached with tea bushes of MSK and LSK pruned sections within 10 inches (25.40 cm) to 15 inches (38.10 cm) from the soil level.

Promising Combination Systemic Fungicides in Combating Basal Stem Rot Disease of Coconut

Basal stem rot disease is the most challenging disease in coconut crop, caused by Ganoderma lucidum. Combating the disease with new generation fungicides is a viable strategy for the promising disease control. Single and combination of new systemic fungicides in different commercial formulations were tested against the Ganoderma lucidum. Under in vitro study at 100, 250 and 500 ppm concentrations. The results revealed that Hexaconazole 4% + Carbendazim 16% SC, Hexaconazole 5% + Validamycin 2.5%SC and Azoxystrobin 11% + Tebuconazole 18.3% SC W/W were found superior in inhibiting the mycelial growth of Ganoderma as compared to other fungicides. Per cent inhibition indicated the effectiveness of potent fungicides against the pathogen even at lower concentration.

Evaluación de fungicidas utilizados en el manejo de Sigatoka negra en el cultivo de banano

The main phytosanitary problem of commercial bananas is black Sigatoka (BS; Mycosphaerella fijiensis), which causes damage to leaf area, loss of exportable quality, and low yields. The management of BS with mixtures of four systemic fungicides in different combinations in the border and central area of three banana plantations, and its effect on the severity of this disease were evaluated. The study was carried out in Ecuador, province of El Oro, Pasaje canton, at the ‘‘El Playón’’, ‘‘Mega Impulso’’ and ‘‘Lolita’’ farms; in an area of 5 hectares of the Williams cultivar with 10 years of production, 50 plants were selected in the vegetative phase in the borders and center of the plantation, four treatments were evaluated: T1 (Triazole+Amine), T2 (Pyrimethanil+Spiroxamine), T3 (Difenoconazole+Amine) and T4 (Amine+Pyrimethanil) and three replicates, with four applications every 14 days. Severity was assessed for 10 weeks using the Stover scale. The experimental design was a randomized block design and the data were analyzed by two-way ANOVA. The greatest fungicidal effect was achieved in ‘‘El Playón’’, the severity for leaf 4 in the border area was 37.5 % and 38 % in the center. On leaf 5, ‘‘El Playón’’ 55 %, ‘‘Mega Impulso’’ 60 %, and ‘‘Lolita’’ 72.5 % reached a severe value. The highest average number of functional leaves was obtained in ‘‘Mega Impulso’’ and the highest average number of old leaves free of streaks in ‘‘Lolita’’. The fungicides applied controlled BS, due to the low percentages of disease severity.

Importance of Dietary Uptake for in Situ Bioaccumulation of Systemic Fungicides Using Gammarus pulex as a Model Organism.

Bioaccumulation of organic contaminants from contaminated food sources might pose an underestimated risk toward shredding invertebrates. This assumption is substantiated by monitoring studies observing discrepancies of predicted tissue concentrations determined from laboratory-based experiments compared with measured concentrations of systemic pesticides in gammarids. To elucidate the role of dietary uptake in bioaccumulation, gammarids were exposed to leaf material from trees treated with a systemic fungicide mixture (azoxystrobin, cyprodinil, fluopyram, and tebuconazole), simulating leaves entering surface waters in autumn. Leaf concentrations, spatial distribution, and leaching behavior of fungicides were characterized using liquid chromatography coupled with high-resolution tandem mass spectrometry (LC-HRMS/MS) and matrix-assisted laser desorption ionization-mass spectrometric imaging. The contribution of leached fungicides and fungicides taken up from feeding was assessed by assembling caged (no access) and uncaged (access to leaves) gammarids. The fungicide dynamics in the test system were analyzed using LC-HRMS/MS and toxicokinetic modeling. In addition, a summer scenario was simulated where water was the initial source of contamination and leaves contaminated by sorption. The uptake, translocation, and biotransformation of systemic fungicides by trees were compound-dependent. Internal fungicide concentrations of gammarids with access to leaves were much higher than in caged gammarids of the autumn scenario, but the difference was minimal in the summer scenario. In food choice and dissectioning experiments gammarids did not avoid contaminated leaves and efficiently assimilated contaminants from leaves, indicating the relevance of this exposure pathway in the field. The present study demonstrates the potential impact of dietary uptake on in situ bioaccumulation for shredders in autumn, outside the main application period. The toxicokinetic parameters obtained facilitate modeling of environmental exposure scenarios. The uncovered significance of dietary uptake for detritivores warrants further consideration from scientific as well as regulatory perspectives. Environ Toxicol Chem 2023;00:1-14. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

A dual-state-emission chalcone-based supramolecular probe for ratiometric detection of penconazole in environmental samples

Penconazole (PEN) is a systemic triazole fungicide widely pulverized on fruits and vegetables to control powdery mildew disease. PEN has various hazardous effects on mammalians primarily through PEN-induced excessive generation of reactive oxygen species, which may cause metabolic disorders, cancer, etc. Therefore, development of an effective analytical method for PEN is of great importance for the environmental safety and human health. In the present work, we report a supramolecular fluorescent probe OPyCH@ALB constructed by selecting of a dual-state-emission chalcone as the indicator and albumin as the host, for the first time, successfully realizing the ratiometric detection of PEN. This probe is capable of detecting PEN with rapid response (10 s), high sensitivity (LOD = 0.28 μM, 76 ppb), high selectivity, and a visible fluorescence color change from green to red. Based on this probe, the portable paper-based test strips, which enable the on-site monitoring of PEN without the involvement of any complicated testing apparatus, were fabricated. Furthermore, this probe was used to realize the qualitative and quantitative analysis of PEN in ground water and soil with high accuracy, and successful achieved on-site recognition of PEN on the surface of grapes. We expect that this method will be applied as a convenient and affordable tool for the rapid monitoring of PEN at the point-of-use, such as in residential, agricultural, and food production settings.

Investigating the impact of fungicides and mungbean genotypes on the management of pod rot disease caused by Fusarium equiseti and Fusarium chlamydosporum.

Mungbean is a vital pulse crop in India that can thrive in dry-land conditions and is grown in three seasons, with the added benefit of being used as green manure due to its ability to fix atmospheric nitrogen. Recently, pod rot disease has emerged as a serious threat to mungbean cultivation in India. In this study, morpho-molecular identification of associated pathogens and the bio-efficacy of systemic and non-systemic fungicides as well as genotype screening was performed during the years 2019 and 2020. The pathogens associated with this disease were confirmed on the basis of morphological and molecular characterization. For the molecular characterization, the translation elongation factor 1-alpha (tef-1) gene sequences were amplified by using primers (EF1 and EF2). Under in vitro conditions, trifloxystrobin + tebuconazole 75% WG was found to be the most effective against Fusarium equiseti (ED50 2.39 μg ml-1) and Fusarium chlamydosporum (ED50 4.23 μg ml-1) causal agents of pod rot of mungbean. Under field conditions, three applications of trifloxystrobin + tebuconazole 75% WG at 0.07% as a foliar application at fortnightly intervals starting from the last week of July proved to be the most effective against pod rot disease on mungbean cultivars, i.e., ML 2056 and SML 668. To identify the potential resistance sources, 75 interspecific derivative and mutant lines of mungbean were screened for disease reaction to pod rot under natural epiphytotic conditions for the years 2019 and 2020. Genotypic differences were observed for resistance to pod rot disease. The study revealed that among the tested genotypes, ML 2524 exhibited resistance to pod rot disease, with a disease incidence of 15.62% and disease severity of 7.69%. In addition, 41 other genotypes were found to be moderately resistant (MR) to the disease. Altogether, the identified management options will offer an immediate solution to manage this disease under recent outbreak conditions and pave a path for futuristic disease management using identified resistant sources in breeding programs.

Gummy stem blight: One disease, three pathogens.

Gummy stem blight (GSB) is a major disease of cucurbits worldwide. It is caused by three fungal species that are morphologically identical and have overlapping geographic and host ranges. Controlling GSB is challenging due to the lack of resistant cultivars and the pathogens' significant ability to develop resistance to systemic fungicides. The causal agent of GSB is recognized as a complex of three phylogenetically distinct species belonging to domain Eukaryota, kingdom Fungi, phylum Ascomycota, subphylum Pezizomycotina, class Dothideomycetes, subclass Pleosporomycetida, order Pleosporales, family Didymellaceae, genus Stagonosporopsis, species cucurbitacearum, citrulli, and caricae. Pycnidia are tan with dark rings of cells around the ostiole measuring 120-180 μm in diameter. Conidia are 6-13 μm long, hyaline, cylindrical with round ends, and non- or monoseptate. Pseudothecia are black and globose in shape and have a diameter of 125-213 μm. Ascospores are 14-18 × 4-6 μm long, hyaline, ellipsoidal with round ends, and monoseptate with a distinct constriction at the septum. Eight ascospores are found per ascus. The upper end of the apical cell is pointed, whereas the lower end of the bottom cell is blunt. Species-specific PCR primers that can be used in a multiplex conventional PCR assay are available. The GSB species complex is pathogenic to 37 species of cucurbits from 21 different genera. S. cucurbitacearum and S. citrulli are specific to cucurbits, while S. caricae is also pathogenic to papaya and babaco-mirim (Vasconcellea monoica), a related fruit. Under favourable environmental conditions, symptoms can appear 3-12 days after spore germination. Leaf spots often start at the leaf margin or extend to the margins. Spots expand and coalesce, resulting in leaf blighting. Active lesions are typically water-soaked. Cankers are observed on crowns, main stems, and vines. Red to amber gummy exudates are often seen on the stems after cankers develop on cortical tissue.

Abamectin and difenoconazole monitoring in strawberry flowers and pollen sampled from Tetragonisca angustula (Latreille) (Hymenoptera: Apidae) hives located in crop vicinities

The increase in agricultural productivity associated with the emergence and the extensive use of pesticides is undeniable. However, strong evidence indicates that this continuous demand is causing serious environmental impacts and bringing toxic effects to associated biota as pollinating insects. The present work aims the determination of the insecticide abamectin (ABA) and the fungicide difenoconazole (DIF) in strawberry flowers (Fragaria x ananassa DUCH.) and pollen sampled from beehives of the stingless bee Tetragonisca angustula Latreille (Hymenoptera: Apidae) located nearby strawberry fields. For analysis, QuEChERS method was optimized, and the analytical performance of those two pesticides was verified. Then, the method was applied to strawberry flowers and the pollen was sampled during three field campaigns. While abamectin was not detected, the systemic fungicide difenoconazole was determined in almost all flowers and pollen samples, demonstrating the major persistence of this pesticide in investigated matrices. The results were then discussed about the difenoconazole application rate and transport to colonies to estimate a preliminary environmental risk assessment for stingless native bees. All calculations were proceeded considering exposure rates and toxicity data from the literature, adapted from Apis mellifera studies. In this sense, the determination, application, and discussion about risk assessment figure out as an important tool to the knowledge about the preliminary risks of native bees exposed to pesticides.