Kresoxim Methyl Research Articles

Evaluating Alternative Fungicides for Effective Management of Rice Blast Disease: Inhibitory Effects on Pyricularia oryzae Cavara

Tricyclazole has been a successful solution for managing rice blast for over three decades. However, the continuous use of this fungicide has led to the development of resistance and the accumulation of tricyclazole residues within rice grains, prompting a ban on its usage in India. In response to this pressing issue, the present study aims to evaluate the efficacy of alternative fungicides in controlling the growth of Pyricularia oryzae, the causal agent of rice blast. The study employed a comprehensive approach, assessing the performance of various fungicides, including picoxystrobin, hexaconazole, isoprothiolane, kresoxim methyl, pyraclostrobin, tebuconazole, kitazin, and zineb, at varying dosage levels (100%, 75%, and 50% of the recommended dose). The findings of this investigation indicated that hexaconazole, isoprothiolane, kitazin, and zineb exhibited a 100% inhibition of P. oryzae growth across all tested doses. Pyraclostrobin also demonstrated a 100% inhibition at the highest dose, although its effectiveness decreased slightly at lower doses. In contrast, picoxystrobin and kresoxim methyl did not exhibit significant effectiveness in controlling the growth of the rice blast pathogen. These results provide valuable insights into the potential alternatives to tricyclazole for managing rice blast when used either alone or in combination at reduced doses.

Survey of Rice Sheath Blight Disease in Kuttanad and Effect of Biocontrol Agents and Fungicides against Rhizoctonia solani

Aims: Rice is an important crop cultivated worldwide, whose production is influenced by numerous factors like pest, disease, weather parameters. In India, diseases accounts for 35 per cent in yield reduction, with sheath blight being significant. This disease is notably prevalent in Kuttanad region of Kerala. This study involves a survey conducted in Kuttanad to assess the extent of the disease and in vitro management using biocontrol agents and fungicides. Study Design: Study was outlined in Completely Randomised Design (CRD) to evaluate the in vitro efficacy of bioagents. Place and Duration of Study: Department of Plant Pathology, College of Agriculture, Vellayani and M.S. Swaminathan Rice Research Station, Moncompu, between 2022 and 2023 Methodology: Survey was conducted in forty locations of Kuttanad in which the disease incidence was recorded and samples were collected. The isolates obtained were tested for pathogenicity by artificial inoculation on rice variety, Uma. Cultural characteristics of isolates were studied. The virulent culture obtained was further advanced for the in vitro studies with biocontrol agents and fungicides. The inhibition of fungal growth was also recorded. Results: Forty isolates of sheath blight pathogen (Rhizoctonia solani) were obtained. The virulent isolate among these was identified on the basis of number of days taken for symptom development by artificial inoculation and this was further advanced for the in vitro studies. Bacillus amyloliquefaciens was found to be more effective with an inhibition percentage of 68.64. Among the tested fungicides, Kresoxim methyl 40% + Hexaconazole 8% WG showed cent per cent growth inhibition of pathogen at 500 and 1000 ppm concentrations which was on par with Azoxystrobin 18.2% + Difenoconazole 11.4% SC at 1000 ppm. Conclusion: From this study, it can be concluded that, that these biocontrol agents and fungicides are very effective in the management of the pathogen and hence can be used for further field-level studies in management of the disease.

Evaluation of Fungicides against Fusarium pallidoroseum (Cooke) Sacc. causing Wilt of Coriander In vitro

Coriander (Coriandrum sativum L.) is one of the most important spice crop known to affect by various diseases. Among them, coriander wilt causes serious problems and it is also caused by a newly reported causal agent Fusarium pallidoroseum (Cooke) Sacc. Hence, F. pallidoroseum being new pathogen on coriander, a laboratory experiment was conducted to study the efficacy of different non-systemic fungicides at 1000, 1500 and 2000 ppm; systemic fungicides at 100, 250 and 500 ppm and ready-mix fungicides at 500, 750 and 1000 ppm concentrations against F. pallidoroseum using Poisoned Food Technique. The results revealed that, among non-systemic fungicides, copper oxychloride 50 WP at all concentration found significantly superior with cent per cent mycelial growth inhibition. In contrast, propineb 70 WP found least effective at 1000 ppm concentration (2.71%). Among systemic fungicides, flusilazole 40 EC and thiophanate methyl 70 WP each at 500 ppm concentration gave cent per cent mycelial growth inhibition of F. pallidoroseum. While, kresoxim methyl 44.3 SC found least effective at 100 and 250 ppm concentration (9.74 and 12.95%). Among ready-mix fungicides, prochloraz 5.7 + tebuconazole 1.4 ES at all concentration and azoxystrobin 18.2 + difenoconazole 11.4 SC at 1000 ppm concentration found effective and showed cent per cent mycelial growth inhibition of F. pallidoroseum. While, fluxapyroxad 25 + pyraclostrobin 25 SC at 500 ppm found least effective (18.34%).

Network analysis of toxic endpoints of fungicides in zebrafish

Abstract Zebrafish being the best animal model to study, every attempt has been made to decipher the toxic mechanism of every fungicide of usage and interest. It is important to understand the multiple targets of a toxicant to estimate the toxic potential in its totality. A total of 22 fungicides of different classes like amisulbrom, azoxystrobin, carbendazim, carboxin, chlorothalonil, difenoconazole, etridiazole, flusilazole, fluxapyroxad, hexaconazole, kresoxim methyl, mancozeb, myclobutanil, prochloraz, propiconazole, propineb, pyraclostrobin, tebuconazole, thiophanate-methyl, thiram, trifloxystrobin and ziram were reviewed and analyzed for their multiple explored targets in zebrafish. Toxic end points in zebrafish are highly informative when it comes to network analysis. They provide a window into the molecular and cellular pathways that are affected by a certain toxin. This can then be used to gain insights into the underlying mechanisms of toxicity and to draw conclusions on the potential of a particular compound to induce toxicity. This knowledge can then be used to inform decisions about drug development, environmental regulation, and other areas of research. In addition, the use of zebrafish toxic end points can also be used to better understand the effects of environmental pollutants on ecosystems. By understanding the pathways affected by a given toxin, researchers can determine how pollutants may interact with the environment and how this could lead to health or environmental impacts.

Efficacy of Novel Fungicides for the Management of false smut of Rice Caused by Ustilaginoidea virens

In the present investigation eight fungicides were tested against the false smut disease of rice during kharif-2016-19. Among the different fungicides evaluated, two sprays of Trifloxystrobin 25% + Tebuconazole 50% (75 WG) at 0.03 per cent (4 gm/10 l) and Propiconazole 25 EC at 0.025 per cent (10 ml/10 l.) applied at booting and post flowering stage were found effective for the management of false smut. The other effective fungicides were Mancozeb 75 WP, Tebuconazole 25.9 EC, Tricyclazole 75 WP, Kresoxim methyl 50 SC, Azoxystrobin 23 SC and Carbendazim 50 WP.

Aquatic photolysis of strobilurin fungicide kresoxim-methyl: kinetics, pathways, and effects of adjuvants

Investigations of fungicide kresoxim-methyl's phototransformation elucidated the kinetics, intermediates, pathways, and toxicological impacts, also emphasizing the modulation of adjuvants.

A study on the pesticides-loading capacity of dendritic fibrous nano silica synthesized from 1-pentanol-water microemulsion with a low oil-water ratio.

Dendritic fibrous nano silica (DFNS) represents an optimal carrier material for pesticide constituents, due to its radial accessibility channels and high specific surface area. A low-energy methodology for synthesizing DFNS at a low volume ratio of oil to water is provided by employing 1-pentanol as the oil solvent in the microemulsion synthesis system, renowned for its remarkable stability and exceptional solubility. The DFNS@KM nano-pesticide was fabricated using a diffusion supported loading (DiSupLo) method and kresoxim-methyl (KM) as the template drug. Findings from Fourier-transform infrared spectroscopy, XRD, thermogravimetric, differential thermal analysis, and Brunauer-Emmet-Teller analyzes revealed the physical adsorption of KM onto the synthesized DFNS without any chemical bonding, with KM mainly existing in an amorphous state within the channels. High-performance liquid chromatography measurements demonstrated that only the loading amount of DFNS@KM was primarily dependent on the KM to DFNS ratio, with minimal effects observed from loading temperature and time. The loading amount and encapsulation efficiency of DFNS@KM were found to be 63.09% and 84.12%, respectively. Furthermore, DFNS effectively prolonged the release of KM, with a cumulative release rate of 85.43% over 180 h. The successful loading of pesticide components into DFNS synthesized with a low oil-to-water ratio provides theoretical support for the industrialization of nano-pesticides, with significant implications for enhancing pesticide utilization, reducing pesticide dosage, augmenting agricultural efficiency, and promoting sustainable agricultural development.

Compatibility of <i>Trichoderma asperelloides</i> with Fungicides Controlling Downy Mildew and Powdery Mildew in Grapes

The grape (Vitis vinifera) is an important horticultural crop which belongs to the family Vitaceae. Downy mildew (casual organism: Plasmopara viticola) and powdery mildew (casual organism: Uncinula necator) are two major diseases of grapevine which limit the production of grapes significantly. Both fungicides and bio control agents are used to manage diseases, but both have their own limitations. Integration of bio control agents along with fungicides in disease management helps in reduction of fungicide usage. To understand the effect of these fungicides with commonly used bio-control agents, a compatibility study was carried out under in-vitro condition at ICAR-NRC for Grapes, Pune. Registered fungicides against downy mildew and powdery mildew viz., Mancozeb 75% WP, Dimethomorph 50% WP, Fosetyl Al 80% WP, Amisulbrom 17.7% SC w/w (20% SC w/v), Copper oxychloride 50% WP, Kresoxim methyl 44.3% SC, Tetraconazole 3.8% EW, Metrafenone 50% SC, Cyflufenamid 5% EW and Azoxystrobin 11% + Tebuconazole 18.3% w/w were evaluated for compatibility with a potent bio-control agent viz. Trichoderma asperelloides. Trichoderma asperelloides was found to be fully compatible with Fosetyl Al 80% WP, Amisulbrom 17.7% SC w/w (20% SC w/v) and Cyflufenamid 5% EW and to some extent with Mancozeb 75% WP, Dimethomorph 50% WP at their recommended doses. Such compatibility studies help in understanding the gap between the application of synthetic chemicals and bio control agents.

Assessment of bioagents against cotton diseases under South Gujarat of India

Cotton (Gossypium spp.) is one of the most important economic products of the group of fibres due to volume and value of production. Its cultivation is also of great social importance, due to the number of jobs generated directly or indirectly. The fibre, the main product of cotton has many industrial applications. The manufacturing of yarn for weaving of various kinds of fabrics, cotton batting for hospital use, felt clothing, blankets and upholstery, photographic films and plates for radiography among others. Here in this experiment, different bioagents were evaluated against the cotton foliar disease. This experiment engage the total nine treatments including control from which, treatment T5 (14.50 PDI) (Seed and soil application Pf CICR i.e., seed application: 108cfu/g @10g per kg of seed soil application: 2.5 kg/ha at 30 and 60 DAS) followed by T8 (18.33 PDI) significantly recorded minimum bacterial leaf blight infection in comparison to the treatment T9 i.e. control (42.33 PDI) in RCH 2 BG II hybrid. For Alternaria leaf spot disease, treatment T8 (8.17 PDI) (Seed treatment with Pseudomonas fluorescens CICR (2 x 108cfu/g) @ 10 g/kg seed + soil application of Trichoderma viride TNAU1 (2 x 106 cfu/g) @ 2.5 kg/ha in 250 kg of vermicompost and sprays of Kresoxim methyl (0.0443%) followed by Captan 70% + Hexaconazole 5% WP @ 1.5 g/l) were recorded significantly minimum Alternaria leaf spot disease in RCH 2 BG II hybrid as compared to the T9 i.e. control (19.33 PDI) followed by T7 (9.83 PDI) and T3 (10.50 PDI) treatment. The highest seed cotton yield was recorded in the treatment T5 (2606.00 kg/ha) followed by treatment T8 (2335.33 kg/ha) and treatment T7 (2275.67 kg/ha), respectively.

Carcinogenic and non-carcinogenic risk assessment induced by pesticide residues in fresh pistachio in Iran based on Monte Carlo simulation.

This research is aimed at the analysis of 87 pesticides in 30 fresh pistachio samples prepared from stores in Iran by QuEChERS-ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The results showed at least one pesticide was in 67% of fresh pistachio samples. Kresoxim methyl residue was detected in 20 samples with average of 0.11mgkg-1; this average is 2.2 times more than maximum residue limit (MRL). Buprofezin was recognized in five samples with average of 0.17mgkg-1 was observed with 3.4 times more than MRL; hexaconazole and permethrin were recognized in three samples lower than MRL with an average residue of 0.030 and 0.028mgkg-1, respectively. In addition, potential non-carcinogenic and carcinogenic health risk assessments were evaluated using probabilistic methods performed with the Monte Carlo simulation algorithm. The order of pesticide ranking based on hazard quotient (HQ) was hexaconazole > buprofezin > permethrin > kresoxim methyl. Total HQ (HI) was 2.0E-4 and for children, 9.0E-4. Hence, it means fresh pistachio consuming maybe not have significant short-term health risks for consumer. Ranking based on cancer risk (CR) was hexaconazole > kresoxim methyl > metalaxyl > permethrin > buprofezin. However, total CR due to pesticide residues was not higher than 1E-6 value (1.09E-9); therefore, consumers were not at significant risk of carcinogenicity in this product.

4-Disubstituted Pyrazolin-3-Ones—Novel Class of Fungicides against Phytopathogenic Fungi

The search for fungicides of novel classes is the long-standing priority in crop protection due to the continuous development of fungal resistance against currently used types of active compounds. Recently, 4-nitropyrazolin-3-ones were discovered as highly potent fungicides, of which activity was believed to be strongly associated with the presence of a nitro group in the pyrazolone ring. In this paper, a series of 4-substituted pyrazolin-3-ones were synthesized and their fungicidal activity against an important species of phytopathogenic fungi (Venturia inaequalis, Rhizoctonia solani, Fusarium oxysporum, Fusarium moniliforme, Bipolaris sorokiniana, and Sclerotinia sclerotiorum) was tested in vitro. We discovered that 4-mono and 4,4-dihalogenated pyrazolin-3-ones demonstrate fungicidal activity comparable to that of 4-nitropyrazolin-3-ones and other modern fungicides (such as kresoxim methyl). This discovery indicates that NO2 moiety can be replaced by other groups of comparable size and electronic properties without the loss of fungicidal activity and significantly expands the scope of potent new fungicides based on a pyrazolin-3-one fragment.

Assessment of various fungitoxicants against major diseases of rice

Diseases damage to rice can seriously break productivity and with in short time destroys the crop. Screening of various groups of fungitoxicants in solo and in combination against major diseases of rice was carried out during summer and Kharif 2019. The pooled data revealed Fenoxanil 20% SC + Isoprothiolane 40% EC @ 2ml L-1 was effective in reducing the disease severity of leaf blast and neck blast by recording least percent disease index (PDI) of 13.33 and 12.22 with yield of 5099 kg ha-1as against 40.74 and 48.89 and yield 4034 kg ha-1 in control respectively. The combi fungitoxicants Azoxystrobin 25% SC + Hexaconazole 5% 16.25% SC @ 900 ml ha-1 and Kresoxim methyl 40% + Hexaconazole 8% WG @ 500 g ha-1 were effective against leaf blast, neck blast, sheath blight and sheath rot with PDI 9.25,10.40 13.33 and 17.77 respectively . The tank mix of Hexaconaxole 75% WG and Isoprothiolane 40% EC @ 66.7 g + 750 ml ha-1 was effective against leaf blast, neck blast, sheath blight and sheath rot with least PDI of 2.59, 6.33, 4.81 and 6.85 respectively. Kresoxim methyl 40% + Hexaconazole 8% in combination with Isoprothiolane 40% EC @ 500 g + 750 ml ha-1 recorded the reduced PDI of 4.81, 4.29, 11.85 and 11.11 for leaf blast, neck blast, sheath blight and sheath rot respectively .The fungitoxicants evaluated did not cause any phytotoxicity.

Degradation of Kresoxim-Methyl in Different Soils: Kinetics, Identification of Transformation Products, and Pathways Using High-Resolution-Mass-Spectrometry-Based Suspect and Non-Target Screening Approaches

This study investigated the degradation of strobilurin fungicide kresoxim-methyl (KM) in three typical agricultural soils from China by aerobic and anaerobic degradation experiments, focusing on degradation kinetics of KM, identification of transformation products (TPs), and prediction of toxicity end points via in silico approaches. KM showed a pronounced biphasic degradation in different soils and could rapidly degrade, with DT50 of <3 days. Four TPs were identified by high-resolution mass spectrometry (HRMS), and three of them have never been reported before. Possible degradation pathways of KM in soil were proposed, including hydrolysis, oxidation, and reduction, and the main mechanism involved in the biodegradation of KM was the hydrolysis of methyl ester regardless of aerobic or anaerobic conditions. The results of toxicity evaluation indicated that some TPs are more toxic than KM and may have a developmental toxicity and mutagenicity, and further risk assessment should be carried out.

Histology and metabonomics reveal the toxic effects of kresoxim-methyl on adult zebrafish

Studies have shown that kresoxim-methyl (KM) and other strobilurin fungicides have toxic effects on aquatic organisms. However, the potential deleterious effects of kresoxim-methyl (KM) on adult zebrafish regarding the ecological risk of environmental concentration remain unclear. Here, the histology and untargeted metabonomics was used to investigate the adverse effect on female zebrafish after exposure to KM at environmental concentration, aquatic life benchmark and one-half LC50 of adult zebrafish. Results demonstrated KM affected zebrafish liver, ovary and intestine development, blurred the boundary between hepatocytes or caused hepatic vacuoles, increased the percentage of perinucleolar oocyte and cortical alveolus oocyte, decreased intestinal goblet cells and disturbed villus and wall integrity after 21 d exposure. Metabonomics showed different concentrations of KM simultaneously influenced the metabolites annotated to vitamin digestion and absorption, serotonergic synapse, retinol metabolism, ovarian steroidogenesis and arachidonic acid (AA) metabolism in zebrafish liver. Results showed the decreased triglyceride and cholesterol levels, as well as the metabolic alterations in amino acid, lipid, vitamin and retinol metabolism caused by KM, might disturb the energy supply for normal liver development and oocyte maturation. In addition, KM altered the transcription of Tdo2a, Tdo2b, Ido1, Cxcl8b, Cyp7a, Cyp11a, Cyp11b, Cyp17a, Cyp19a, Hsd3β, Hsd17β, Pla2, Ptgs2a and Ptgs2b, the level of TG, TC, MDA, IFN, IL6 and Ca2+, and the activity of CAT, SOD Ca2+-ATPase in zebrafish liver. Moreover, cytoscape analysis suggested the disturbed AA metabolism caused by KM, might interconnect multiple metabolic pathways to share implicated function in the regulation of oocyte maturation and immune response. Current study brought us closer to an incremental understanding of the toxic mechanism of KM on adult zebrafish, indicated there was crosstalk among different regulatory pathways to regulate the metabolic disorders and biologically hazardous effects induced by KM.

Toxicological differences of trifloxystrobin and kresoxim-methyl on zebrafish in various levels of exposure routes, organs, cells and biochemical indicators

Trifloxystrobin (TRI) and kresoxim-methyl (KRE), as quinone outside inhibitor fungicides (QoIs), have broad applications due to their effective activity against fungi. Excessive usages of agrochemicals trigger environmental risks, such as aquatic organisms (fish). Research performed in recent years has focused on the ecotoxicology of TRI and KRE in fish containing histologic morphology, enzyme activity, protein and gene expression under chronic toxicity conditions, whereas less is known about the underlying mechanisms of toxicity and differences between TRI and KRE in fish under acute toxicity conditions. In the present study, in comparison to different exposure routes [whole-body exposure (WBE), head exposure (HE), trunk exposure (TE), and Oral administration (OA)], the external substances TRI and KRE entered the fish body mainly via gill organs and led to fish toxicity. Furthermore, gill organs and gill cells were vulnerable to TRI and KRE exposure, which indicated that the gill is a vital impaired organ. The 96 h-LC50 (sublethal concentration) value of KRE was 289.8 μg L−1 (R2 = 0.9855) with an approximate 10-fold difference in TRI toxicity. The cytotoxicity exposed to TRI was higher than that in KRE at the same concentration. The potential mechanisms of toxic differences could be various toxic effects in terms of MCIII (mitochondrial complex III) activity, ATP (Adenosine triphosphate) content, MA (mitochondrial activity), ROS (reactive oxygen species) levels, and cellular respiration. Furthermore, the disorder in MCIII activity was probably the main potential mechanisms of toxic differences. To some extent, this research provides not only new insight into the underlying toxic mechanism of TRI and KRE in fish but also a basis for the guidance of agrochemicals considering aquatic risks.

Effect of fungicides and biological products in controlling rust and gray mold in grapevines

Grape rust and gray mold are diseases in grapevines with high destructive potential. In this study, the effectiveness of different fungicides and biological products in controlling these diseases was evaluated using the cultivar “Niágara Rosada” in the municipality of Louveira-SP, from February to April 2017. A randomized block design was used, with 10 treatments and four replicates and five plants per plot. Each treatment was applied nine times at weekly intervals, with application volumes in the range of 400–1000 L/ha. The evaluation criterion for rust was the severity, based on the percentage of leaf area affected by the disease (0 to 100%), whereas gray mold was evaluated using the incidence of diseased bunches (0 to 100%). All treatments were effective in controlling both diseases and significantly reduced the disease incidence in the experimental plot compared with that in the control plots. The best rust control was obtained by treating the plants with boscalide+pyraclostrobin (1 L c.p./ha), which was superior to fluxapyroxade+pyraclostrobin (0.5 L) + Bacillus amyloliquefaciens (0.5 kg), B. amyloliquefaciens (0.5 kg), Melaleuca alternifolia essential oil (1.5 L), and dimoxystrobin+boscalide (1 L). The plants treated with fluxapyroxad+pyraclostrobin (0.5 L) + B. amyloliquefaciens (0.5 kg) had a lower incidence of gray mold than did those treated with dimoxystrobin+boscalide (1 L), boscalide+kresoxim methyl (0.5 L), and piremethanil (1.5 L). These results suggest that the use of M. alternifolia essential oil and B. amyloliquefaciens may represent an important tool for the management of rust and gray mold in grapevines.

A multiplex lateral flow immunochromatography assay for the quantitative detection of pyraclostrobin, myclobutanil, and kresoxim-methyl residues in wheat

We produced three monoclonal antibodies with high specificity and sensitivity, and developed a lateral flow immunochromatography assay (LFIA) for the qualitative and quantitative detection of pyraclostrobin (PYR), myclobutanil (MYC), and kresoxim-methyl (KRE) in wheat. In the qualitative analysis, the cut-off values of LFIA were 400, 200, and 800 ng/g for PYR, MYC, and KRE in wheat, respectively. Based on the results obtained from the membrane strip reader, we generated calibration curves for the quantitative analysis. PYR, MYC, and KRE monoclonal antibodies (mAbs) had half maximal inhibitory concentrations (IC50) of 25.4, 17.7, and 94.6 ng/g, respectively, and limit of detection (LOD) of 2.5, 2.0, and 8.8 ng/g, respectively. The linear detection scopes were 5.6–116.5, 4.2–74.4, 23.4–383.3 ng/g for PYR, MYC, and KRE, respectively. The intra-assay recoveries ranged from 89.2% to 101.7%, and the coefficients of variation ranged from 4.6% to 6.5%. The inter-assay recoveries ranged from 88.7% to 102.7%, with the coefficients of variation ranged from 7.2% to 9.1%. Thus, our developed LFIA is suitable for the qualitative and quantitative detection of PYR, MYC, and KRE residues in wheat.

Design, Synthesis, and Evaluation of Fungicidal Activity of Novel Pyrazole‐Containing Strobilurin Derivatives†

Main observation and conclusionIn searching for novel fungicidal leads, a series of pyrazole‐containing strobilurins were rationally designed, synthesized and characterized. Bioassay indicated that compound I‐7 displayed excellent fungicidal activity against a broad spectrum of plant pathogens such as Gibberella zeae, Rhizoctonia cerealis, Sclerotinia sclerotiorum, Phytophthora infestans, Physalospora piricola and Pellicularia sasakii with EC50 of 0.16, 0.02, 0.72, 0.07, 0.77 and 0.65 μg/mL, respectively, which were 3—10 times more potent than the positive control azoxystrobin against the corresponding pathogens. Moreover, like azoxystrobin and kresoxim methyl, I‐7, displayed excellent protective activity against P. sorghi. Molecular docking validated that I‐7 and azoxystrobin would share a similar binding mode with cytochrome bc1 complex. This study demonstrates that I‐7 is a promising fungicidal candidate for further development.

Kresoxim methyl SC-a Quinone Outside Inhibitor against Major Fungal Foliar Diseases of Apple

Scab and Alternaria leaf blotch are the major destructive diseases of apple causing enormous loss to apple orchards of Kashmir and other states of India. The present study reports the bio-efficacy of kresoxim methyl 44.3 gL−1SC-a quinone outside inhibitor (QOI), against these diseases. The fungicide was evaluated at 0.03, 0.04 and 0.05 per cent concentrations at two different locations for two consecutive years (2014 and 2015) under epiphytotic conditions of Kashmir valley. The performance was compared with recommended standard fungicides viz., tebuconazole 25.9 EC, hexaconazole 5 EC and difenaconazole 25 EC at 0.05, 0.05 and 0.03 per cent concentrations, respectively, besides the water sprayed trees as check. The fungicide, during both the seasons and at both the locations, provided the best protection against scab and Alternaria leaf blotch. The trees treated with kresoxim methyl at 0.05 per cent concentration provided 97.25 and 97.70 per cent control of leaf scab incidence and intensity as against 95.72 and 97.43, 88.70 and 91.47 and 77.70 and 78.89 per cent observed in standards difenaconazole 25 EC, tebuconazole and hexaconazole respectively. The fungicide was significantly superior to standards tebuconazole 25.9 EC and hexaconazole 5 EC and was statistically at par with difenaconazole. Similarly, the fungicide gave an average fruit scab control of 98.00 and 98.48 per cent in incidence and intensity as against 97.25 and 97.60, 92.18 and 93.63, and 83.54 and 87.20 per cent recorded in standard difenaconazole, tebuconazole and hexaconazole, respectively. At 0.05 per cent concentration it performed efficiently in controlling Alternaria leaf blotch of apple with 94.65 and 95.20 per cent in incidence and intensity as against 94.65, 89.80 and 84.70 per cent in incidence with an intensity of 96.10, 90.56 and 85.03 per cent achieved with difenaconazole, tebuconazole and hexaconazole sprayed trees, respectively. Thus, based on two year data at two locations and comparison with the standards, it was concluded that use of kresoxim methyl at 0.04 to 0.05 per cent concentrations is effective in controlling leaf/fruit scab and Alternaria leaf blotch diseases of apple. Phytotoxicity study with the test fungicide carried out at 0.05 and 0.1 per cent concentrations on commercial apple cultivars (Red delicious and Red chief) during both the seasons and locations, revealed no sign of toxicity on fruits, leaves and other parts of the trees.

Variability in Rhizoctonia solani causing sheath blight of rice and its chemical management

Rhizoctonia solani is infamous fungus for its highly destructive pathogenic effect that can result in extensive damage of rice crop. To know the variability among the Indian isolates of R. solani inciting sheath blight in rice, four isolates were isolated from diseased samples of Uttar Pradesh, Uttrakhand, Gujarat and Karnataka states of India. Variability in isolates was observed with respect to the cultural, morphological and pathogenic level. Evaluation of toxicity of various fungicides against R. solani under in vitro condition showed the maximum sensitivity of R. solani by carbendazim even at 1 ppm concentration followed by Tebuconazole + trifoxystrobin and Hexaconazole. R. solani showed good tolerance to Kresoxim methyl even at 100 mg kg-1 concentration. All tested fungicides namely Propiconazole, Hexaconazole, Kresoxim-methyl, Tebuconazole 50% + Trifloxystrobin 25%, Tricyclazole and Carbendazim caused complete inhibition of colony growth of R.solani at 1000 ppm. Foliar spray of Carbendazim @ 0.1% was found highly effective for the management of sheath blight in field condition with highest per cent reduction in disease (86.29%) followed by Tebuconazole + Trifloxystrobin (83.30%), Hexaconazole (74.20%) and Propiconazole (45.28%). Plots treated with Tricyclazole and Kresoxim Methyl had only 29.15 and 12.24 per cent reduction over control, respectively.