Applications Of Fluazinam Research Articles

Optimizing fungicide timing for the management of white mold in processing snap bean in New York

White mold (Sclerotinia sclerotiorum) is the most important fungal disease affecting processing snap bean production in New York (USA). The most important tactic for in-season disease management is fungicide application with the aim of protecting flowers from infection by S. sclerotiorum ascospores. The most popular fungicide is thiophanate-methyl but for rotational purposes, boscalid and fluazinam are common although more expensive alternatives. Despite the application of fungicides, white mold often occurs. In the absence of knowledge on optimal fungicide timing, up to two applications may be made with the first occurring at 10% of plants having at least one open flower, and the second approximately seven days thereafter coinciding with full (100%) flowering and pin-pod. Six small plot, replicated field trials were conducted over three years (2015–2017) to identify optimal timings for the most commonly used fungicides (thiophanate-methyl, boscalid, and fluazinam) to reduce the incidence of white mold in processing snap bean cvs. Huntington and Denver. Fungicides were applied at either early (10%) and/or late (100%) flowering and the effect on white mold incidence in pods and plants, green leaf area measured using canopy reflectance at 830 nm, and pod yield was evaluated. Application of thiophanate-methyl at early flowering was optimal for reducing the incidence of white mold and a second application at late flowering was not beneficial. In contrast, if thiophanate-methyl application was delayed until late flowering, white mold incidence was high and in some cases not significantly different from nontreated plots. Timing of fluazinam or boscalid was more flexible and not significantly different between a single application at early or late flowering. Two applications of fluazinam or boscalid did not significantly reduce white mold compared to a single application. Delayed application of thiophanate-methyl to later in flowering may be a contributing factor in the suboptimal management of white mold in processing snap bean. Optimal timing of fluazinam or boscalid appears less critical and offers growers flexibility when conditions are not optimal for application at early flowering. In addition, these products allow for rotation to different modes of action, but with trade-offs in cost.

Impact of fluazinam on morphological and physiological characteristics of Sclerotinia sclerotiorum

Sclerotinia sclerotiorum is a necrotrophic and filamentous fungus with a broad host range. Fluazinam is a pyridinamine fungicide with a broad spectrum of antifungal activity and had a strong inhibition effect on mycelial growth of S. sclerotiorum populations. But the impact of fluazinam on morphological and physiological characteristics of S. sclerotiorum is little known. In this study, the EC50 values of fluazinam to three strains of S. sclerotiorum (CZ17S, YZ55S and SA42S) were 0.0084, 0.007, 0.0065 μg/ml respectively. After fluazinam treatment, hyphae of S. sclerotiorum became thinner, hyphal offshoot of top increased, the distance between one septum and another became shorter, cell membrane permeability increased markedly, exopolysaccharide (EPS) content and oxalic acid content decreased significantly, peroxidase (POD) activity increased significantly and mycelial respiration was inhibited. While the number and dry weight of sclerotia, glycerol content in the mycelia did not significantly change. In protective activity assay on detached rapeseed leaves, application of fluazinam at 40 μg/ml and 80 μg/ml, the control efficacy reached to 41.4% and 100%, respectively. In curative activity assay, application of fluazinam at 100 μg/ml, the control efficacy reached to 61.09%. In the same concentration, protective activity of fluazinam against S. sclerotiorum was higher than curative activity. These results will contribute to us on evaluating the potential of the fungicide fluazinam for management of Sclerotinia stem rot and understanding the mode of action of fluazinam against S. sclerotiorum.

Activity of the dinitroaniline fungicide fluazinam against Bipolaris maydis

Fluazinam is a dinitroaniline fungicide with broad-spectrum activities. However, the activity of fluazinam against Bipolaris maydis which is the causal agent of southern corn leaf blight is unknown yet. In this study, baseline sensitivity of B. maydis to fluazinam was determined using 92 isolates collected during 2015 and 2016 from different geographical regions in Jiangsu Province of China, and the EC50 values ranged from 0.0396 to 0.9808 μg/ml with average value of 0.3853 ± 0.2297 μg/ml, and 0.079 to 0.7832 μg/ml with average value of 0.3065 ± 0.1384 μg/ml for mycelial growth and conidium germination respectively. Fluazinam did not affect the distribution of cell nucleus and the formation of septum of B. maydis. However, fluazinam could make mycelium of B. maydis contorted and the mycelial branches increased and inhibit the development of conidia. The result of transmission electron microscope showed that fluazinam damaged cell wall and cell membrane of mycelium, and make organelles in mycelial cell dissolved and vacuolated, and the cell almost broke up, which caused the intracellular plasma leakage increase. The protective activity test of fluazinam suggested that fluazinam had great control efficiency against B. maydis on detached corn leaves. Application of fluazinam at 10 μg/ml and 20 μg/ml, the control efficacy reached to 87.70% and 98.25% respectively. However, fluazinam had no curative activity against B. maydis on detached corn leaves. These results will contribute to us on evaluating the potential of the dinitroaniline fungicide fluazinam for management of diseases caused by B. maydis and understanding the mode of action of fluazinam against B. maydis.

English

The aim of this study was to evaluate different alternative products, foliar sprayed either alone or in combination with fungicide fluazinam, to control white mold in soybean at three locations: Arapoti, Maua-da-Serra, and Pinhao, in Parana state, southern Brazil. The following chemical products were used: sodium dichloroisocyanurate, benzalkonium chloride, pyroligneous extract, sodium hypochlorite, cobalt + molybdenum, sucrose, sodium bicarbonate and acibenzolar-S-methyl. Incidence, severity, yield, and number of sclerotia produced were analyzed. The majority of the variables did not follow the normal distribution of the data according to the Kolmogorov-Smirnov test; therefore, the use of non-parametric analysis was necessary. The analysis of all the treatments individually revealed no significant effects so it was decided to separate the analysis into the following groups of treatments: ‘control’, treatments using alternative products (‘alternatives’), treatment only with fungicide (‘fungicide’) and treatments with alternative products and fungicide (‘alternatives + fungicide’). In Arapoti, no significant differences for any variables were observed. In Maua-da-Serra, the ‘fungicide’ and ‘alternatives + fungicide’ had the lowest incidence and number of sclerotia, with higher yield when compared to ‘control’ and ‘alternatives’. No differences were observed for severity. In Pinhao, the ‘fungicide’ and ‘alternatives + fungicide’ were superior for incidence, number of sclerotia produced, and yield when compared to the ‘control’ and ‘alternatives’. The ‘alternatives + fungicide’ showed significantly lower severity when compared to the control, ‘alternatives’ and ‘fungicide’ in Pinhao experiment. In conclusion, the alternative products applied in combination with fluazinam resulted in lower severity of white mold in soybean in the experiment conducted in Pinhao, and the application of fluazinam alone or in combination with alternative products, was efficient to control white mold in soybean in locations with high disease incidence.

根部増強処理によるナシ白紋羽病発病樹の樹勢回復

Recovery of Japanese pear trees from a decline associated with white root rot caused by Rosellinia necatrix was examined after root reinforcement treatment with healthy stocks. Fluazinam alone, which is highly effective against white root rot, could not reverse the decline. However, the declined trees were recovered successfully from the syndrome after application of Fluazinam in combination with the root reinforcement treatment with some healthy stocks.

Activity of Boscalid, Fenhexamid, Fluazinam, Fludioxonil, and Vinclozolin on Growth of Sclerotinia minor and S. sclerotiorum and Development of Lettuce Drop.

Sclerotinia drop is a major disease of lettuce caused by two soilborne fungi, Sclerotinia minor and S. sclerotiorum. Fungicides such as dicloran (Botran), iprodione (Rovral), and vinclozolin (Ronilan) are currently available in the United States to manage this disease. Studies were conducted to investigate the relative effect of some new fungicides, including boscalid, fenhexamid, fluazinam, and fludioxonil, in comparison with vinclozolin, on growth of S. minor and S. sclerotiorum in agar plate tests as well as control of lettuce drop in the field. At a rate of 0.001 μg/ml, all tested compounds only suppressed mycelial growth of either pathogen from 0 to 20%. At 0.01 μg/ml, mycelial growth of S. minor was reduced 82 to 84% by fludioxonil and fluazinam and only 1 to 16% by boscalid, fenhexamid, and vinclozolin. At the same rate, mycelial growth of S. sclerotiorum was reduced 78% by fluazinam and from 0 to 12% by boscalid, fludioxonil, fenhexamid, and vinclozolin. At 0.1 μg/ml, all tested chemistries except vinclozolin inhibited mycelial growth of S. minor from 70 to 98%, whereas growth of S. sclerotiorum was suppressed 95 to 99% by fludioxonil and fluazinam, significantly less (40 to 47%) by boscalid and fenhexamid, and not at all by vinclozolin. At a rate of 1.0 μg/ml, all tested fungicides reduced mycelial growth of S. minor and S. sclerotiorum from 87 to 100% and 77 to 100%, respectively. Mycelial growth emerging from sclerotia of S. minor was reduced from 98 to 100% by all fungicides tested at a rate of 1.0 μg/ml, whereas growth from sclerotia of S. sclerotiorum was suppressed from 90 to 96% by fenhexamid, fludioxonil, fluazinam, and vinclozolin. In lettuce plots infested with S. minor, boscalid and fluazinam provided the highest level of disease control, significantly greater than that achieved with fenhexamid, fludioxonil, and vinclozolin. In the presence of S. sclerotiorum, the highest degree of disease suppression occurred with application of fluazinam, fludioxonil, and vinclozolin, whereas the least effective compound was fenhexamid. Boscalid and fluazinam were more effective against lettuce drop caused by S. minor than disease caused by S. sclerotiorum.

Integrated Management of Sclerotinia Blight in Peanut: Utilizing Canopy Morphology, Mechanical Pruning, and Fungicide Timing.

Sclerotinia blight of peanut, caused by Sclerotinia minor, generally becomes severe only after vines meet in the row middles and a dense canopy develops. Dense foliage appears to support a microclimate conducive to the colonization of peanut limbs by S. minor. Removal of excess foliage before and during a Sclerotinia blight epidemic on the susceptible genotype NC 7 has been shown to reduce the rate of disease progress. Field tests in 1993 and 1994 examined control of Sclerotinia blight among four peanut genotypes (NC 7, VA 93B, NC Ac 18016, and Tam-span 90) with diverse canopy morphologies. Each cultivar had foliage pruned with a rotary mower once (1993 and 1994) or twice (1994) during the season. Applications of fluazinam (9.2 kg a.i./ha) were imposed on the genotype × pruning treatments. Soil temperatures under the canopy of each genotype and pruning treatment were measured and compared. Disease data were collected weekly by counting the number of feet of plants exhibiting lesions with visible fungus growth. Tamspan 90, a resistant Spanish peanut, had the least Sclerotinia blight incidence. Pruning measurably affected soil temperature for approximately 2 weeks following pruning. Removal of foliage reduced disease and increased disease control affected by fluazi-nam in fields with high disease pressure. In some tests, yields were increased by pruning through a reduction in disease pressure. Yields were lower when peanuts were pruned excessively, especially late in the season. Pruning of excessive vine growth can be an alternative, or complement, to fungicide treatments when done in midseason during favorable weather when moderate to high disease pressure occurs.

Fluazinam: A New Fungicide for Control of Sclerotinia Blight and Other Soilborne Pathogens of Peanut1

Abstract Fluazinam provided effective control of Sclerotinia blight (Sclerotinia minor Jagger) of peanut in six field trials during a 4-yr period. Applications of fluazinam (0.56 kg/ha) at the onset of Sclerotinia blight and 4 wk later provided an average of 69% suppression of disease incidence and increased yields by 1598 kg/ha compared to untreated plots. Performance of fluazinam was significantly better than iprodione, the material currently used for control of Sclerotinia blight. Two applications of iprodione at 1.12 kg/ha provided only 31% suppression of disease incidence and increased yield by 718 kg/ha. Fungicides were also evaluated in 1990 as tank-mixes with chlorothalonil (1.26 kg/ha) that were applied in foliar sprays according to the Virginia peanut leafspot advisory program. Treatments consisted of no fungicide, chlorothalonil alone, and tank-mixes of chlorothalonil plus either dicloran at 2.10 kg/ha, fluazinam at 0.56 kg/ha, or iprodione at 0.84 kg/ha. Sclerotinia blight at harvest in untreated plots and plots treated with chlorothalonil alone averaged 27.8 and 35.8 disease foci per plot, whereas yields averaged 3624 and 2251 kg/ha, respectively. Compared to plots treated with chlorothalonil alone, Sclerotinia blight was suppressed by 92, 25, and 25%, and yield was increased by 4020, 1925, and 1684 kg/ha in plots treated with chlorothalonil plus either fluazinam, iprodione, or dicloran, respectively. Applications of tank-mixes containing fluazinam plus chlorothalonil in 1991 provided additional evidence that this approach was a highly effective means of controlling both Sclerotinia blight and early leafspot, a previously unattainable goal. Fluazinam did not control early leafspot (Cercospora arachidicola S. Hori) in field trials; however, the fungicide was fungitoxic in vitro to Sclerotium rolfsii Sacc. and Rhizoctonia solani Kühn.