Evaluation of Pyraclostrobin as an Ingredient for Soybean Seed Treatment by Analyzing its Accumulation–Dissipation Kinetics, Plant-Growth Activation, and Protection Against Phytophthora sojae

Abstract

Seed treatment with fungicides has been regarded as a principal, effective, and economic technique for soybean [ Glycine max (L.) Merr.] against pathogenic microorganisms during seed germination and seedling growth. Investigation of the characteristics of seed-treatment reagents is an indispensable basis for their application. The aim of the present work is to evaluate the use of pyraclostrobin as an ingredient for soybean seed treatment by investigating its accumulation−dissipation kinetics in plants, plant-growth activation, and protection against Phytophthora sojae. The results showed that the pyraclostrobin stimulated the visible growth (root and shoot length) of soybean plants, increased the chlorophyll level and root activity, and lowered the malonaldehyde (MDA) level. The peak level and bioavailability of pyraclostrobin in soybean roots were 19.9-and 33.2-fold those in leaves, respectively, indicating that pyraclostrobin was mainly accumulated in roots. Pyraclostrobin had a continuous positive effect on the flavonoid levels and the phenylalanine ammonialyase (PAL) activity in roots and leaves, which could enhance the plant defense system. Pyraclostrobin showed in vitro toxicity to P. sojae with a half-inhibition concentration (EC 50 ) of 1.59 and 1.24 μg/mL for pyraclostrobin and pyraclostrobin plus salicylhydroxamic acid (SHAM, an inhibitor of the alternative pathway of respiration), respectively. Seed treatment with pyraclostrobin significantly reduced the severity of Phytophthora root rot, with a control efficacy of 60.7%. To the best of our knowledge, this is the first report on the characteristics of pyraclostrobin used in soybean seed treatment and its efficacy against Phytophthora root rot.

Agronomic and efficacy evaluations of oxathiapiprolin as a soybean seed treatment

“…In a different study, soybean treated with pyraclostrobin was calculated to have a control efficacy of 60.7% (Li et al., 2020). Seedlings treated with pyraclostrobin appeared to have some protection against P. sojae , but disease symptoms were evident and root/leaf malformation were noted (Li et al., 2020). The disease symptoms described in the literature with other fungicide seed treatments were not detected in any of the seed treatments with oxathiapiprolin tested in this manuscript.…”

“…Seed treatments with azoxystrobin, trifloxystrobin, and pyraclostrobin did not show significant control of reducing P. sojae (Ellis et al., 2008). In a different study, soybean treated with pyraclostrobin was calculated to have a control efficacy of 60.7% (Li et al., 2020). Seedlings treated with pyraclostrobin appeared to have some protection against P. sojae , but disease symptoms were evident and root/leaf malformation were noted (Li et al., 2020).…”

“…The data collected for oxathiapiprolin are similar compared to pyraclostrobin as a soybean seed treatment, where plant growth and an increase in chlorophyll were observed in laboratory conditions (Li et al, 2020). However, there are currently no literature articles that report methods of utilizing UAV image-to-data analysis to quantify greenness or plant health for soybean seed treatments in wide-area agronomic testing across multiple years.…”

Comparative Performance of Fungicides, Biofungicides, Host-plant Defense Inducers, and Fertilizer in Management of Phytophthora Root Rot on Boxwood

“…A study on leather root rot of Fragaria ananassa Duchesna caused by Phytophthora cactorum (Libert and Cohn) J. Schr€ ot showed that pyraclostrobin provided excelling control (Rebollar-Alviter and Ellis, 2005). Another experiment on managing P. sojae on soybean using pyraclostrobin as seed treatment showed efficacy for increased chlorophyll level, shoot and root length, root activity, and continuous positive effect on enhancing the plant defense (Li et al, 2020). In contrast, some studies showed decreased sensitivity of P. capsici causing Phytophthora blight in pepper against quinone-outside inhibitor (QoI) fungicides including pyraclostrobin (Ma et al, 2018), suggesting the necessity of using fungicides in rotation to save crops from increased resistance.…”

The effect of polyethersulfone and nylon 6 micromembrane filters on the pyraclostrobin detection：Adsorption performance and mechanism

“…Once applied, however, pesticides would enter the surrounding environment through pesticide drift, surface water ow, and soil deposition (Druart et al, 2011). Pyraclostrobin, a strobilurin fungicide, has been applied to a wide range of crops due to its high activity against fungi (Li et al, 2018c)and its unique function to improve crop growth characteristics (Li et al, 2020). Consequently, it has been frequently detected in water bodies and sediments adjacent to highly agricultural areas.…”