Dictyophora rubrovolvata is an important edible mushroom that is widely cultivated in China. In 2019, a serious rot disease on D. rubrovolvata was observed in a mushroom production facility located in Ce Heng County, Southwest of Guizhou Province, China. The causal agent was identified as Trichoderma koningiopsis by amplification and sequencing of the internal transcribed spacer (ITS) region, the translation elongation factor 1-alpha (EF-1α) gene, and the RNA polymerase II subunit (RPB2) gene followed by phylogenetic analysis. Koch's postulates were confirmed by a pathogenicity test that was conducted with healthy D. rubrovolvata, including re-isolation and identification. To our knowledge, this is worldwide the first report of T. koningiopsis as a pathogen on D. rubrovolvata causing green mold disease.

Passion fruit (Passiflora edulis Sims) is a widely cultivated dicotyledonous perennial plant with woody vines (Asande et al. 2020). In November 2020, leaf blight was observed on leaves of P. edulis (cultivar: ‘Panama Red’) newly planted in Wangyou, Huishui county, Guizhou province, China (25°82'57" N, 106°50’49" E). The leaf blight occurred on both young and old leaves, starting from the margins, and then extended to the entire leaves. The color of the affected tissue was brown with a yellow hallo in the early period, and then gradually turned to grey. The disease incidence was 60%-70% on a 0.08-ha field. Following isolation of the potential pathogen from 12 diseased leaves, nine isolates were obtained. The colonies were white with a regular round shape at the early stage and became black with fluffy hyphae after eight days on potato dextrose agar (PDA) medium, incubated at 25°C in the dark for 10 days. The single cell conidia were solitary, spherical or slightly ellipsoidal, black, shiny, smooth, aseptate, spherical, and 8.1–13.5 μm (n=50) in diameter. Conidiophores (5.2-9.9 × 4.4-7.2 μm) were mostly reduced to conidiogenous cells and aggregated in clusters on hyphae. Conidiogenous cells were hyaline to pale brown or black, globose to ampulliform or clavate. Morphological characteristics of the isolates matched the description of the genus Nigrospora Mei Wang & L. Cai (Wang et al. 2017). For molecular identification, DNA was extracted, and PCRs were performed with primers ITS1/ITS4 for the ITS region (White et al. 1990), primers Bt2a/Bt2b for the β-tubulin gene (TUB) (Glass and Donaldson 1995), and primers EF1-728F/EF1-986R for the translation elongation factor 1-alpha gene (EF1-α) (Carbone and Kohn 1999). Representative sequences of the ITS region, EF1-α, and TUB sequences (from isolate WYR007) were deposited in GenBank (accession numbers: MW561355; MZ053463; MZ032030) and are included in the supplementary materials. BLAST analysis against sequences from previously published studies showed 99.58% (ITS region), 99.54% (EF1-α), and 99.45% (TUB) identity to Nigrospora sphaerica sequences (accession numbers: MN215808.1; MN864137.1; KY019606.1). In addition, homology was confirmed with a phylogenetic tree using concatenated sequences from ITS, EF1-α and TUB constructed with MEGA 7 for which the maximum likelihood method was used with 1,000 bootstrapping iterations. To complete Koch’s postulates, conidia suspensions of isolate WYR007 (prepared from 1-month-old colonies in 0.05% Tween 20 buffer and adjusted to a concentration of 1 × 103 conidia/mL) were sprayed on 15 leaves (200 μL per leaf) of 5 one-year-old healthy P. edulis plants (cultivar: ‘Panama Red’). The same number of leaves from control group plants was only treated with 0.05% Tween buffer. All plants were incubated at 26°C ± 2°C under a 16 h/8 h photoperiod and 70%–75% relative humidity (RH) after inoculation. After 14 days, symptomatic blight appeared on all inoculated leaves. In contrast, no symptoms appeared on leaves in the control group. The disease assays were repeated three times. Pure cultures were re-isolated from diseased leaves and confirmed to be N. sphaerica based on the morphological and molecular methods mentioned above (ITS region, the TUB, and the EF1-α sequences). To our knowledge, this study is the first report of N. sphaerica as a pathogen on P. edulis causing leaf blight. The identification of the pathogen could provide relevant background for its future management.s Sims) is a widely cultivated dicotyledonous perennial plant with woody vines (Asande et al. 2020). In November 2020, leaf blight was observed on leaves of P. edulis (cultivar: ‘Panama Red’) newly planted in Wangyou, Huishui county, Guizhou province, China (25°82'57" N, 106°50’49" E). The leaf blight occurred on both young and old leaves, starting from the margins, and then extended to the entire leaves. The color of the affected tissue was brown with a yellow hallo in the early period, and then gradually turned to grey. The disease incidence was 60%-70% on a 0.08-ha field. Following isolation of the potential pathogen from 12 diseased leaves, nine isolates were obtained. The colonies were white with a regular round shape at the early stage and became black with fluffy hyphae after eight days on potato dextrose agar (PDA) medium, incubated at 25°C in the dark for 10 days. The single cell conidia were solitary, spherical or slightly ellipsoidal, black, shiny, smooth, aseptate, spherical, and 8.1–13.5 μm (n=50) in diameter. Conidiophores (5.2-9.9 × 4.4-7.2 μm) were mostly reduced to conidiogenous cells and aggregated in clusters on hyphae. Conidiogenous cells were hyaline to pale brown or black, globose to ampulliform or clavate. Morphological characteristics of the isolates matched the description of the genus Nigrospora Mei Wang & L. Cai (Wang et al. 2017). For molecular identification, DNA was extracted, and PCRs were performed with primers ITS1/ITS4 for the ITS region (White et al. 1990), primers Bt2a/Bt2b for the β-tubulin gene (TUB) (Glass and Donaldson 1995), and primers EF1-728F/EF1-986R for the translation elongation factor 1-alpha gene (EF1-α) (Carbone and Kohn 1999). Representative sequences of the ITS region, EF1-α, and TUB sequences (from isolate WYR007) were deposited in GenBank (accession numbers: MW561355; MZ053463; MZ032030) and are included in the supplementary materials. BLAST analysis against sequences from previously published studies showed 99.58% (ITS region), 99.54% (EF1-α), and 99.45% (TUB) identity to Nigrospora sphaerica sequences (accession numbers: MN215808.1; MN864137.1; KY019606.1). In addition, homology was confirmed with a phylogenetic tree using concatenated sequences from ITS, EF1-α and TUB constructed with MEGA 7 for which the maximum likelihood method was used with 1,000 bootstrapping iterations. To complete Koch’s postulates, conidia suspensions of isolate WYR007 (prepared from 1-month-old colonies in 0.05% Tween 20 buffer and adjusted to a concentration of 1 × 103 conidia/mL) were sprayed on 15 leaves (200 μL per leaf) of 5 one-year-old healthy P. edulis plants (cultivar: ‘Panama Red’). The same number of leaves from control group plants was only treated with 0.05% Tween buffer. All plants were incubated at 26°C ± 2°C under a 16 h/8 h photoperiod and 70%–75% relative humidity (RH) after inoculation. After 14 days, symptomatic blight appeared on all inoculated leaves. In contrast, no symptoms appeared on leaves in the control group. The disease assays were repeated three times. Pure cultures were re-isolated from diseased leaves and confirmed to be N. sphaerica based on the morphological and molecular methods mentioned above (ITS region, the TUB, and the EF1-α sequences). To our knowledge, this study is the first report of N. sphaerica as a pathogen on P. edulis causing leaf blight. The identification of the pathogen could provide relevant background for its future management.

Biological and biochemical methods, based on glufosinate inhibitory effects on plant growth and nitrogen metabolism, were examined for their applications to detect this herbicide. Dose-response analysis of radicle growth inhibition showed that, among six vegetables tested, Chinese mustard and edible amaranth were the most sensitive to glufosinate. Field mustard and cruciferous Ching-Geeng were found to be more sensitive to this herbicide than the other four vegetables when three-leaf-seedlings were tested in another bioassay. In three-leaf seedlings of Ching-Geeng, accumulation of ammonium, a biochemical marker for glufosinate toxicity because of its inhibition of glutamine synthetase, showed a linear regression to the log-transformed concentrations of glufosinate ranging from 7.5 X 10(-5) to 1.5 X 10(-3) M. For the detection of glufosinate lower than 7.5 X 10(-6) M, a linear regression was observed between ammonium accumulation and the applied concentration, instead of the log-trans- formed value, of glufosinate. A similar relationship was observed between the accumulation in Ching-Geeng seedlings of glyoxylate, another biochemical marker, and glufosinate but with a narrower range than that for ammonium accumulation. The applicability of ammonium accumulation in three-leaf seedlings of Ching-Geeng to detect glufosinate residue in water and soil was confirmed by high-performance liquid chromatography (HPLC)

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