Clubroot is a major disease of cruciferous crops worldwide, and accurate assessment of pre-plant disease risk is essential for effective management. Although increasing soil pH is widely regarded as an effective strategy for suppressing clubroot, contradictory findings have been reported, including disease development under high-pH conditions and weak correlations between pH and disease development. Recently, Health Checkup-Based Soilborne Disease Management (HeSoDiM) has adopted dose–response curves (DRC) for evaluating the disease potential (D-potential) of soilborne diseases. In this study, we investigated inter-field variation in D-potential under high resting spore density. By integrating DRC diagnostic data with pH intervention experiments and analyzing the combined dataset using a generalized linear mixed model (GLMM), soil pH was identified as the factor most strongly associated with disease suppression. Exchangeable potassium and cation exchange capacity (CEC) were also identified as candidate factors associated with variation in D-potential. In the primary GLMM analysis, only soil pH was significantly associated with disease suppression. In an additional analysis excluding four soils that exhibited shoot browning without clubroot symptoms, both soil pH and CEC were significantly associated with D-potential classification. Furthermore, a preliminary zeolite experiment conducted under conditions of high pH, high CEC, and high exchangeable potassium suggested that disease development may occur even under elevated pH conditions. These findings indicate that soil pH is the primary factor associated with clubroot suppression, whereas the roles of CEC and exchangeable potassium require further investigation.
Leaf blight was observed on greenhouse-grown Liriope muscari in Hwaseong-si, Korea, in January 2026. A Botrytis isolate from symptomatic leaves produced gray colonies and ellipsoid to ovoid conidia. Internal transcribed spacer data supported placement within Botrytis, and multilocus phylogeny identified the isolate as Botrytis squamosa. Mycelial plug inoculation reproduced symptoms on L. muscari, and the fungus was re-isolated. In a detached-leaf assay, the isolate also produced necrotic lesions on onion (Allium cepa). This study reports leaf blight of L. muscari caused by B. squamosa in Korea and indicates that L. muscari represents a non-Allium host of this pathogen.
Mobile chromosomes have been shown to undergo horizontal transfer in several fungal species. However, their transfer efficiencies have not been systematically compared. The cabbage-infecting pathogen Fusarium oxysporum f. sp. conglutinans strain Cong:1–1 harbors three mobile chromosomes, corresponding to scaffold (SC) 8, SC9, and a combined chromosome consisting of SC10 and SC20 (chrSC10/SC20). Herein, we investigated the differences in horizontal transfer efficiency in vitro between SC9 and chrSC10/SC20. The efficiency of SC9 transfer to two non-pathogenic F. oxysporum strains was lower than that of chrSC10/SC20. Furthermore, chrSC10/SC20 is transferred into a recipient strain within a shorter cocultivation period than SC9. Although pathogenic and non-pathogenic F. oxysporum strains can survive in soil, it remains unclear whether horizontal chromosome transfer occurs during saprophytic growth, as previous observations have been limited to in vitro conditions. We observed horizontal transfer of the mobile chromosomes of Cong:1–1 during saprophytic growth in soil. These findings contribute to our understanding of the dynamics of mobile chromosomes in fungi.
Pileus and stipe rot disease was observed on Morchella importuna under greenhouse conditions in Türkiye. Infected fruiting bodies exhibited white, cottony to velvety mycelial growth on the pileus and stipe, followed by tissue browning, softening, and collapse. The causal agent was identified as Pseudodiploöspora longispora based on morphological characteristics and ITS and TEF1-α sequence analyses. Phylogenetic reconstruction confirmed its placement within the P. longispora clade with strong bootstrap support. Pathogenicity tests reproduced symptoms, and the fungus was re-isolated, fulfilling Koch’s postulates. This study represents the first report of P. longispora causing pileus and stipe rot on M. importuna in Türkiye.
Bacterial seedling rot of rice caused by Burkholderia glumae is a serious disease that impairs seedling development and causes seedling blight. To control this disease without depending on chemical fungicides, new strategies are required because of the emergence of fungicide-resistant strains and the environmental impacts of agriculture. In this study, we evaluated the suppressive effects of converter slag fertilizer, a steel-making by-product composed of inorganic elements, when mixed into a seed-soaking solution. Higher concentrations of powdered converter slag fertilizer in the seed-soaking solution markedly suppressed disease development. Furthermore, disease suppression occurred in a stepwise manner, with symptoms suppressed in order of severity as the fertilizer amount increased. Analysis of water-soluble elements in the seed-soaking solution suggested that multiple elements eluted from the fertilizer may be associated with the disease-suppressive environment generated during seed soaking. Notably, Ca2+ was the most abundant water-soluble element and may contribute to disease suppression. These findings indicate that converter slag fertilizer is a promising approach for the management of bacterial seedling rot of rice.
