Moura Vitor A S, Ferreira Larissa C, Resende Marcio F R, Xavier Katia V
Everglades Research and Education Center, University of Florida/IFAS, Belle Glade, FL 33430, USA.
Horticultural Sciences Department, University of Florida/IFAS, Gainesville, FL 32611, USA.
J Fungi (Basel). 2025 Jun 11;11(6):443. doi: 10.3390/jof11060443.
Tar spot, caused by , is an established maize disease in the Midwest of the United States but remains an emerging concern in Florida. While this pathogen can overwinter on plant residue, its survival in Florida's subtropical environment is not well understood. This study evaluated how environmental factors affect the germination of ascospores and stroma integrity. Symptomatic maize leaves were incubated under four conditions: Histosol soil (muck), Krome soil (rocky), 4 °C, and 23 °C. Extensive leaf decomposition occurred in both soil types, with most plant material degraded after eight weeks, while the stroma maintained its structure. Despite this, ascospore germination declined across all conditions. After eight weeks, ascospores incubated at 4 °C retained 25% viability, while those at 23 °C had the lowest germination (0.7%). Ascospores from leaves buried in soil exhibited low viability (1-6%), with no significant differences between soil types (p=0.9944). Weather analysis revealed that increased temperature reduced germination rates, while higher humidity enhanced them. These findings suggest that displays limited survivability under Florida-like conditions, with germination rates declining over time. Therefore, cultural practices such as tillage, already employed by corn producers in Florida, may be effective in reducing sources of inoculum.
由[病原菌名称未给出]引起的玉米煤斑病在美国中西部是一种常见的玉米病害，但在佛罗里达州仍是一个新出现的问题。虽然这种病原菌可以在植物残体上过冬，但其在佛罗里达州亚热带环境中的存活情况尚不清楚。本研究评估了环境因素如何影响子囊孢子的萌发和子座完整性。将有症状的玉米叶片在四种条件下培养：泥炭土（腐殖土）、克罗姆土（多岩石）、4℃和23℃。两种土壤类型中叶片均发生了广泛分解，大多数植物材料在八周后降解，而子座保持其结构。尽管如此，所有条件下子囊孢子的萌发率均下降。八周后，在4℃下培养的子囊孢子活力保留25%，而在23℃下培养的子囊孢子萌发率最低（0.7%）。埋在土壤中的叶片上的子囊孢子活力较低（1 - 6%），不同土壤类型之间无显著差异（p = 0.9944）。气象分析表明，温度升高降低了萌发率，而湿度升高则提高了萌发率。这些发现表明，在类似佛罗里达州的条件下，[病原菌名称未给出]的存活能力有限，萌发率随时间下降。因此，佛罗里达州的玉米生产者已经采用的诸如耕作等栽培措施可能有效地减少[病原菌名称未给出]的接种源。
