Citrus black spot, caused by Phyllosticta citricarpa, is characterized by fruit blemishes and premature fruit drop, resulting in significant economic losses in summer rainfall areas. The pathogen forms both conidia and ascospores during its life cycle. However, the occurrence of these spores and their contributions to infection of fruit in field conditions are not well understood. Our research using direct leaf litter monitoring and volumetric spore trapping in Queensland orchards revealed that pseudothecia and ascospores in leaf litter as well as trapped ascospores had low abundance, while pycnidia and conidia were highly abundant. Both P. citricarpa and endophytic Phyllosticta spp. were identified, with P. citricarpa being dominant. In replicated field trials, we determined that infection of Imperial mandarin fruit by P. citricarpa occurred from fruit set until week 20 of fruit development, with the key infection events taking place between weeks 4 and 16 in Queensland subtropical conditions. These results demonstrate that protecting fruit during weeks 4 to 16 significantly reduced P. citricarpa infection. We found no significant correlation between the disease incidence in fruit and P. citricarpa conidial abundance in leaf litter or ascospore abundance measured by volumetric spore trapping. Therefore, it is suggested that inoculum sources in the tree canopy other than those detected by spore trapping and direct leaf litter monitoring may play a major role in the epidemiology of citrus black spot. Improved knowledge regarding epidemiology of P. citricarpa and an understanding of propagules causing infection may aid in development of more effective disease management strategies.

柑橘黑斑病（Phyllosticta citricarpa）引起的柑橘黑点的特征是果实有瑕疵和果实过早落下，导致夏季降雨地区的重大经济损失。病原体在其生命周期中同时形成分生孢子和子囊孢子。然而，这些孢子的发生及其在田间条件下对果实感染的贡献还没有被很好地理解。我们在昆士兰州果园中使用直接的叶子凋落物监测和体积孢子诱捕的研究表明，叶子凋落物和被诱捕的孢子孢子中的假甲虫和子囊孢子的丰度较低，而钩虫和分生孢子的含量很高。无论P. citricarpa和内生叶点属。被鉴定为柠檬酸假单胞菌占主导地位。在重复的田间试验中，我们确定柑桔P. trictricarpa感染了国语普通话果实，从坐果期到果实发育的第20周，关键的感染事件发生在昆士兰州亚热带条件下的第4周至第16周之间。这些结果表明，在第4至16周内保护果实可显着减少柠檬酸假单胞菌的感染。我们发现水果和柠檬假单胞菌的发病率之间没有显着相关性落叶分生孢子的丰度或子囊孢子的丰度通过体积孢子捕获法测定。因此，建议除了通过孢子捕获和直接落叶监测而检测到的树冠中的接种源可能在柑桔黑斑的流行病学中起主要作用。关于柠檬酸假单胞菌的流行病学知识的提高和对引起感染的繁殖体的了解可能有助于制定更有效的疾病管理策略。