The supplementary anamorph phase Asteromella brassicae produces conidia through its asexual reproduction, however these spores are not confirmed to cause disease in host plants.

[1] Mycosphaerella brassicicola is common among a variety of crops within the genus Brassica and has been historically noted on Brussels sprouts, winter cauliflower, and cabbage.

[3] The fruiting bodies require moisture to facilitate their reproduction and tend to form after a period of 100% relative humidity lasting at least four days.

The ring lesions produced by ascospore infection will terminate at the veins of leaves, at times restricting the characteristic circular nature of the signs of Mycosphaerella brassicicola.

Poor soil drainage can contribute to Mycosphaerella brassicicola proliferation through allowing for the high levels of moisture required for the ascospores to infect their host.