(1823) Botryosphaeria dothidea is a plant pathogen that causes the formation of cankers on a wide variety of tree and shrub species.
[3] Even so, B. dothidea has since been identified on a number of woody plants—including grape, mango, olive, eucalyptus, maple, and oak, among others—and is still expected to have a broad geographical distribution.
[3] While it is best known as a pathogen, the species has also been identified as an endophyte, existing in association with plant tissues on which disease symptoms were not observed.
[8] Recent analysis has confirmed the presence of B. dothidea, along with other Botryosphaeria species, on Malus sp..[9] Cankers and other dead wood and bark tissue, as well as mummified fruit (fruit infected by the pathogen and remaining in the orchard) serve as sources of primary and secondary inoculum.
[7] Using spore traps for airborne spores and funnel traps for rainwater, Sutton (1981) determined that, while both conidia and ascospores of B. dothidea are released from infected pruning waste (dead wood) during rainfall events and conidia are predominantly water-dispersed, ascospores spread in both air and water.
[11] While the International Botanical Congress recently emended the International Code of Nomenclature for algae, fungi, and plants to state that one fungal species should be called by one name,[12] the sexual (teleomorphic) and asexual (anamorphic) stages of single fungal species have often been called by different names.
[3][11] Like other members of the Dothideomycetes, the sexual stage of B. dothidea has bitunicate asci, which are borne in cavities ("ascomata") formed through a process known as "ascolocular development".
Like other species in the order Botryosphaeriales, B. dothidea ascomata have "multilayered dark brown walls" and contain septate pseudoparaphyses which are transparent or translucent (hyaline).
[11] Microconidia are small, asexual spores that often act as male gametes or gametangia (spermatia) in a process of cytoplasmic fusion (plasmogamy)[16] According to a key provided in Phillips et al. (2013), B. dothidea can be distinguished from six other members of the genus by conidia that are typically longer than 20 μm, have a length to width ratio greater than 4.5, and occur on hosts other than Vaccinium species.
[3] These conidia are "narrowly...or irregularly fusiform," have thin walls, and are generally transparent or translucent (hyaline) and aseptate but sometimes form up to two septa and/or darken when they are older.
Differentiating between species based on morphology depends on observing multiple samples, to get an idea of prevailing character states, and doing so at the appropriate developmental stage.