Panel 5: ascomycetes/spores

Direct microscopy of leaf surfaces and ascospore-capture techniques revealed that 91 to 98% of leaf-blade surface area (absent high invertebrate mycophagy) was occupied by patches of ascomycete sexual structures (ascomata) of one or more of three predominant species (Phaeosphaeria spartinicola [PS], Mycosphaerella sp.2 [MY], and P. halima [PH]). PS and MY were very consistently actively present (78% of all spores captured). Rates of ascospore release were uniform over the 3 years, but rates for oldest leaf blades were only 30% of those for younger blades; maximum expulsion rates were found in spring or winter (88 to 182 spores cm^-2 leaf abaxial area h^-1 of leaf wetness).

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Spore sizes: PS, about 11 µm wide; PH, 7 µm; MY, 6 µm; 4clt, 8 µm