No reports of loss of pathogenicity of agar media. C. orbiculare has a perfect stage Glomerella cingulata var. Old cultures under mineral oil do not form acervuli or spore masses, and are not good for inoculations. After repeated mass transfer of spores, cultures of race 1 sporulate poorly. Retrieve a culture from storage or 'single spore' the low sporulating culture.
Single spores segregate mycelial type and sporulating type.
Add a few ml of distilled water to a 6-9 day old culture and shake vigorously for 10 seconds on a Vortex mixer to dislodge the spores. Wash the spores by centrifuging at 3,000 rpm for 10 min. Discard the supernatant. Resuspend the pellet in distilled water. Spray inoculum on upper surface of one cotyledon with a painter's air brush at 5-10 psi air pressure.