The infection process requires free water on the leaf surface and temperatures between 20-32 C. Infection proceeds rapidly during warm wet weather. Acervuli consist of orange masses of conidia. Races 1 and 2 available. 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.