Apple and Pear Scab (Venturia spp.) overwinters on dead leaves and fruit laying on the soil surface. In spring when temperatures increase, sooty black fungal patches on the dead tissue produce primary spores, called ascospores, which release into the air or splashing water droplets then infect young buds, leaves and fruit. One to two weeks later, secondary spores called conidia are released, causing new infections and renewing the cycle.