germ tube or indirectly using an appressorium, thus initiating a new infection. Shortly after penetration, light-green, irregularly shaped lesions develop on infected foliar tissue and gradually darken, expand, and pucker as the infection progresses. Lesions on fruit are black or brown and irregularly shaped, with older fruit lesions causing the underlying tissue to become dry, corky, and eventually disfigured by splitting. Within 10 days of infection, asexual conidia will develop on the darkened lesions and allow for the establishment of secondary infections in healthy leaf and fruit tissue. Under optimal conditions, this cycle may repeat every 1–2 weeks during the growing season. At the end of the season, heavily-infected fruit and foliage fall from the canopy, allowing for the development of pseudothecia, which serve as a source of primary inoculum for the next spring. Predicting infection First developed in 1944 by American plant pathologist, W.D. Mills, a Mills Table predicts the likelihood of an apple scab infection developing based on the average temperature and the number of hours of leaf wetness that the host plant is exposed to. This prediction system has been rapidly adopted in both Europe and North America, where apple growers use it as an early warning system for new infections, allowing them to apply preventive fungicides when appropriate. Several revisions have been made to the Mills Table since its creation. The most notable revision was made in 1989 by plant pathologists William MacHardy and David Gadoury, who determined that ascospores required 3 hours less than originally calculated in order to establish a new infection. While other methods of prediction include ascospore maturation models and leaf orchard leaf canopy models, the Mills Table, combined with electronic weather monitoring, remains the most-widely used tool for predicting apple scab infection periods. Management of apple scab Cultural controls Cultural controls may be used as a first step when seeking to reduce the incidence of new infections. These practices include cleaning leaf litter from the base of previously-infected trees, as well as removing infected woody material from the canopy when performing annual pruning. Doing so will reduce the amount of primary inoculum in the spring and subsequently delay the establishment of the disease. Furthermore, regular pruning will improve air flow and light penetration in the canopy, which ultimately inhibits the development and spread of disease. Another aspect of cultural control is water management. As water triggers ascospore release and promotes germination