Orchard training and pruning should allow good airflow and light penentration and allow trees to dry rapidly and reduce the risk of mouldy core. At harvest apples that are riper than usual should not be picked as these have a high chance of having mouldy core.
Wet core can be solved by only drenching post-harvest if necessary and adopting strict hygiene measures in the drenching operation to prevent the build up of mud, fungal spores and other debris in the drenching solution.