It depends on how hot your compost gets. Most fungal spores will be killed by temperatures of 140 to 160 degrees Fahrenheit. Unless you can heat the pile to at least 140 degrees, it is best to either burn, bury, or dispose of the fallen fruit and leaves. Having said that, while removing diseased fruit and leaves will limit the spread, unless you remove the other host you will continue to have issues with pear rust in the future (some years may be more severe than others). There are two main rust diseases of pears in Oregon, Pacific Coast Pear Rust (Gymnosporangium ibocedri) and Trellis Pear Rust (G. sabinae). Rust fungi typically have two different hosts, the primary host (ex. your pear tree) that will display severe symptoms and a secondary host (ex. your neighbor’s incense cedar or juniper) which may only display minor symptoms and effects. The best control is to remove the alternate host that is within a 1,000-foot radius of the tree, however, in urban environments this may not be an option if the hosts are in neighboring yards. There are no chemicals registered for home use for either species of rust, so if you are considering a pesticide, your best option is to hire a company that is licensed to apply a commercial pesticide (see: https://solvepestproblems.oregonstate.edu/index.php/pesticide-information/hire-pest-control-company). Removing and destroying infected leaves, stems and fruit to limit the spread, collecting and destroying fallen fruit beneath trees, and of course removing alternate hosts when practical are the best options for home gardeners.