The rule of thumb is that the fruit on the overhanging branches belongs to the tree owner. Picking the fruit may not be so simple. Ownership of the fruit does not give your neighbor any right to trespass onto your property to pick the fruit.
The law in Minnesota on this subject is not clear cut. Courts would probably weigh your right to keep trespassers out of your yard against the owner’s right to harvest the fruit. The balance may tip in favor of your neighbor, if she owns an orchard and depends on the fruit for her livelihood.
The law is also unclear on the issue of fallen fruit. Once it has fallen, the fruit’s value diminishes. It has become, for all practical purposes, “tree debris.” You should be able to use or dispose of the fruit, if your neighbor says nothing about wanting it.