Q.lime trees
I have a disease of limes that is spreading to other trees, blighting all the fruit. The limes from new baby limes to 4-5 inch long limes are dry, tan colored with leathery browning over the skin. When the fruit is cut open, it looks pulpy green normal, but juice is bitter. The leaves will fall off when fruit is pulled off.
Certified GKH Gardening Expert
The fact that the lime juice is bitter could indicate citrus greening disease, described here:
http://www.citrusalert.com/about-citrus-greening/
Check whether this is present in your state.
Other than the leaves falling off, is there any visible damage or discoloration on leaves? Browning on citrus rinds can be caused by some diseases and some types of insect damage from sucking insects like thrips and scales. Many of these can also affect leaves:
https://www.gardeningknowhow.com/edible/fruits/citrus/controlling-citrus-scale.htm
https://www.gardeningknowhow.com/edible/fruits/citrus/controlling-citrus-thrips.htm
http://ipm.ucanr.edu/PMG/C107/m107bpfruitdis.html
http://ipm.ucanr.edu/PMG/C107/m107bpfruitinvert.html