Foliar
/ˈfəʊliər/
Definition 1 of 2
Pro Tip 1/3Not Animal-Related
Foliar always involves plant leaves, never animals. 
Vets don't deal with foliar issues, as they don't pertains to animals.
Pro Tip 2/3Technical Term
Foliar is mostly used in scientific or agricultural contexts. 
The researcher documented the foliar structure under the microscope.
Pro Tip 3/3Negative Connotation
'Foliar disease' often implies plant health problems. 
The crop's yield was reduced due to a severe foliar disease.