I'm not sure what you're asking here, are you asking for suggestions on the best tag to use?
If there are no existing tags for crop dusting, it suggests that so far most people don't need one. If you disagree you're always welcome to tag the questions yourself with whatever tag you think is best. If other people then start using a different tag, we can eventually discuss it on meta and resolve it with synonyms. But right now there's nothing to show that a) people want the tag (apart from you!), and b) if they did want it, what words(s) they would use to tag the questions.
It looks like the terminology in this area is a bit unclear anyway:
Aerial application, or what was formerly referred to as crop dusting,
involves spraying crops with crop protection products from an
agricultural aircraft. Planting certain types of seed are also
included in aerial application. The specific spreading of fertilizer is also known as aerial topdressing in some countries.
Aerial application operations consist of agricultural spraying and
dispensing of materials from low-flying aircraft. This can include
insecticides and pesticides, herbicides, fertilizers, defoliants,
seed, fire control substances, and other potentially toxic materials.
[...] Commonly referred to as crop dusting in the United States, this
includes fire fighting aircraft and what is termed top dressing in New
Zealand and Australia.
Those definitions are close but not exactly the same: the FAA includes firefighting. Personally, I'd rather wait and see how people really use the tags (if at all) before trying to guess what the best synonyms would be.
And since "aerial application" is rare but "crop dusting" is well known, as your searches showed, I'm not sure if it's really helpful to push the rarely used term as the best tag. YMMV.