Drone spraying for corn
Once corn is chest high, a knapsack sprayer is torture. A drone still gets in from above.

Fall armyworm
Fall armyworm attacks the whorl and spreads fast, so timing and coverage of the whorl matter. We set height and droplet size so the spray lands where it is needed.
Dryland and slopes
A lot of Indonesian corn grows on hilly dryland, in NTT, Sulawesi and southern East Java. Terrain following lets the drone hold a steady height above the crop when wind and weather allow.