A vineyard drone with a multispectral camera shows canopy vigour across a whole estate in one flight, usually as an index such as NDVI. That is good for finding weak patches, irrigation faults and uneven ripening, and for planning selective harvests. It is less good at diagnosing disease from above: early downy mildew and powdery mildew show first on individual leaves and bunches, often under the canopy.
Close-range cameras on a tractor, a quad or a phone see those symptoms better, because they look at leaves and clusters from the side. Grape disease detection models trained on that imagery can flag likely mildew, botrytis and other visible symptoms. In both cases the honest output is a ranked list of places worth inspecting, not a diagnosis. Disease risk models that use weather data add the timing.