Sugarcane and cassava — what to adjust when spraying tall crops by drone

Sugarcane and cassava grow tall and have a dense canopy from mid to late season, which changes the conditions for drone spraying considerably.

The main problem is canopy penetration

When the upper leaves are dense, most droplets are caught in the top layer and do not reach the lower layers or the base of the plant, where some pests live.

Lower the flight height as far as is safe, so the downwash is still strong enough when it reaches the canopy.
Slow down, so the downwash has more time to work on each part of the crop.
Choose a suitable droplet size. Droplets that are too small are caught on the topmost leaves; droplets that are too large run off to the ground before spreading.

In very tall crops with a very dense canopy, aerial spraying has real limits. Jobs that need the product to reach the base of the plant or the soil surface under the canopy may need other methods as well. Saying that drones can do every job at every stage gives hope that does not match reality.

Early in the season when the crop is not yet tall, spraying is thorough and very fast.
When the field cannot be entered because the soil is wet or the crop is too tall for vehicles, conditions in which other tools cannot work at all.

Tall crops narrow the gap between the propellers and the top of the crop. Watch out for snagging, and for the radar misreading an uneven canopy. Walk the field and check the real height at several points before setting up.

Plan from the start which jobs will use a drone and which will use other methods, rather than trying to use the drone for every job. Overall it will work better and cost less.
Important note
This article explains general principles. It is not a recommendation for any specific chemical. Suitable mixing rates and timing differ by substance, crop, growth stage and field conditions. Always treat the product label as the authority, and ask our staff or an agricultural specialist before deciding.