Traditionally, aerial pesticide spraying worldwide has been done using conventional fixed-wing aircraft or helicopters with a pilot onboard. However, this is changing fast. Small, remotely piloted aircraft are being used to apply pesticides around the world, especially in East Asia (mainly China, Japan, and South Korea). For example, about 2,800 unmanned helicopters were registered as of March 2016 in Japan, spraying more than a third of the country’s rice fields. Although rice is the main crop treated with spray drones in Japan, use of drones to treat other crops such as wheat, oats, soybean, and other crops has been steadily increasing. According to one report, 30% of pesticide spraying in South Korea is done using drones.
Korea and Japan have used drones for years—mainly the single-rotor, remote-controlled helicopter. Their use of multi-rotor drones is much more recent in contrast to China who have experienced the most significant increase in use of multi-rotor drones for spraying pesticides. The first multi-rotor spray drone in China was manufactured in 2009. In 2016, 200 companies manufactured and sold over 169 different models of multi-rotor spray drones with total sales exceeding 10,000 units that year. China drone manufacturers continue to introduce one or two new models of their own annually, often with significant upgrades. Currently, China is by far the greatest user of small, multi-rotor drones. In 2020, China sprayed 64 million acres using small drone application technology. The next year (2021), acreage of cropland sprayed by drones increased to 153 million acres. Their drone crop spraying includes not only insecticides and fungicides, but also herbicides and defoliants. Although China’s spray drone use started in 2015, usage of drones to spray pesticides in all other countries as of 2024 only equals a small percentage of China’s current spray drone use. According to data from the country’s National Agro-Tech Extension and Service Center (NATESC), China had about 4,000 crop-protection drones in 2016. In 2021, more than 120,000 drones were used to spray pesticides on over 175.5 million acres of farmland across the country, and there were over 200,000 agricultural-drone pilots.
Using drones for spraying pesticides is attractive for many countries around the world mainly for five reasons: (1) The topography or soil conditions do not allow the use of traditional ground sprayers or conventional agricultural aircraft, (2) airplanes and helicopters are not available or are too expensive to use. (3) drones more efficiently spray small, irregular-shaped fields which are the norm in most countries, (4) spray drones significantly reduce the risk of applicators being contaminated by the pesticides (backpack sprayers, which pose significant health risk to their users, are the most preferred spray equipment in many countries), and 5) lack of stringent regulations to operate spray drones.
In contrast, drone spraying is in its infancy in the United States because many of the reasons for adoption of drones in other countries don’t apply to US agriculture. We have large fields which makes use of sprayers with huge booms reaching 120 ft in length economically feasible. For example, the average area of agricultural land per farm entity in Japan is less than one-sixtieth of the average farm in the USA. The terrain in where agriculture is practiced in the USA is relatively flat conducive to using conventional manned aircraft or ground sprayers with large booms. However, the interest in using drones to spray pesticides is steadily increasing. According to the data provided by a leading company in the USA providing spray drone services, the number of acres they sprayed with drones increased from only 1,000 in year 2019 to near 200,000 acres in 2023. Ohio is ranked #2 among the top 10 States (slightly behind Iowa) in acres sprayed by this leading spray drone company. Major reasons for this increase include: 1) more frequent occurrence of wet grounds in the spring which prohibits operating traditional large ground spray equipment, 2) reduction in the number of conventional manned aircraft making the timely application of pesticides more difficult when ground conditions require aerial application, 3) recent technological advancements in spray drone designs are allowing operators cover larger areas per hour of operation, 4) FAA is approving exemption requests (such as maximum payload capacity, and night spraying) coming from drone operators at a much faster pace, and 5) cost of using spray drones compared to ground spraying is becoming extremely competitive and even lower in some areas.
A newly-revised OSU Fact Sheet (FABE-540) entitled “Drones for Spraying Pesticides—Opportunities and Challenges” expands on why spray drones may be the choice for aerial spraying, the challenges that reduce their usage by pesticide applicators, recent developments in spray drones, operating characteristics of spray drones, and best spraying practices when using drones. This publication is available free of charge from Ohio State University Extension at https://ohioline.osu.edu/factsheet/fabe-540