Meteorological and flight altitude effects on deposition, penetration, and drift in pineapple aerial spraying

It is difficult for the handheld/backpack or ground machinery to spray pineapple plant fields because the plant profile is relatively inaccessible. In this situation, unmanned aerial vehicles (UAVs) are a good choice for easy access and no physical damage to the crops. Aerial spray quality and optimum application parameter settings can be influenced by many factors such as UAV type, UAV operating parameters, meteorological conditions, crop growth period, and pest species. The objective of this study was to investigate the effects of different meteorological conditions and UAV operating height on the spray application in pineapple fields. There were five treatments involving three UAV operating heights. Mylar cards, water‐sensitive papers, and airborne concentrations of spray were sampled at various locations from −10 to 50 m downwind of the edge of the sprayed blocks. The results indicated that as the wind speed increased, the swath location was displaced 2 to 4 m, the percent area coverage uniformity changed along with the spray penetration capacity, and the 90% of total measured drift distance varied from 3.7 to 46.5 m. The test results again proved that droplet size and wind speed were significant factors in spray transport and impacted the UAV spray quality.