Development of an Automated Precision Spraying System for Sustainable Pest Management in Apple Orchards

Pesticides are used to control diseases, weeds, and pests which pose a serious threat to agricultural crop production. Pesticide application using conventional sprayers wastes a significant amount of agrochemical and potentially causes human health hazards and environmental contamination. To reduce pesticide use and risk to health and the environment, the proposed research will be developing an automated precision spraying system that can apply agrochemicals as needed to apple orchard trees considering orchard terrain variabilities and weather conditions. Three main objectives will be pursued for this research. First, the canopy foliage density information will be analyzed to measure appropriate tree architecture appraising orchard terrain conditions using a laser sensor, inertial measurement unit, and global navigation satellite system. In the second objective, air-blast sprayer fan and nozzles will be automated to control the spray volume during spraying according to canopy density information and real-time weather condition data. In the third objective, the efficacy of the developed precision sprayer will be evaluated for apple scab and codling moth pest management. Finally, the performance of the proposed system will be compared with existing sprayers. Since appropriate tree canopy structure will be considered for spraying, it is anticipated that the proposed automated precision spraying system will significantly reduce the excessive use of pesticides compared to the conventional sprayers for pest management. Based on the economic analysis among sprayers, this study will identify which spraying technique could lead to the highest profit for the apple growers.

Project objectives from proposal:

The major aim of this research is to develop an automated precision spraying system for pest management in the orchards considering the different tree canopy structures and orchard terrain conditions of Pennsylvania. The research project will be focused on the following objectives:

Development of LiDAR-guided sensing technology for assessing tree canopy density of different tree architectures

A LiDAR-guided sensing system will be developed to accurately measure the canopy density of an individual tree. An individual tree will be divided into six sub-sections due to having six nozzles on each side of the sprayer unit. Then the canopy density of each section will be calculated. An Inertial Measurement System (IMU) will be used to record the posture of the LiDAR system to perform necessary adjustments of the canopy information as well as tree orientation. A Global Navigation Satellite System (GNSS) system will be used to track the geo-reference of the trees with canopy density and terrain information. The combination of the tree canopy and terrain information will be analyzed to provide guidance for the control of the precision sprayer. Real-time tests will be conducted to evaluate the system performance before integrating it into the spraying unit.

Automation of nozzles and air-blast sprayer fan for target spraying

An automatic system will be developed aiming to conduct target spraying using adjusted tree canopy density information and real-time weather data. Both the nozzle and air-blast fan speed will be controlled automatically during spraying. The nozzles will be controlled by using the tree canopy information and the air-blast sprayer fan speed will be controlled by using both tree canopy density, and real-time weather information (e.g., temperature, humidity, wind speed, and direction, etc.). Fan speed control is important because it is responsible for pulls air in and redistributes it upwards into the tree canopy for reaching the spray droplet on target.

Performance evaluation of the developed precision spraying system for the efficacy of field control of disease and pest

The developed precision spraying system will be tested in the field to evaluate its efficacy for the apple scab and codling moth control for the apple trees. The robustness of pest control by this newly developed spraying system will be compared with conventional methods, as well as the working efficiency and overall chemical usage.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.