Development of a sensor-controlled sprayer for applying low-volume bait treatments

Fruit flies that are very important pests on a large number of crops, can be controlled efficiently using low-volume applications to deposit large droplets of insecticidal bait on the exterior of the crop canopy. To meet these requirements a sensor-controlled sprayer was developed, consisting of a hydraulic system that was fitted with air induction nozzles, an ultrasonic sensor and a control unit with display and navigator keys. This sprayer was designed to apply low spray volumes as very coarse spray droplets. The nozzle with the coarsest spray was an Al11003 operated at 0.1 MPa. The sensor recognised differences in crop canopy so could adapt the application to different citrus crop systems in commercial orchards. The sensor-controlled sprayer was tested measuring the size of deposited droplets on the target and observing its performance on the field. Coverage was predominently on the outer canopy zone with little inside the canopy. This sprayer provides an alternative to cover treatments, not only from environmental but also from economic reasons. (C) 2008 Elsevier Ltd. All rights reserved.