Spotted-wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), a vinegar fly of Asian origin, has emerged as a devastating pest of small and stone fruits throughout the United States. Tolerance for larvae is extremely low in fresh market fruit, and management is primarily achieved through repeated applications of broad-spectrum insecticides. These applications are neither economically nor environmentally sustainable, and can limit markets due to insecticide residue restrictions, cause outbreaks of secondary pests, and select for insecticide resistance. Sustainable integrated pest management programs include cultural control tactics and various nonchemical approaches for reducing pest populations that may be useful for managing D. suzukii. This review describes the current state of knowledge and implementation for different cultural controls including preventative tactics such as crop selection and exclusion as well as strategies to reduce habitat favorability (pruning; mulching; irrigation), alter resource availability (harvest frequency; sanitation), and lower suitability of fruit postharvest (cooling; irradiation). Because climate, horticultural practices, crop, and market underlie the efficacy, feasibility, and affordability of cultural control tactics, the potential of these tactics for D. suzukii management is discussed across different production systems.

The Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is a highly invasive species attacking a wide range of ripening soft-skinned fruits. A series of laboratory choice tests were conducted to determine whether different levels of rice vinegar affected attraction of Merlot wine to D. suzukii, as well as to compare attractiveness of two common fermentation food baits: wine–vinegar and yeast–sugar water mixtures. The relative attraction of various combinations was used to develop a bait whose effectiveness was tested in the field. In laboratory choice experiments, wine–vinegar (80:20, v:v, hereafter referred to as wine) was more preferred over a yeast–sugar water mixture (hereafter referred to as yeast) by D. suzukii. Combination baits, either a mixture of wine and yeast or a mixture of wine and a supernatant from the yeast (comboS), were significantly more attractive than each product alone. The two combination baits were equally attractive to D. suzukii, so were the yeast and its supernatant, suggesting that yeast supernatant could be used as a replacement for the yeast–sugar mixture currently used for trapping D. suzukii. The additive effect between wine and yeast supernatant in the field was not as profound as observed in the laboratory. In the field trial, numerically more male and female D. suzukii were captured in traps baited with comboS than those baited with the wine or yeast alone; however, significant differences were only found between the comboS and wine or between the comboS and yeast in some weeks over the period of the experiment.

Solid set canopy delivery systems (SSCDS) are a novel foliar agrochemical delivery system designed as an alternative for airblast sprayers in high density fruit production. This study tested the pest management potential, coverage, and chemical deposition of an SSCDS using commercially available microsprinkler components over the course of a growing season. Spray coverage and deposition for a representative airblast sprayer and SSCDS were evaluated using water sensitive paper and tartrazine dye, respectively. Foliar sprays for pest suppression were applied through both systems, and damage assessments were taken at the midpoint and end of the growing season. SSCDS sprays demonstrated similar levels of coverage on the adaxial leaf surface as airblast sprays, but significantly lower coverage on the abaxial surface. However, mean levels of foliar chemical deposition was generally higher in the SSCDS. Evaluations found minimal arthropod and fungal damage in both airblast and SSCDS treated plots compared to untreated trees. The SSCDS was shown to be a viable alternative to the airblast, with inherent advantages such as rapid application time and improved worker safety. Furthermore, higher deposition on SSCDS treated foliage supports the hypothesis that SSCDS provide a higher droplet capture rate in the canopy, with less off-target loss and drift than airblast sprayers.

A solid set canopy delivery system (SSCDS) has the potential to be an efficient spraying technique because it minimizes chemical drift and allows timely spray applications even under adverse field conditions. A conventional SSCDS, working as a hydraulic spraying system, is controlled manually. Such operation makes it labor and time intensive for spray application in larger orchards. Therefore, a new hardware and software design was implemented in this project for field-level automation of a conventional SSCDS. An electronic control system (ECS) and a spray control unit (SCU) were developed and integrated with an improvised conventional SSCDS. A graphical user interface (GUI) was developed to provide user inputs to the ECS for valve actuation-based decision making. The SCU consisted of a microcontroller, a relay board, and a radio frequency (RF) module assisting in actuation of the solenoid valves in the desired sequence with commands from the ECS. Integrated RF trans-receiver modules facilitated closed-loop wireless communication between the ECS and SCU. This technical note elaborates on the successful integration of the hardware and software to achieve SSCDS automation and functionality, as well as the performance evaluation in a vineyard. The results confirmed the envisioned triggering sequence and solenoid valve actuation for different operating stages of the SSCDS over 120 m loop length. Moreover, the automated SSCDS had no significant differences in spray volume or pressure along the loop up to 82 m. Overall, the proposed integration will aid in automating SSCDS-based spray operation for larger orchards. To validate such a setup, further studies are planned for a centrally located control station and spraying several adjacent plots at a time. Keywords: Agricultural automation, Electronic control system, Precision spray application, Solid set canopy delivery, Spray control unit, Wireless communication.

Optimally configured solid set canopy delivery systems (SSCDS) can provide adequate spray performance in high-density apple orchards with a minimized risk of off-target pesticide drift. SSCDS configured in a shower-down emitter arrangement have been reported to be the simplest and most economical system. However, existing off-the-shelf emitters used in shower-down configurations have resulted in minimal deposition in lower canopy zones. Therefore, this study was focused on the modifications of off-the-shelf emitters to obtain a desirable spray pattern for adequate spray deposition in all the canopy zones. The modifications include redesigning the impact plate of two existing micro-emitters. Field tests were conducted to evaluate the spray performance of SSCDS with the non-modified emitters (treatment: SD1 and SD3) and contrast the results with modified emitters (treatment: SD2 and SD4). While the treatments SD1 and SD3 had off-the-shelf emitters with swivel plate and static spreader, respectively, the treatment SD2 and SD4 had similar emitters with modified impactor plates. In each treatment block, the apple canopy was divided into six zones and sprayed with a 500 ppm fluorescent tracer solution. Mylar cards and water-sensitive paper samplers were placed on the adaxial and abaxial leaf surfaces in each canopy zone to quantify spray deposition and coverage, respectively. The SSCDS treatments retrofitted with modified emitters, i.e., SD2 and SD4, were observed to have uniform and numerically higher deposition and coverage compared to SD1 and SD3. The SSCDS treatment with modified static spreader (i.e., SD4) resulted in the highest overall spray deposition (1405.7 ± 156.4 ng cm⁻² [mean ± standard error]) with improved mid (1121.6 ± 186.9 ng cm⁻²) and bottom (895.6 ± 149.3 ng cm⁻²) canopy deposition. Overall, the proposed emitter modification assisted in improved SSCDS spray performances and may be a way forward toward large-scale emplacements of such systems.