The Use of Multiple Unmanned Aircraft Systems as a Swarm to Release Sterile Mexican Fruit Fly (Diptera: Tephritidae) Into South Texas Citrus Groves.

Mexican fruit fly Anastrepha ludens (Loew) (Diptera: Tephritidae) is a key economic pest of citrus and represents a quarantine issue along the United States and Mexico Border. In order to respond to this threat, the United States Department of Agriculture produces approximately 175 million sterile Mexican fruit fly pupae per week and releases approximately 150 million adult flies per week via conventional fixed wing aircraft. Unmanned aircraft systems (UAS) offer a novel means of releasing sterile insects aerially, can be deployed on short notice in rapid response scenarios, require a small footprint to operate, and offer an alternative means to releasing sterile insects to traditional manned aircraft. UAS, however, are currently limited in two key areas, range and payload capacity. Swarm technology, flying multiple UAS at once, may increase the utility of UAS by distributing payloads and release patterns across multiple UAS. In order to test the viability of swarm technology in the release of sterile insects we conducted multiple mark release recapture experiments over south Texas citrus groves during 2017, 2018, and 2019. The results of this study demonstrate improved release rates from 89.9% (n = 5) of flies released with ca. 0.64% recapture during 2018, to 98.2% (n = 6) released with ca. 0.74% recapture during 2019. These results demonstrate that swarm technology is a viable technique for increasing aerial release capacity and flexibility of sterile insect technique (SIT) programs.

A Special Collection: Drones to Improve Insect Pest Management.

The Special Collection Drones to Improve Insect Pest Management presents research and development of unmanned (or uncrewed) aircraft system (UAS, or drone) technology to improve insect pest management. The articles bridge from more foundational studies (i.e., evaluating and refining abilities of drones to detect pest concerns or deliver pest management materials) to application-oriented case studies (i.e., evaluating opportunities and challenges of drone use in pest management systems). The collection is composed of a combination of articles presenting information first-time published, and a selection of articles previously published in Journal of Economic Entomology (JEE). Articles in the Collection, as well as selected citations of articles in other publications, reflect the increase in entomology research using drones that has been stimulated by advancement in drone structural and software engineering such as autonomous flight guidance; in- and post-flight data storage and processing; and companion advances in spatial data management and analyses including machine learning and data visualization. The Collection is also intended to stimulate discussion on the role of JEE as a publication venue for future articles on drones as well as other cybernectic-physical systems, big data analyses, and deep learning processes. While these technologies have their genesis in fields arguably afar from the discipline of entomology, we propose that interdisciplinary collaboration is the pathway for applications research and technology transfer leading to an acceleration of research and development of these technologies to improve pest management.

Operational Parameters for the Aerial Release of Sterile Codling Moths Using an Uncrewed Aircraft System.

The codling moth is a serious pest of apples in most regions of the world where this fruit is produced. The sterile insect technique is one strategy used to control this pest and is employed as part of an area-wide integrated pest management program for the codling moth in British Columbia, Canada. Modified fixed wing aircraft are the most common method for the release of sterile insects in large area-wide pest management programs. However, aerial release with a full-size aircraft can be prohibitively expensive. We evaluated the use of small, uncrewed aircraft systems (UASs) for the release of sterile codling moths. Sterile codling moths released from greater altitudes were more broadly distributed and drifted more in strong winds, compared to those released from lower altitudes. Most of the released insects were recaptured in a 50 m wide swath under the release route. Recapture rates for aerially released insects were 40-70% higher compared to those released from the ground. UASs provide a promising alternative to ground release and conventional aircraft for the release of sterile codling moths.

Toward Implementation of Mosquito Sterile Insect Technique: The Effect of Storage Conditions on Survival of Male Aedes aegypti Mosquitoes (Diptera: Culicidae) During Transport.

Sterile insect technique (SIT) is a promising, environmentally friendly alternative to the use of pesticides for insect pest control. However, implementing SIT with Aedes aegypti (Linnaeus) mosquitoes presents unique challenges. For example, during transport from the rearing facility to the release site and during the actual release in the field, damage to male mosquitoes should be minimized to preserve their reproductive competitiveness. The short flight range of male Ae. aegypti requires elaborate release strategies such as release via Unmanned Aircraft Systems, more commonly referred to as drones. Two key parameters during transport and release are storage temperature and compaction rate. We performed a set of laboratory experiments to identify the optimal temperatures and compaction rates for storage and transport of male Ae. aegypti. We then conducted shipping experiments to test our laboratory-derived results in a 'real-life' setting. The laboratory results indicate that male Ae. aegypti can survive at a broad range of storage temperatures ranging from 7 to 28°C, but storage time should not exceed 24 h. Male survival was high at all compaction rates we tested with a low at 40 males/cm3. Interestingly, results from our 'real-life' shipping experiment showed that high compaction rates were beneficial to survival. This study advances key understudied aspects of the practicalities of moving lab-reared insects into the field and lies the foundation for further studies on the effect of transport conditions on male reproductive fitness.