Undergraduate Researcher University of Georgia Fort Myers, Florida
Invasive species have become more common and more calamitous with the rise of globalization and international supply chain networks, threatening agroecosystems as well as native biodiversity worldwide. The yellowmargined leaf beetle, Microtheca ochroloma (Stal), recently invaded the American Southeast and has rapidly emerged as the most devastating pest of many organic crucifer crops including turnip, bok choi, and napa cabbage. As an understudied newcomer to North American ecosystems, it is largely unknown whether M. ochroloma faces any predatory pressure in its invasive range. The object of this research is to identify potential predators of M. ochroloma native to North America through both field observation and genetic surveillance, enabling development of predator-based biocontrol strategies. During the summers of 2018 and 2021, we surveyed predators and M. ochroloma on a variety of susceptible Brassica rapa cultivars and developed a shortlist of predators most commonly associated with M. ochroloma. Additionally, nearly 400 field predator specimens were collected and preserved so that their gut contents can be assayed for M. ochroloma DNA, utilizing recently generated primers. While our field data suggests pink-spotted lady beetles and big-eyed bugs as potential predator controls, molecular gut-content analysis will validate trophic links between M. ochroloma and predators observed in the field. Identifying key native predators will help in the development of biocontrol regimens to bolster these predator populations and help farmers turn the tide in their battle against this novel pest.
