Status of the biological control of air potato in Louisiana after six years from initial agent release

Air potato (Dioscorea bulbifera L.) is an invasive vine that has negatively affected natural and urban landscapes by displacing native species and reducing biodiversity in the southeastern USA. Field releases of the biological control agent, Lilioceris cheni Gressitt and Kimoto (Chrysomelidae), were initiated in Florida (2012) and later in Louisiana (2016) to help manage air potato. The main goal of my research was to assess current distribution and efficacy of L. cheni six years after initial releases in Louisiana. Release sites were monitored in summer and fall of 2021 and 2022, and field releases were conducted in new sites where no signs of beetle were found. Maps were developed to show location of beetle releases and presence or absence over time. In addition, data was collected using 1 m² quadrats to assess air potato cover and beetle damage in field sites. Results showed that L. cheni has established in most release sites and dispersed to new sites in Louisiana. However, extreme weather events such as hurricanes or unusual colder winters, negatively affected beetle overwinter survival in some sites. Few air potato patches were identified with no signs of beetles, and new releases were conducted in those sites. Results will be discussed in relation to the efficacy of this biological control program in Louisiana.