Listronotus sparsus (Say), an emerging weevil pest of celery and parsley in southern Florida

An increase in unusual insect injury has been observed in organic and conventional celery and parsley fields in southern Florida. This injury consists of weevil larval tunneling through the petioles, crowns, and roots. Weevil adults collected in celery fields, as well as adults reared from larvae infesting celery plants were identified as Listronotus sparsus (Say), which is a relatively widespread species that has not been reported as a crop pest. Our observations suggest that this weevil exhibits behavior comparable to that of carrot weevils, L. oregonensis and L. texanus, which are serious pests of Apiaceae crops in the Great Lakes region and Texas, respectively. Thus, this weevil might represent a significant threat to celery, parsley, cilantro and carrot production in Florida. A celery field experiment compared the efficacy of oxamyl, cyantraniliprole, chlorantraniliprole, clothianidin, and novaluron for weevil control. Post treatment injury and number of larvae suggest that oxamyl suppresses weevil infestations. Celery sentinel plots were established to study the biology of the weevil and its seasonal dynamics. Plots were sampled weekly, showing that weevils started laying eggs three weeks after transplanting, Egg and larva incidence suggest that the weevil infests plants throughout the crop season. Scouting efforts in Palm Beach and Hendry counties are continuing to identify weevil infestations in crop hosts in the Apiaceae family such as celery, parsley, carrot, cilantro, and dill. This work was the first effort to identify this emerging weevil pest, study its biology, provide management information, and involve stakeholders in an educational program.