Sweet Potato Weevil

Cylas formicarius

Sweet Potato Weevil is a species-level regulated root and stem pest associated with sweet potato and morning-glory relatives. Tunneling creates bitterness, cracking, decay, and unmarketable roots. Adult and larval injury are evaluated separately.

Identification

Adults are antlike with a blue-black abdomen, reddish thorax, and long snout. Larvae tunnel inside vines and storage roots. Inspect vines and roots for punctures and galleries, use approved pheromone traps, and dissect suspect roots. Root larvae and internal feeders usually require specimens.

Symptoms / Signs

Tunneling creates bitterness, cracking, decay, and unmarketable roots. Fresh larval injury includes live grubs, tunnels, root pruning, or internal feeding. Old scars do not prove activity.

Life Cycle / Process

Sweet Potato Weevil undergoes complete metamorphosis. Eggs are placed in or on the marketable host tissue, larvae feed internally, and pupation occurs in the host or soil according to the species. Adults are the exposed stage for monitoring before oviposition.

Prevention

Inspect incoming stock above and below ground. Remove culls, volunteer hosts, spilled seed, and infested root balls where relevant to Sweet Potato Weevil.

Management / Control

Use certified slips, destroy culls and volunteer morning glories, maintain sanitation, and follow quarantine requirements. Recheck adult and larval injury separately.

Procedure Steps

1. Inspect the relevant buds, pods, fruit, stems, or roots for punctures. 2. Dissect a representative sample for internal stages. 3. Collect and identify adults before treatment. 4. Remove infested produce, drops, culls, and reservoirs. 5. Target adults before oviposition only with current crop guidance. 6. Resample the next susceptible crop cohort. 7. Close the Sweet Potato Weevil incident after fresh injury declines.

Safety Notes

Protect food, seed, packaging, workers, and Myco-Patrons during inspection and treatment. Use tamper-resistant placements where baits or traps are necessary, and keep pesticides off food-contact surfaces. Structural or termite work may require a licensed Florida pest-control operator.