Plant Industry - Sweetpotato Weevil Program

Surveys

Field surveys.  NCDA&CS sets traps in sweetpotato fields in North Carolina to monitor for sweetpotato weevils from August to October.  Green Funnel Traps are used and set with a male-specific pheromone lure and a kill strip at a density of one trap for every 10 acres or minimum of two traps per field following the protocols established by the Southern Plant Board committee.  Traps are set and left in the field for three weeks, pulled and checked for weevils and the data collected using apps in mobile devices (tablets). Data collection using mobile technologies has greatly improved NCDA&CS efficiency in these survey programs.  In 2020, 12,411 traps were set in sweetpotato fields in NC (Table 1) and no weevils were detected.

Table 1.  Traps set in sweetpotato fields in North Carolina during the 2020 survey season

Storage and processing facilities.  The movement of sweetpotatoes from production areas within the state and from other states into NC is one of the most important pathways of introduction of sweetpotato weevils into NC.  Storage and processing facilities are monitored all year during the sweetpotato storage season.  Bucket traps (or Universal Moth Traps) are used because of their higher efficiency in trapping and retaining weevils.  Traps are set at a minimum of 2 traps per storage facility with one trap inside and one outside and, a maximum of 3-4 traps according to the size and complexity of the operations.

Micropropagation and research facilities.  Sweetpotato micropropagation facilities (greenhouses) are important to propagate virus indexed and disease-free material necessary for planting high quality sweetpotato cuttings in NC production fields.  These facilities are monitored seasonally following the micropropagation protocols.

To report a sweetpotato storage, processing, research facility, or production field without traps, please phone our toll-free number at 1-800-206-9333 or report by email: newpest@ncagr.gov

Specialty surveys.  Although the NCDA&CS does not want to discourage the general public from planting sweetpotato plants in their gardens, educational or demonstration plots, we strongly suggest you contact the Plant Pest Specialist (PPS) in your area to monitor your plot for sweetpotato weevils.  NCDA&CS PPS will set and service traps in these small operations at no cost to the public.

The green bucket trap (or Universal Moth Trap) is used to detect sweetpotato weevil in the NC quarantine zone.  These traps are used because of their higher efficiency in trapping and retaining weevils.  Traps are set at a minimum of 2 traps per storage facility with one trap inside and one outside and, a maximum of 3-4 traps according to the size and complexity of the operations.

Regulatory agencies in other states and/or countries require proof and certification that sweetpotatoes are sweetpotato weevil-free when shipped and moved into those areas.   Failure to comply with these regulations can result in the loss and/or destruction of shipments and economic losses for growers.  To facilitate this process, The NCDA&CS provide the necessary inspection services and certification cards to growers shipping sweetpotatoes to other areas where these conditions are required.  Contact your regional PPS to assist you with these services.  

How to help keep NC sweetpotato weevil-free:

If you are a sweetpotato grower:

• Purchase only certified and tagged sweetpotato weevil-free plants from known sources.
• Routinely track the current quarantine status of the sweetpotato weevil in North Carolina and other states in our web page.
• Do not move sweetpotatoes from known infested or quarantined areas in other states to NC.
• Report to the NCDA&CS Plant Industry Division any field without a sweetpotato weevil trap.  Check the NCDA webpage for updates in our state trapping program and contact your regional Plant Protection Specialist (PPS).  Traps are set at no cost to the grower.
• Control sweetpotato weevil hosts such as morning glory in the vicinity of your fields.
• Do not disturb any sweetpotato weevil trap and report any damaged trap to your regional NCDA&CS PPS. 
• Report sweetpotato acreage to your local Farm Service Agency (FSA) every year to allow NCDA&CS personnel to effectively trap all sweetpotato fields in NC.
• Implement effective sanitation measures in all aspects of operations especially related to growing or storage of sweetpotatoes.
• Request proper documentation from suppliers of sweetpotato plant material (inspection/certification) and maintain this information on file.

To report a sweetpotato storage, processing, research facility, or production field without traps, please phone our toll-free number at 1-800-206-9333 or report by email: newpest@ncagr.gov

For the general public:

• Although NCDA&CS do not want to discourage the general public from planting sweetpotatoes in their own gardens, it is recommended, to protect the industry in NC, not to do it.
• If you plant sweetpotatoes in your garden, demonstration plot, school, or any other setting, please contact your PPS to have him/her set a trap at no cost and monitor your plot.
• If you are conducting research with ornamental sweetpotatoes or sweetpotato plants, contact your regional NCDA&CS PPS to set a trap and monitor for sweetpotato weevils.

Contact your regional Plant Protection Specialist for more information on the program or if you have any questions or concerns.