Management of the Guava Root Knot Nematode in Sweet Potatoes

— Written By

Lina Quesada-Ocampo | NC State University | 10/12/2018

In recent years, some North Carolina sweet potato growers have found Meloidogyne enterolobii, also known as the guava root knot nematode, affecting their crop. These reports have prompted previous alerts from the North Carolina Department of Agriculture & Consumer Services and the NC State Vegetable Pathology Lab, as well as research regarding chemical control methods. Management information available to date is described in our sweet potato root knot nematode fact sheet.

This root knot nematode was first reported infecting cotton and soybean in North Carolina in 2013, and has also been officially reported in Puerto Rico (1983) and Florida (2012). Recent reports of M. enterolobii from Louisiana have resulted in the enactment of an internal quarantine from the North Carolina Department of Agriculture & Consumer Services to help prevent further spread of this nematode. Following this action, the Louisiana Department of Agriculture and Forestry also enacted an external quarantine for Florida, South Carolina, and North Carolina to restrict entry of items that can potentially spread M. enterolobii.

The North Carolina internal quarantine states that sweet potato seed roots need to be inspected and certified to be free of M. enterolobii and soil before they leave the state. Sweet potato slips will also be required to have no soil or roots on them before they can leave the state. Sweet potato roots for the fresh market are not regulated under this quarantine. For specific questions regarding how the inspection and certification process will be implemented, please contact your NCDA Plant Protection Specialists. It is important that you make plans for this process with enough time since M. enterolobii cannot be identified visually, which means that sweet potato seed root samples with general root knot nematode damage will need to be sent to the NCDA Nematode Lab for specific identification of M. enterolobii. Because multiple producers may be seeking certification of a shipment at one time and the molecular testing required to do this is time consuming, this may delay the process. Samples found to be positive for M. enterolobii will not be allowed to leave the state. Sweet potato slips only need to be free of soil and roots and may not need the more specialized molecular testing to undergo certification.

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