Turnaround Times for N.C. Nematode Testing Expected to be Long

Jim Rogers Pests

RALEIGH – The North Carolina (N.C.) Department of Agriculture and Consumer Services’ (NCDA&CS) Nematode Assay Lab is warning growers to expect turnaround times of 15 weeks or longer for routine (predictive) nematode samples submitted this year.

North Carolina nematode testing
Healthy carrots show no nematode damage (left) compared to carrots infected with root-knot nematodes (right). Note the circled galls on both hairy and tap roots.

Samples submitted for diagnostic testing, including molecular diagnosis of guava root-knot nematode species, will be given priority. Those results should be available in around five working days. Currently, there are around 15,400 samples waiting analysis.

The Nematode Assay Lab can assay soil samples for the presence of at least 46 different plant-parasitic nematodes, which are microscopic threadlike worms that live in the soil. The results of a nematode assay help growers make important management control decisions for the upcoming crop season.

North Carolina nematode testing
Figure 2. Swollen and galled roots caused by root-knot nematodes on tomato (left) and hemp (right).

Increased demand for testing and staffing shortages have led to the long turnaround times, said Weimin Ye, NCDA&CS nematologist.

“This is highly detailed work, requiring up to a year of specialized training for nematology technicians,” Ye said. “Even with three experienced nematology technicians and a lab manager qualified to identify and count nematodes, only about 200 samples can be completed daily.”

Two new staff members are currently in training and five temporary employees have been hired to help extract nematodes from samples in preparation for analysis by trained staff.  

“We are estimating that samples received before Dec.1 should be completed by the end of March 2023. Samples are being processed in the order that they are received,” Ye said. “Given the anticipated delays, growers should consider whether or not assay results will be ready in time to make management control decisions before submitting additional samples to the Nematode Assay Lab.”

Long storage times in the lab are not expected to impact assay results, as the nematodes are at the overwinter stage and do not feed and reproduce, Ye said.

Producers can check estimated turnaround times at https://www.ncagr.gov/agronomi/PALS/Default.aspx. Growers with nematode-specific concerns or questions can contact Ye at 919-664-1600 or by email at weimin.ye@ncagr.gov.