PCN Find Continues To Stump Idaho, USDA

Published online: Jun 01, 2006
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A 21-person team is continuing its work in efforts to trace the source of a potato cyst nematode found in eastern Idaho in April.

So far, over 5,500 soil samples have been taken and checked for the nematode but all with negative findings.

Only the initial sample taken from tare soil at an Idaho potato grading station has produced a PCN. Idaho State Department of Agriculture and APHIS scientists are continuing to gather information on used farm equipment imported from countries where PCN is known to occur.

This investigation is based on the possibility that PCN may have been transported onboard foreign farm equiment, according to a May 31 news release from the ISDA. There is still no conclusive evidence that PCN originated from an eastern Idaho potato field.

However, because of the possibility that PCN did originate with a field, the scientists will continue to explore leads for sources of such an infestation.

In the meantime, soil samples are still being collected from piler soil and at storages which provided potatoes to the grader station on the same day as the positive sample was found. If piler soil is not available, then fields that grew potatoes will be sampled.

The release noted that 28 different farm operations sent potatoes to the grader station on that day in February when the original positive soil sample was collected.

The ISDA says growers are being very cooperative in assisting with tracking down the source of the nematodes. This is important, the ISDA says, because any possible source needs to be found as quickly as possible to avoid the possible spread of the nematode into production areas.

APHIS emergency action notifications and ISDA restrictions have been imposed at suspect sites. These actions restrict the movement of soil, plants, plant material and farm equipment wnhich may have been exposed to the potato cyst nematode. They are intended to prevent the introduction and dissemination of the pest, according to the ISDA.

To date these restrictions have been imposed in Bingham, Bonneville and Jefferson counties. However, they are currently limited to only five sites--two fields, one packing plant and two storage units. The fields are not being planted to potatoes this year. No soil is to be moved from the fields, and equipment leaving the fields must be cleaned of soil. Soil in the settling basin at the packing plant must be moved to an approved disposal site. Except for equipment which must be cleaned, nothing is to enter or leave the storages until they ae released from the regulation.
APHIS has deregulated the tare soil at two potato processing plants. The action came after the facilities were determined to be free of PCN. Under APHIS/ISDA supervision, facililty pesonnel were able to dispose of all the tare soil that may have been associated with the potatoes that went through the grading station on the same day as the samples in which the PCN was discovered.