Potato Cyst Nematodes

Background

Potato cyst nematodes (PCN), 

Globodera pallida (pale cyst 

nematode) and G. rostochiensis

(golden nematode), have been 

detected in the United States. 

G. pallida was found in Idaho 

in 2006, and G. rostochiensis 

was found in New York in 1941. 

These microscopic nematodes 

mainly affect plants within the 

potato family, including highvalue crops such as potatoes, 

tomatoes, and eggplants. They 

also affect some weeds. 

PCN are a major threat for 

agricultural industries. If these 

pests were to spread unchecked 

in the United States, it could 

stop commerce in potatoes and 

nursery stock and seriously harm 

U.S. agricultural production, the 

environment, and our economy. 

Pest Alert Animal and Plant Health Inspection Service

Plant Protection and Quarantine

Description

PCN are soil-borne organisms. 

The pests do not infest potato 

tubers; rather, they infest feeder 

roots, where the females attach, 

feed, and become sedentary. 

Nematodes reproduce sexually. 

Males are attracted to females by 

a pheromone (sex attractant) and 

may mate several times. Females 

form cysts containing 200 to 600 

eggs. Cysts can stay dormant 

for up to 30 years while the eggs 

inside remain viable. 

Large numbers of nematodes 

cause wilting, stunted growth, 

poor root development, and early 

plant death. If left uncontrolled, 

PCN can reduce yields up to 

80 percent in potato fields. 

Even with only minor symptoms 

showing on leaves, PCN can 

significantly reduce tuber size.

The main way PCN spread is 

when cysts are moved from one 

place to another in soil. This may 

occur with the movement of soil 

on farming, construction, and 

other equipment; infested soil 

adhering to seed potatoes and 

other host crops; and related 

items or means of transport that 

pose a risk for spreading PCN.

Detection

Every year, the U.S. Department 

of Agriculture’s (USDA) Animal 

and Plant Health Inspection 

Service (APHIS) works 

cooperatively with States to 

conduct a voluntary national 

survey for PCN. The purpose 

is to determine the pests’ 

distribution and extent of 

infestation in the United States. 

A healthy potato plant (left), compared to one infested with the 

potato cyst nematode (Christopher Hogger)

Features of the potato cyst nematode (Jonathan D. Eisenback, 

Virginia Polytechnic Institute and State University)
Since the first findings of pale 

cyst nematode in Idaho in 2006 

and golden nematode in New 

York in 1941, APHIS and State 

officials have examined hundreds 

of thousands of soil samples 

from surrounding production 

fields, seed potato fields, 

nursery stock, and storage and 

packaging facilities. To date, we 

have isolated the nematodes to a 

small geographic area spanning 

two counties in southeastern 

Idaho and eight counties in 

New York. 

No soil samples collected 

through the survey have 

contained either species of PCN.

Control Measures

USDA-APHIS cooperates with 

Idaho and New York to carry 

out PCN programs in place 

in each of these States. The 

Female nematodes on potato root (Bonsak Hammeraas, Norwegian 

Institute for Agricultural and Environmental Research)

Potato cyst nematodes extracted from soil (Christopher Hogger, 

Swiss Federal Research Station for Agroecology and Agriculture)

USDA is an equal opportunity provider 

and employer.

Photo Credits: All four 

images were taken from 

www.forestryimages.org and are 

reproduced by permission. Individual 

photographers are credited in the 

captions.

APHIS 81-35-010

Revised May 2015

programs aim to prevent the 

pests’ spread to uninfested 

fields. Each program defines 

separate restrictions for pale cyst 

nematode (G. pallida) and golden 

nematode (G. rostochiensis). The 

restrictions cover the movement 

of plants and soil, with required 

sanitation procedures for 

equipment. Commercial potato, 

seed potato, and nursery stock 

producers in Idaho’s and New 

York’s regulated areas who 

ship their products intrastate, 

interstate, or internationally must 

follow these requirements.

For More Information

To learn more about PCN and 

related restrictions, visit the 

APHIS Web site at www.aphis.

usda.gov/planthealth/pcn.