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Managing Potato Psyllids with Insecticides

Tuesday Jun 16, 2026

Potato psyllid adult, nymphs, and eggs (photo by Andy Jensen, NW Potato Consortium).

Potato psyllids are important pests because they can spread the bacterium that causes zebra chip disease. They cannot be stopped from migrating into potato fields. However, they can be controlled once they land. Several strategies for managing potato psyllids with insecticides are described below. In general, more aggressive management of potato psyllids is recommended in years when regional populations are very large, as they pose a greater risk of spreading the disease. Risk tolerance and past experiences with zebra chip are also considerations.

The photo shows a potato psyllid adult and several nymphs (photo by Andy Jensen, NW Potato Consortium).

1) "NO GAPS" PROGRAM WITH EARLY SYSTEMIC INSECTICIDES: Risk-averse growers may choose to use a "no gaps" strategy to control potato psyllids starting with a systemic neonicotinoid insecticide applied at planting or hilling. This can provide about 60-90 days of residual control. The residual control period will vary depending on the rate and amount of canopy growth, application timing, and the specific insecticide and application rate. Then, growers can shift to a foliar insecticide program (see below). Early systemic neonicotinoids also control other pests, such as Colorado potato beetles, beet leafhoppers, and aphids, which can appear in potato fields early in the season.

2) "NO GAPS" FOLIAR INSECTICIDE PROGRAM: If an early systemic insecticide product was NOT used at planting, then risk-averse growers can start a foliar insecticide program when potato psyllids are first detected entering the field or are known to be migrating into the area. The first appearance of psyllids in the Columbia Basin typically occurs from late May to early July, or even later. Earlier appearance usually leads to larger regional populations of psyllids and a higher risk of zebra chip disease. With a no-gaps program, follow-up applications are made to ensure the plants are protected as long as psyllids are present, up to two weeks before vine kill. It is best to choose insecticides that have long residual activity to limit the total number of applications needed. 

Adult potato psyllids moving in and out of potato fields are monitored using yellow sticky cards (photos by Carrie Wohleb, WSU).

The above "no gaps" programs work by preventing the establishment of a population. Adult psyllids are targeted as they enter the field, so they won't lay eggs that hatch into nymphs that become the next generation of adults. These programs may be viewed as overly cautious, considering the minor and spotty incidence of zebra chip in the Columbia Basin most years. However, this aggressive approach may be warranted in years with very large psyllid populations that pose a greater risk of spreading zebra chip.

3) RESCUE TREATMENTS, GENERALLY TARGETING IMMATURE LIFE STAGES: If adult psyllids are not controlled as they enter the field, and eggs and nymphs are present, an insecticide can be applied to control psyllids before they become the next generation of adults. This is a "rescue treatment" for an existing infestation. The aim is to prevent colony establishment and exponential population growth. Insecticides that specifically target the egg and nymph stages are generally used in this case, but it may be preferable to apply a product that controls all life stages since there is often some overlap in psyllid generations. In sentinel plots, we have observed a significant knockback of the psyllid population from a well-timed insecticide application targeting nymphs. This is a riskier approach to managing zebra chip, as infected adults that entered the field earlier could have infected some plants before controls were implemented. But this approach can greatly limit further spread. 

The Potato Decision Aid System features a phenology model that enables growers to track potato psyllid development, including the presence of eggs and the emergence of next-generation adults. This can help growers time "rescue" treatments that target immature stages (when most of the eggs have been deposited and the next generation of adults is just beginning to emerge).  Growers can also collect and examine leaf samples (see below).  

monitoring for psyllid eggs and nymphs
Potato psyllid eggs and nymphs are monitored by collecting and examining leaves. Collect leaves from 10 plants at 10 locations at the edge of the field (intensive sampling is recommended because infestations tend to be spotty). Examine the underside of fully expanded leaves from the top-middle of the plant. Using a magnifying lens is helpful. Potato psyllid nymphs are small, flat, and oval. Eggs are at the end of a short stalk and are orange and football-shaped.

4) RESCUE TREATMENTS TARGETING LATE-SEASON MIGRATING ADULTS: At the end of the season, potato psyllids from vine-killed and harvested fields often make their way into green potato fields. This is particularly concerning during seasons with large psyllid populations, because very large numbers of psyllids can be displaced all at once. Growers who decided to forego a "no-gaps" program, including those who employed "rescue" treatments to control immature psyllids, might consider a "rescue" treatment aimed at incoming adults near the end of the season. It may be prudent in years with large regional psyllid populations, because they pose a greater risk of zebra chip.

For more information on selecting and applying insecticides to control psyllids, refer to the Potato Crop Protection Guide.