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. Some different strategies for managing potato psyllids using insecticides are described below.

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 of canopy growth, application timing, and the specific insecticide and application rate used. 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 during the early part of 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. 

The above 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.

3) RESCUE TREATMENTS TARGETING IMMATURE 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. 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. This is a riskier approach to potato psyllid and zebra chip management, as infected adults that enter the field could bring the disease in. But this approach can 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. Growers should also collect and examine leaf samples (see below).  

4) RESCUE TREATMENTS TARGETING LATE-SEASON MIGRATING ADULTS: At the end of the season, potato psyllids from harvested fields often make their way into green potato fields. This is particularly concerning during seasons with large populations of psyllids since zebra chip incidence is highest in those years. Growers who decided to forego a "no-gaps" program, including those who employed "rescue" treatments to control immature psyllids, should consider a "rescue" treatment aimed at incoming adults at the end of the season. It may be prudent in years with large regional populations of psyllids.

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