May 3, 2012

Potato/tomato psyllids have begun to arrive in Nebraska. A transect of 100 psyllid traps have been monitored over the past couple weeks and this week's sample revealed at least one potato/tomato psyllid. This indicates that these insects are on the move and likely settling on alternate hosts such as field bindweed and ground cherry.

Potato planting is well underway in Nebraska and growers should be scouting their fields for these psyllids as we're likely to see an early infestation this year. It will be important to remember that scouting and timely insecticide application can be critical to effective control.

The potato/tomato psyllid also is thought to be a vector for the zebra chip disease, a relatively new and potentially devastating disease for Nebraska potato producers. Plants with this disease display a wide range of symptoms, including ones resembling psyllid yellows, swollen nodes resulting in a zigzag orientation of stems, proliferation of axiliary buds and aerial tubers, and leaf scorching.

Scouting

To scout for potato psyllid nymphs (i.e., the stage associated with psyllid yellows) in potatoes, randomly select five groups of 10 lower leaflets throughout the field (50 leaflets total). Consider treating the field if there is more than one nymph per 10 leaflets on pre-flowering plants, or three to four nymphs per 10 leaflets on plants in full flowering or older.

For managing the psyllid for zebra chip disease the current early-seaon threshold is set at one psyilld per field. However, fresh-market producers or seed-potato producers should not need to manage for zebra chip. Seed treatments or in-furrow applications may be the best option for managing for early-season psyllids when managing for zebra chip disease.

It is important to take samples representative of the entire field. Be aware of features in the landscape that may facilitate the adults settling from the air. For example, a tree line can create eddies that could concentrate psyllid numbers in fields downwind. Psyllids may invade fields from borders with weeds such as ground cherry or nightshade.

More Information

For more information on this insect, the diseases associated with it and how to manage it please see NebGuides, The Potato/Tomato Psyllid (G2113) and Zebra Chip Disease of Potatoes in Nebraska (G2112).

Jeff Bradshaw, Extension Entomologist
Bob Harveson, Extension Plant Pathologist
Both at the Panhandle REC, Scottsbluff