The potato psyllid is the vector for the bacterium that causes zebra chip and tests are currently being performed at NDSU to determine if the psyllids found in North Dakota carry the bacterium. It is likely that these psyllids do not carry the zebra chip bacterium since most tests conducted on psyllids collected in Texas, Kansas and Nebraska have been negative.
However, it is important for potato growers to be cognizant that psyllids can cause yield and quality damage to potato in the absence of zebra chip due to a toxin they inject into the plant during feeding. This toxin causes a disrupts the flow of carbohydrates from the leaves to the roots and tubers reducing the bulking rate of the tubers. This condition is known as “psyllid yellows”.
Symptoms of psyllid yellows are extreme cupping and erectness of the upper leaves which will redden and become yellow as the toxin intensifies. At this point, all tuber bulking ceases and is irreversible. It is important for growers to scout fields for psyllids by sweeping foliage to look for adults and to examine the underside of leaves for nymphs in the middle to upper third of the canopy.
Potato Psyllid photos on Google
Psyllids are very difficult to see with the naked eye so a hand lens is recommended for detection. Several insecticides are available for the control of psyllids in potato. Agrimek/Epimek has excellent activity on psyllid adults but has a short residual. Fulfill and Beleaf are active on first and second instar nymphs. Oberon is active on first to fourth star nymphs.
Note: the NDSU Blightline is sponsored by Syngenta Crop Protection.
