Potato Tuber-worm "A New Threat to Potatoes"

This past summer UI entomology specialists searched for signs of a new potato pest, the Potato Tuber-worm. In their search they found two adult Tuber-worm moths, but found no evidence of tuber or plant damage caused by feeding. The specialists feel that since they only found two adults, this pest is not yet established in Idaho. The tow adults could have been trucked in from outlying states. It is felt however that the moth could survive in Idaho and has the potential to become established. For this reason all potato growers need to be on the lookout for this moth or its larval form in their fields. Bring any suspect insect into the office for identification. The adult moth has characteristic hairs at the terminal abdominal segments.

The insect's larva feed on tubers, excavating tunnels and leaving telltale frass at the tunnels entrance. These tunnels then allow bacteria and fungi to enter and destroy the tuber. The larva also damages potatoes with their leaf mining (feeding).

Some of the most damaging feeding of this insect occurs in storage. Eliminating the damaged tubers and treating the remaining tubers going into storage is critical. "Bt" has been the chemical that has shown best control of tuber-worm. Not planting infested tubers, moving potato fields to new areas, and destroying any volunteer potatoes are other control measures that should be followed.

Do you have a bug and you're not sure what it is? Bring it to our Extension Office and we will be happy to help. We also provide assistance in plant and weed identification, soil analysis, pest problems, such as gophers, voles, any infestation you may have. We have a Horticulture Assistant on staff to help you out. Please call 208-236-7310 or stop by at 130 N. 6th, Ste. B, Pocatello, ID 83201. 

We look forward to another year working with the people of Bannock County and hope to hear from you soon.