Sixth World Potato Congress Tackles Potato Tuber Moth

Published online: Aug 21, 2006
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Researchers kicked-off the Sixth World Potato Congress with a symposium  dealing with Integrated Pest Management for the Potato Tuber Moth - a potato pest of global proportions.

PTM originated with the potato in South America and is a pest of other solanaceous crops and weeds. Like the potato, it has made its way around the world and is found in many regions with diverse climates. The pest causes direct field losses, but growers typically first note losses that occur in storage.

Silvia I. Rondon with the Oregon State University - Hermiston Agricultural Research and Extension Center noted that the 2002 discovery of PTM in the Columbia Basin is particularly concerning to growers because of a zero tolerance level of larvae on tubers by U.S. processors. After the 2002 discovery, several fields were rejected inflicting millions of dollars in losses to Columbia Basin Growers.

Since the initial discovery near Hermiston, OR, the range has expanded 140 miles north into Washington. In 2005, traps in three counties in southwest Idaho also showed the pest had moved eastward.

In 2006, traps have yielded less adults. This may be a result of cold winter temperatures along with Columbia Basin growers agressively controlling the pest with insecticides. Despite this, PTM numbers are expected to spike again in the future.

According to U of I Entymologist Dr. Juan Alvarez, the PTM was first found in 1856 in California. It is present in 25 U.S. states including Texas, Florida, Colorado, Virginia, Oregon, Washington and Idaho.

When the pest was found in traps from Idaho's Canyon, Payette and Elmore counties, the Idaho Potato Commission funded an extensive control program. With cooperation from the Idaho State Department of Agriculture, traps increased from around 45 up to 461.

Field scouting focused on PTM and 3,442 pounds of tubers were collected. These were processed with fry cutting equipment to see if larvae had infested them. To date, no infested tubers have been found, and leaf mines from larva have not been found.

Other researchers made presentations discussing efforts from around the world to control PTM. Various programs, tools and products are in continual development.

Programs with seasonal forecasting based on temperature and geographic information systems are in development along with biological control products and cultural practices. Natural parasitoids of PTM are showing some success and will likely play a key role in future IPM practices. These are said to limit the resistance to insecticides and don't require pre-harvest intervals.

PTM will continue to be a challenge to the industry. As Rondon stated, "With the potato tuber moth, there are still more questions than answers." Nevertheless, the new development of tools and information will give the industry the upper hand.