Issue link: http://read.uberflip.com/i/1195707
74 POTATO GROWER | JANUARY 2020 Dealing with slugs in commercial potato storage facilities Unlikely Visitor Diggin' In Diggin' In Many insect pests affect potatoes in the field and in storage. In the field, the green peach aphid, potato aphid, beet leafhopper, potato tuberworm, Colorado potato beetle and potato psyllid are among the primary pests in the Pacific Northwest. However, in storage, few insect pests are reported even though some have most likely been inadvertently moved into the storage units from the field. In early fall 2017, samples of rotten tubers with slimy crawling creatures were brought to the Oregon State University Irrigated Agricultural Rondon Entomology Program (IAEP) in Hermiston, Ore. R.J. Mc Donnell, an OSU malacologist based in Corvallis, Ore., identified the creatures as gray field slugs, Deroceras reticulatum. This appears to be the first report in the U.S. of gray field slug infesting potatoes in storage, although there is another report in the literature coming from the Netherlands. This slug species is native to western Europe and is one of the most damaging slugs in the. They are polyphagous, meaning that they can feed in many crops, including wheat, corn, strawberries, ornamentals and several vegetable crops. The presence of this slug in Oregon seems to be an isolated case, since they prefer moist conditions, feeding at night or early morning and moving relatively fast, leaving a slime route behind. When researchers were alerted to the presence of slugs in a commercial storage facility, they literally climbed the almost- four-story-high facility, and encountered slugs on walls and moving on top of tubers. Tubers were collected at random and placed in five-gallon buckets and brought back to the IAEP laboratories, where they were immediately inspected for the presence of slime, slugs per tuber (inside or outside), and feeding damage. In addition, four groups of 50 tubers were placed in buckets and stored in the refrigerator at 8 degrees Celsius (about 46 degrees Fahrenheit) to evaluate the effect of cold temperatures on the biology of this slug species. The slugs' preference for rotten versus healthy tubers was also examined. In general, low temperature seemed to slow them down but did not preclude them from moving, since almost all tubers presented slime. They did not appear to have a strong preference between a healthy or rotten potato, but they could considerably damage healthy STORAGE | By Silvia I. Rondon & Rory J. McDonnell The gray field slug was discovered in 2017 in a potato storage in Oregon. So far, this appears to be an isolated occurrence.