In June 2012, PPQ determined that soil samples from two additional fields in eastern Idaho were positive for pale cyst nematodes (PCN). The two fields, located in Bingham County, total 151 acres and are in close proximity to previously identified infested fields. All 17 confirmed infested fields, 1,916 acres total, are within a five-mile radius spanning part of southern Bonneville and northern Bingham Counties. PPQ will publish the addition of these two fields and a list of exposed fields to the regulated area in the upcoming weeks.
PPQ treated the six infested fields detected in 2011-2012 with methyl bromide in May 2012. The five fields currently in bioassay and the four fields with an average viability of less than one percent were not fumigated this year. Operators of the infested fields planted non-host crops in 2012.
Equipment moving from non-infested APHIS-regulated fields may require cleaning prior to their movement out of the field. Cleaning can be performed by either APHIS personnel or by private parties. New in 2012, stakeholders have the option to conduct their own inspections and self-certify their cleaned equipment by entering into a compliance agreement with APHIS. The compliance agreement requires stakeholders to attend a sanitation training course offered by the PCN Program and to document and retain for review information about equipment sanitation and movement. For more information about self-certification or to sign up for sanitation training, please contact the program office at (208) 522-2431.
Research and plans for field trials are currently underway to provide additional non-fumigant treatment options for infested fields. These include fungal bio-control agents that attack PCN cysts, and trap crops and hatching factors that stimulate PCN eggs to hatch but do not provide a food source, which is essential for completing the nematode's reproductive cycle. Rapeseed meal, a byproduct of canola oil production, is being evaluated for use as a bio-fumigant against PCN. The meal is amended into the soil and releases glucosinolates that can kill PCN larvae. Since the rapeseed meal is processed, there is little odor released into the atmosphere unlike the arugula green manures utilized previously by the program.
In February 2012, PPQ found that two additional infested fields in the eradication program had no viable nematodes according to a non-vital staining analysis conducted at the PCN laboratory in Idaho Falls. Three fields already reached zero viability in 2010. Cysts collected from these five fields advanced to bioassay, which is the next step toward determining eradication success.
Bioassay assesses nematodes' ability to hatch from a cyst, infect a host plant and reproduce. Bioassays are currently underway in a greenhouse at the University of Idaho in Moscow, Idaho. The entire bioassay process takes 1.5 to 2 years to complete. The bioassays that started in 2011 are ongoing; preliminary results obtained in early 2012 have been favorable.