Hi all
I don't know if you have been following the debate on the biocontrol of knotweed, but the comments keep rolling in. Near as I can tell, the comment period actually ended in July. I have perused most of the comments, and the following was posted early on. I thought it was a balanced presentation, so I quote it in full:

Comment from Joel Price

The Oregon Department of Agriculture, in collaboration with The Research Group, LLC., prepared a study entitled "Economic Impact from Selected Noxious Weeds in Oregon, 2014". Japanese knotweed was one of the species specifically profiled. They found in 2012, the number of acres infested statewide was 42,000. More importantly, the number of acres susceptible to invasion based on the model (precipitation, elevation, growing degree days, ect.) was nearly 1.8 million acres in Oregon. This translates to $1.3 million dollars of negative economic impact to the state every year.

As the biocontrol entomologist for the Oregon Department of Agriculture, I have personally surveyed over a dozen knotweed patches across six counties just this spring. I have seen, first-hand, the monotypic stands it forms, blocking access to waterways for boat ramps, fishing, and animal use. I have also conversed with several land-managers who look to biocontrol for holding all the ground they have gained over the last decade with herbicide and mechanical control. Much of this work was done with non-permanent grant funding. Our soil and water conservation groups are counting on knotweed biocontrol. The stands remaining in the most heavily infested counties are well beyond our private, municipal, and county partners abilities to further impact due to spray risks, budget limits, or labor logistics.


In regard to concerns about losing knotweed as a beneficial source for insects, I am an entomologist with a background in ecology. I am concerned with the preservation of all pollinators. However, biocontrol acts slowly, across decades, and rarely if ever eradicates the target weed entirely. The slow rates and moderate levels of control anticipated should give any organism utilizing the patches sufficient time to adjust food sources to the many native plants and nutritive sources of nectar. After a quick search of the Google Scholar archives, I saw no papers establishing knotweed as a critical host plant for honey bees. This makes sense given the plant's relatively short flowering period and overall propensity for vegetative reproduction. Biocontrol use on knotweed has the potential to reduce herbicide and mechanical use that will otherwise continue to pose risks to pollinators.

The potential concerns with bee keepers and noxious weed control are not new. In fact, a study by Nordblom et al. 2002, "Benefit-cost analysis for biological control of Echium spp. (Paterson's curse and related species) in Australia" demonstrated the detrimental effects of this common bee food source outweighed the benefits by 10:1. A post-release analysis in Australia found a Net Present Value of benefits from this one biocontrol is approximately $1.2 billion. Utilizing a similar wholistic paradigm, our state stands to benefit significantly from knotweed biocontrol.

I have read the safety and impact research reports for this agent, witnessed the agent in quarantine, and spoken with experts where it has been released in other countries. In short, I fully support permitting the release of Aphalara itadori for the control of invasive knotweeds in Oregon. Should permitting occur, we intend to immediately utilize this beneficial insect as requested by the overwhelming majority of our land management partners statewide.

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