Breakout Session: Management with Herbicides

Certification for Application of Herbicides in NY

· Depends on purpose of application (David Quentin)

i.e. Eradication in Wetlands requires: Category 5B license 12 category specific hours with an exam. Apprenticeship 8 hours with certified applicator.

· Possibility of AmeriCorps Labor.

Labeling

· Supplemental labels sometimes contain appropriate uses of herbs not listed on manufacturers label. Need to be sure usages are state approved (Jonathan Soll). Injection in Oregon ran into problems because it was a supplemental label usage.

· Toxicity Reports- Freedom of Information Issue. Difficult to obtain toxicity reports from EPA without the name of a particular file (John Munro).

· Tryclopere, Glyphosphate and Amazopere all have aquatic usages approved by the EPA (Art Gover).

· Actual usage on Knotweed even in riparian corridors is considered a terrestrial usage.

Herbicides

· Glyphosphate– degrades to non-harmful by-products; Non-selective, i.e. kills anything. Seemingly the most effective against knotweed without sacrificing safety.

· Tryclopere– short half-life; specific for broad-leaved plants, will not target grasses and sedges.

Seemingly not as effective as Glyphosate (others claimed equal potency) but perhaps

a better choice, when an area is being recolonized by grasses and sedges, as a secondary

Application.

· Tryclopere with Amine is the aquatic approved formulation and is three times as expensive as Glyphosate. For foliar application the limit is one gallon per acre (Art Gover).

· Amazopere– problems with soil retention; spray crews hired to spray and not eradicate, not invested in success of project. Possibility of contracting with sprayers for necessary amount of reduction.

Application Technique

· Cut back Knotweed and apply herbicide when plants re-grow to 3-4 feet.

· Balance between limiting amount of spray and keeping plants big enough (with enough foliage) to effectively circulate the herbicide to their rhizomes (necessary to get herbicide into rhizome).

· Sexual reproduction aside, better to spray after flower.

· Tradeoff between effectiveness and seed production.

· Better to treat later in the season because after an early treatment, plants will have a chance to grow new sprouts

Injection vs. Foliar Spray

· Injection requires a lot more herbicide than foliar spray; Easy to top acreage maximum with injection alone. Perhaps better to use injection method for small stands and when directly next to the stream to limit accidents.

Management Decisions

· Cost of eradicating large stands is high not only because of size but also concurrent plantings are necessary.

· Impacts of removing that much vegetation are unknown.

· Impacts of extensive chemical use are unknown.

· Perhaps better to focus on areas of high bank scour and leave large stands that are difficult to impossible to control.

· Necessary to be prepared for a short costly control phase and a lengthy and less costly maintenance phase.