We conduct applied research under the broad headings of Invasive Species Suppression, and Restoration. These entries are abstracts and posters from scientific meetings such as the Northeastern Weed Science Society.

Suppression of Japanese knotweed with glyphosate or triclopyr following cutting or applied sequentially

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We compared treating twice or cutting followed by treatment using glyphosate or triclopyr for suppression of Japanese knotweed (Fallopia japonica) compared to cutting twice and a control. Herbicide treatments provided significant suppression, and there was no difference between herbicides. This was unusual, as glyphosate is typically more effective than triclopyr.

Suppression of mile-a-minute and Japanese stiltgrass, and non-target impacts with PRE applications of pendimethalin, imazapic, or sulfometuron

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We applied pendimethalin, imazapic, or sulfometuron as preemergent treatments to suppress mile-a-minute and stiltgrass, to plots with or without surface residue, and at a low or high carrier volume. There was no effect due to residue or carrier volume. Pendimethalin provided the best combination of weed suppression and safety to desired residual vegetation.

Glyphosate and triclopyr combinations suppress both autumn olive and Morrow's honeysuckle

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Glyphosate and triclopyr combinations were applied at 3.0 lb total herbicide per acre on an acid equivalent basis, alone or in combination to autumn olive (Elaeagnus umbellata) and Morrow's honeysuckle (Lonicera morrowii). Glyphosate alone controls honeysuckle, but not olive. Triclopyr alone controls olive, but not honeysuckle. A 1:1 mix of both herbicides provided effective control of both species.

Suppression of Japanese stiltgrass and arthraxon and non-target response using PRE herbicides

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A wet meadow infested with arthraxon (Arthraxon hispidus) and Japanese stiltgrass (Microstegium vimineum) was treated PRE with pendimethalin (standard) and new aquatic-labeled herbicides (flumioxazin and bispyribac). Flumioxazin was as effective as pendimethalin, and provides hope of having an aquatic-labeled product for PRE applications to problem annual weeds.

Japanese knotweed response to glyphosate or triclopyr treatment sequences

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A repeat of the 2008 trial, Japanese knotweed (Fallopia japonica) was treated with glyphosate or triclopyr, either following a June cutting or by two variants of a sequential treatment (spring-fall or summer-fall), and compared to cutting twice or no treatment. Cutting was not effective, glyphosate was effective and better than triclopyr, and treatment sequence was not a significant effect.

Carryover effects of aminopyralid, clopyralid, or aminocyclopyrachlor on spring-planted tree seedlings

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Glyphosate alone (G) or in combination with aminopyralid (G+A), clopyralid (G+C), or aminocyclopyrachlor plus chlorsulfuron (G+A+C) was appled in October prior to a spring planting of bare-root silver maple, river birch, flowering dogwood, black walnut, sycamore, or black locust. There was no herbicide by species interaction. Averaged over species, mortality was G - 0%, G+A+C - 6%, G+A - 17%, and G+C - 33%.

The effect of timing and the method of control on Japanese stiltgrass seed production

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Anecdotal accounts suggest Japanese stiltgrass (Microstegium vimineum) can have a subsequent germination flush after removal early in the growing season. Hand pulling, string trimming, or glyphosate application conducted at three timings beginning in early July did not result in any subsequent germination.

Comparison of herbicides for early season suppression of mile-a-minute and impact on non-target vegetation

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Dinitroanaline herbicides such as pendimethalin, prodiamine, or oryzalin are effective PRE treatments against mile-a-minute (Persicaria perfoliata) or Japanese stiltgrass (Microstegium vimineum). Imazapic was added at a low rate (=1 oz/ac 'Plateau') and demonstrated that application could be delayed until germination while maintaining efficacy and safety to non-target vegetation.

Comparison of herbicide mixtures for exotic shrub suppression in wildland settings

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Glyphosate-free herbicide combinations were compared to the standard glyphosate plus triclopyr against burning bush (Euonymus alata), privet (Ligustrum obtusifolium), Morrow's honeysuckle (Lonicera morrowii), autumn olive (Elaeagnus umbellata), and Japanese barberry (Berberis thunbergii). Combinations of triclopyr and aminopyralid plus metsulfuron or aminocyclopyrachlor plus metsulfuron provided control equal to the standard treatment for all species.

Plant species matters in the distribution of Lepidoptera larvae in migratory songbird habitat

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Caterpillars were collected from native (hawthorn, arrow-wood viburnum, silky dogwood, grey dogwood) and exotic (autumn olive, Morrow's honeysuckle) shrub species at Bald Eagle and Yellow Creek State Parks. Caterpillar counts were significantly higher on native species, supporting the hypothesis that native plant species provide greater habitat value.

Can we enhance suppression of reed canarygrass by glyphosate-based treatments in revegetation settings?

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Reed canarygrass (Phalaris arundinacea) in a mixed stand with goldenrods (Solidago spp.) was treated with glyphosate alone or with triclopyr, imazapic or sulfometuron. Adding imazapic did not result in response difference by canarygrass or goldenrod. Adding triclopyr increased goldenrod suppression, but reduced canarygrass suppression. Adding sulfometuron resulted in substantial reduction of both species.

The biocontrol agent Ailanthus Wilt can be transferred to uninfected tree-of-heaven using raw inoculum

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Raw inoculum transfers of Ailanthus Wilt (Verticillium non-alfalfae) using infected plant material resulted in symptoms similar to treatment with enhanced inoculum on tree-of-heaven (Ailanthus altissima).

Further investigations into herbicide selection and application timing to suppress Japanese stiltgrass

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This experiment confirmed that the annual Japanese stiltgrass (Microstegium vimineum) is effectively suppressed with the broadleaf herbicides aminocyclopyrachlor or aminopyralid, while maintaining selectivity to other grasses. Additionally, low rates of glyphosate were effective, and there was no difference in control between early June and July treatments.