Tolerance of Old World Climbing Fern (Lygodium microphyllum) Spores to Herbicides

Abstract

Old World climbing fern (OWCF) is a highly invasive fern that disrupts natural communities in central and southern Florida. OCWF produces copious, wind-blown spores that have propelled its rapid invasion of Florida's natural areas over the last few decades. Current management of OWCF is limited to herbicides and natural resource managers in Florida have questioned if herbicides inhibit spore germination. This study compared spore germination rates of OWCF exposed to six herbicides and a surfactant from 1 to 24 h under laboratory conditions. Spores of OWCF were highly susceptible to metsulfuron, but exhibited tolerance to imazapyr, glyphosate, fluroxypyr, asulam, and triclopyr. Spore germination rates were 0.4% for spores exposed to 0.1 g ai L−1 of metsulfuron, but 0% for rates greater than or equal to 0.2 g ai L−1 at 30 d after treatment (DAT). Reduction in spore germination was observed with all other concentrations of herbicides tested, ranging from 10.4% with triclopyr (40 g ai L−1) to 42.6% with asulam (4.2 g ai L−1) compared to 47.9% germination for untreated checks 30 DAT. Spores were highly sensitive to metsulfuron with herbicide concentrations required for 50 and 95% inhibition of spore germination (I50 and I95) measuring 0.014 and 0.063 g ai L−1, respectively; spores were greater than 1,000-fold more sensitive to metsulfuron compared to I95 concentrations of any other herbicide tested. These results indicate that metsulfuron exhibits potential to control OWCF spore germination but spores are tolerant to the five other herbicides tested.

Evaluation of novel triclopyr formulations for control of Old World climbing fern (Lygodium microphyllum)

“…Eight treatments were applied, including three triclopyr formulations (triclopyr acid, Trycera™ herbicide, 344 g L −1 , Helena Agri-Enterprises, Collierville, TN, USA; triclopyr amine, Garlon ® 3A, 360 g L −1 , Corteva Agriscience, Indianapolis, IN, USA; triclopyr choline, Vastlan™ herbicide, 480 g L −1 , Corteva Agriscience) at two concentrations each (5.4 and 10.8 g L −1 ); glyphosate (Roundup ® Custom, 480 g L −1 , Bayer CropScience, Monheim am Rhein, Germany) at the commercial standard concentration of 14.4 g L −1 (which is equivalent to 3% v/v; Hutchinson et al 2006); and a nontreated reference. Triclopyr concentrations were chosen based upon previous research that indicated triclopyr amine applied at 7.2 g ae L −1 resulted in >90% control at 6 MAT (Hutchinson and Langeland 2007). Each treatment was replicated four times.…”

“…Greenhouse and field trials examining the effectiveness of triclopyr amine resulted in 100% necrosis for 10 wk posttreatment (Hutchinson and Langeland 2007). Triclopyr amine treatments, even at high rates of 6.7 kg ae ha −1 (6 lb ae acre −1 ) resulted in excellent control of L. microphyllum with a concomitant increase in native vegetation and species richness (Hutchinson and Langeland 2007). In addition, triclopyr is absorbed more thoroughly by L. microphyllum at 60% when compared with the standard treatment of glyphosate at 31%, although most of the chemical remains in the leaves, showing minimal basipetal translocation regardless of the treatment (Hutchinson et al 2010).…”

Limited Field Establishment of a Weed Biocontrol Agent, Floracarus perrepae (Acariformes: Eriophyidae), Against Old World Climbing Fern in Florida - A Possible Role of Mite Resistant Plant Genotypes

“…Lygodium microphyllum is difficult to manage using controlled burns, mechanical removal, or herbicide applications due to the plant's ability to regenerate from underground rhizomes (Stocker et al 1997;Goolsby et al 2003, Hutchinson et al 2006. Despite satisfactory kill of aerial vines from herbicides, 3-5% of the L. microphyllum individuals regrow and require repeated treatments to achieve mortality of the perennial underground rhizomes Lockhart 2007;Boughton & Pemberton 2008).…”

Biology and Reproductive Parameters of the Brown Lygodium Moth, <I>Neomusotima conspurcatalis</I> - A New Biological Control Agent of Old World Climbing Fern in Florida

“…The rapid spread of L. microphyllum, its impact on native communities, and the lack of effective long-term control using conventional management techniques prompted the start of a classical biological control program in 1997 (Goolsby et al 2003;Hutchinson et al 2006). The ongoing search for potential biological control agents has focused on Asia and Australia (Pemberton 1998;Goolsby et al 2003).…”