Some invasive plants are listed as “prohibited for sale” on the Florida Department of Agriculture and Consumer Services Noxious Weed List, however many invasive plants are commercially available. Plant This, Not That: A Guide to Avoiding Invasive Plant Species in Florida is a laminated, ring-bound-flipbook written to provide safe alternatives to commonly sold invasive ornamental plants. Perfect for the resident or professionals visiting or running a nursery or garden center, this relevant resource includes 22 invasive plants that are commonly available for sale along with native or Florida-Friendly alternatives. Over 1,350 copies have been sold or distributed, bringing in $14,234. Concepts from the book have been integrated into classes for landscape professionals, industry nursery owners, master gardeners and the general public. Results from the classes show 1.) 367/376 or 97.6% increased their knowledge about the impact invasive species have in Florida, 2.) 371/373 or 99.4% intend to use the information from the class to choose plants that are not invasive, and 3.) 323/344 or 93.9% of participants felt more confident they could identify invasive plant species. Follow up surveys indicated participants used hand pulling to remove invasives (85% or 51/60), avoided invasives from the book (76% or 45/59) and educated others about invasive species (75% or 44/59). Intentional efforts to widely publicize the usefulness of this guidebook and its impact in extension programming have resulted in 11 articles reaching thousands of people, 2 interviews one on NPR and another on the radio, 3 webpages, one press release published on behalf of ASHS, and one journal article in the Journal of Hort Technology.
Tina McIntyre is the Florida-Friendly Landscaping™ Agent at the UF/IFAS Extension in Seminole County. She specializes in surface water quality and quantity, best management practices related to landscape management, and restoration of urban green spaces. Tina came to Extension after... Read More →
Dr. Sandra Wilson is a Professor of Environmental Horticulture at the University of Florida’s main campus in Gainesville. She received B.S. and M.S. degrees from the University of Delaware and a Ph.D. in Plant Physiology from Clemson University. Dr. Wilson completed postdoctoral... Read More →
Friday August 1, 2025 8:00am - 8:15am CDT Strand 10
Horseweed (Conyza canadensis) is a prevalent weed species that has garnered significant attention due to its increasing resistance to multiple herbicides. Glufosinate, a widely utilized herbicide, is among the agents employed for its control. This study investigated the causes and impacts of glufosinate-induced oxidative stress in horseweed. During the flowering stage, glufosinate ammonium (GA) was applied at recommended concentrations. The plants were cultivated in a controlled greenhouse environment maintained at day/night temperatures of 27/25°C, with a 16-hour photoperiod and 75% relative humidity. Morphological symptoms, including curling and burning of leaf tips, were observed within 24 hours of GA application. Elevated levels of hydrogen peroxide (H2O2), malondialdehyde (MDA), and superoxide dismutase (SOD) were detected four hours post-application and persisted for 48 hours. In contrast, activities of catalase (CAT) and ascorbate peroxidase (APOX) were reduced. Notably, guaiacol peroxidase (GPOD) activity increased in GA-treated horseweed leaves. Senescence of leaves and flower inflorescences was evident five days post-application. This study enhances the understanding of glufosinate-induced oxidative stress in horseweed, elucidating the plant's biochemical and molecular responses. The findings contribute valuable insights for improving weed management strategies and promoting agricultural sustainability.
Non-target-site herbicide resistance was evaluated in commercially available herbicides labeled for the management of Palmer Amaranth (Amaranthus palmeri). Seven treatments (T1: Control, T2: Flexstar (22.1%), T3: Buccaneer 5 Extra (53.8%), T4: Flexstar (5.88%) GT3.5 with Glyphosate (22.40%), T5: Defy LV-6 (88.4%): 2,4-D, T6: Enlist Duo (Glyphosate: 22.1% 2,4-D: 24.4%), and T7: Dicamba were applied at recommended rates. Glutathione-S-Transferase (GST) and Glutathione Reductase (GR) activities were measured in leaf samples after 15 minutes of herbicide exposure. Glyphosate exhibited the highest GST activity, followed by Fomesafen > Fomesafen Glyphosate > 2,4-D > Dicamba > 2,4-D Glyphosate. Treatments with a single mode of action exhibited higher GST activity, while mixed-mode treatments showed lower GST levels. Interestingly, an inverse relationship between GST and GR activity was observed, suggesting a compensatory mechanism. When GST activity was low, GR activity increased, indicating that the plant may enhance glutathione regeneration through GR to sustain detoxification capacity and manage oxidative stress. This biochemical compensation could enable the plant to survive herbicide exposure, even when direct detoxification (via GST) is limited. Such adaptability might contribute to the gradual development of non-target-site resistance, as the plant's defense system finds alternative pathways to mitigate herbicidal damage. These findings highlight that herbicide with a single mode of action, which trigger higher GST activity, may accelerate resistance evolution. In contrast, mixed-mode herbicides, which induce lower GST activity and potentially limit compensatory responses, can slow the progression of resistance. Thus, diversified herbicide strategies are essential for sustainable and effective management of Palmer Amaranth.
