APPENDIX E. Exotic Species Control Plans (Including Exotic Pest Plant Council s 1999 List of Florida s Most Invasive Species)

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1 APPENDIX E. Exotic Species Control Plans (Including Exotic Pest Plant Council s 1999 List of Florida s Most Invasive Species) E-1

2 The Florida Exotic pest Council has developed a list of Florida s Most Invasive Species (see back of this Appendix). The purpose of this list is to focus attention on the impacts that these plants have on our native ecosystem s biological diversity and function. Definitions: Exotic a non-indigenous species, or one introduced to this state, either purposefully or accidentally. A naturalized exotic, such as those listed here, has escaped into the wild where it reproduces on its own either sexually or asexually. Native a species already occurring in Florida at the time of European contact (1500). Invasive a variable condition defined by the category to which the species is assigned. Category I Species that are invading and disrupting native plant communities in Florida. This definition does not rely on the economic severity or geographic range of the problem, but on the documented ecological damage caused. Category II Species that have shown a potential to disrupt native plant communities. These species may become ranked as Category I, but have not yet demonstrated disruption of natural Florida communities. To date, site management has tried to locate and immediately eradicate Category I species Control plans for species known to occur on site follow. The herbicides recommended below have shown very low toxicity to wildlife that they have been tested on. Most Pervasive Invasive Exotics at Weedon Island Preserve Brazilian Pepper (Schinus terebinthifolius) A native to tropical America, Brazilian pepper is the most aggressive exotic at Weedon Island. Peppers are found scattered throughout the preserve in every terrestrial biological community. It is least common in the second growth scrubby Flatwoods community and in the maritime hammock community. It forms dense monocultures on mosquito ditch spoil mounds. Brazilian pepper is the most abundant exotic on the island despite the fact that tree size indicates that most specimens have existed in the preserve for less than 30 years. Pepper seeds are dispersed across the area by water and animals. Cut stump treatment with 50% Garlon 3A, 10% Garlon 4 or a basal bark application of 10% Garlon 4. Foliar application of Garlon 4, Garlo 3A, Roundup Pro, Roundup Super Concentrate, or Rodeo, according label directions may be used when appropriate. Glyphosphate products are less effective when used alone in spring and early summer. Use Rodeo or cut stump application of 50% arsenal where plants are growing in aquatic sites. E-2

3 Australian pine Australian pines were probably planted in the airstrip area at Weedon Island when the airport was in operation. Australian pine grows rapidly, forms dense monocultures, tolerates saline conditions and grows in a wide range of soil moisture. The tree needles (actually tiny jointed branches) apparently inhibit plant growth as little vegetation occurs in the under story. Australian pines have a shallow root system. They do not resist erosion well, topple easily in high winds, and the roots can create a barrier to sea turtle nesting when trees grow directly on the beach. The trees are resistant to termites and do not readily decay after being killed by girdling. Australian pines can only withstand mild freezes, and two consecutive severe freezes in the winters of , and have killed many of the trees on Weedon Island. Some of the trees are making a comeback on the mosquito ditches, even after these three freezes. Australian pines are found in scattered clusters throughout the mosquito control mounds in the preserve. Basal bark treatment with 10% Garlon 4 is very effective, as is a cut stump treatment with 50% Garlon 3A or 10% Garlon 4. When basal bark treatment is used on trees greater than 1 in diameter, it may be necessary to slough off loose bark in the application area to prevent the bark from trapping the herbicide. Melaleuca (Melaleuca quinquenervia) In its native range of southeast Asia and Austrailia, melaleuca grows in both uplands and wetlands. Unfortunately, all natural areas in south and central coastal Florida are vulnerable to melaleuca invasion. Introduced to Florida from Australia as an ornamental at the turn of the century. Single specimens also occur on Googe and Ross Islands. Melaleuca grows very rapidly with trees as young as two years old producing seeds. The seeds are not airborne so seed germination is usually in the vicinity of the parent tree. Melaleuca have a thick bark and cannot be controlled by fire. Viable seeds already on the trees cannot be killed with herbicide or by cutting the tree down. Any interference with water flow through the xylem to the seed capsules triggers seed release. For seedlings and saplings: (1) hand pull, being sure not to break plant off of root system and remove or place in piles to help reduce the chance that they will re-root or: (2) treat with Foliar, low volume spot application of 5% Rodeo. E-3

4 Carrotwood (Cupaniopsis anacardioides) A native to Australian carrotwood tree was introduced to the states as a shade tree in the early 1900's. It propagates by seeds and air layering. Its rated as fair for salt tolerance and prefers a ph from 6.0 to 8.0. It grows in well drained enriched soils. The shell mounds are the most vulnerable for invasion by this species. The carrotwood tree will not form dense monocultures and will not withstand a hard freeze (25?F) or below. Carrotwood is best treated basally with bark treatment of 10% Garlon 4 or cut stump treatment with 50% Garlon 3A. Other common exotics at Weedon Island Woman s tongue (Albizia lebbeck) Common in hammocks at Weedon Island. Basal bark treatment with 10% Garlon 4. Cut stump treatments are also effective with 50% Garlon 3A or 10% Garlon 4. Small seedlings can be hand pulled. Castor bean (Ricinus communis) Basal bark or cut stump treatment with 10% Garlon 4. Site must be revisited several times to pull up seedlings. Indian rosewood (Dalbergia sissoo) Invasive along hammock margins, very salt tolerant. Basal bark treatment with 10% Garlon 4. Guava (Psidium guajava) Basal bark application of 10% Garlon 4. Cogongrass (Impereta cylindrica) Tends to spread along roadways and utility lines. 3-4qt. Roundup Pro, 2-3 qt. Arsenal, or 0.5 qt Fusulade per acre. Herbicides should be used in combination with burning or tillage for optimum control (apply herbicides after burn or mow). 1 Key References: 1 See IFAS Publication SS-AGR-52 for additional information. E-4

5 Langeland, K.A., and R.K. Stocker Control on non-native plants in natural areas of Florida. Publication SP242. University of Florida, Institute of Food and Agricultural Sciences, Gainesville. Florida Weed Management Guide. Annually updated reference for chemicals used in weed control in Florida. Publication SP53. University of Florida, Institute of Food and Agricultural Sciences, Gainesville. Aquatic Weed Management Guide. Publication SP55. University of Florida, Institute of Food and Agricultural Sciences, Gainesville. These Publications can be ordered by contacting: Publications Distribution Center University of Florida P.O. Box Gainesville, FL E-5