1. Definitions Control – prevention of spread by removing fruits and limiting vegetative spread Eradicate – to completely remove a species from a location

2. Topics Approaches to control Methods of control –Mechanical –Chemical (types of herbicides, application methods Selected PNW species

3. Assessing Invasive Species Threats At the landscape scale it is necessary to take two approaches simultaneously and iteratively: By spatial distribution of invaders and conservation goals (Superlative sites) By invasive species (Scary species)

4. Two Assessment Approaches Species Based Site Based

5. Acres Infested Eradication simple Plant absent Eradication feasible Eradication unlikely, intense effort required Scattered locations Numerous locations At or near biological potential Local control and management only Weed Increase Over Time and Control Potential Control Costs Public awareness typically begins Introduction Time Detection

6. A = Alhagi H = Hydrilla P = Peganum From: Rejmanek,M. and M. Pitcairn (2002)

7. Study Conclusions Eradication possible if under 1 hectare 1/3 of infestations between 1 and 100 hectares eradicated ¼ of those between 101 and 1000 eradicated Cost goes up greatly with size SO early detection and rapid response is essential!!!!! Rejmanek and Pitcairn 2002

8. Bradley Method Work in the least invaded areas first, working towards invaded areas Make minimal disturbance – mulch if you must disturb the soil Let native plant regeneration dictate the rate of weed removal – never overclear

9. Manual and Mechanical Hand pulling -can use volunteers -good for small infestations -can have low ecological impact -need to keep equipment clean -minimize disturbance! Mulch! -best for annuals or shallow rooted perennials

10. Weed Wrench

11. Manual and Mechanical Tillage/hoeing Mowing, brush cutting –Best for species that don’t coppice –“controls” – does not eradicate except through repeated use Girdling – remove cambium (do not use on coppicing species, beware creating a hazard tree!) May need to remove stem fragments

12. Mechanical Mulching – bark, hay, cardboard carpet, etc. Flooding/drawdowns Fire

13. Manual or Mechanical Soil solarization – clear or black plastic

14. Manual or Mechanical - kills tissue if around 113-131 degrees F clear plastic more likely to heat to this - soil should be moist - not as good for rhizomatous species - may alter soil biology and chemistry

15. Steam or Hot Water Hot water breaks down the epidermis, the plant becomes dehydrated Waipuna now promoting foam – coconut syrup and water

16. Ultraviolet light: Energy consumption estimates: 10,000 Joule/m2 is enough energy to initiate boiling inside thin leaves. 30,000 Joule/m2 is enough energy to generate steam from the water inside green leaves.

17. Infrared Technology Heats to 1000 o C Bursts cells – stops photosynthesis Not good for deeply rooted species

18. Grazing Can eliminate or encourage invasive plants Can use cattle, goats, sheep, geese, chickens, ducks, etc. Goats eat broadest list of weeds 500 sheep = 4/5 acres/day Need to fence or pen them in May disturb soil, may pass seeds

19. Mechanisms - Herbicides Inhibit respiration –Arsenic compounds –Metallo-organics (also based on arsenics) –Phenols Can be very toxic to mammals

20. Mechanisms - Herbicides Auxins – 2,4,D – causes excess cell division and overgrowth, good on broadleaf weeds, non-persisting, low mammalian toxicity 2,4,5,T – better for woody plants >> has dioxin = Agent Orange, causes cancer Common now: Clopyralid (persists in compost), picloram, triclopyr (Garlon, Brush B Gone)

21. Mechanisms - Herbicides Inhibitors of biosynthetic processes -Cell division – “pre-emergent” -Nucleic acid or protein synthesis inhibitors – “pre-emergent” -Glyphosate – non-selective contact herbicide, interrupts the shikimate pathway – amino acid production pathway not found in animals – “post- emergent,” Rodeo ® used for aquatics

22. Adjuvants Added to facilitate mixing, effectiveness, or application of herbicide “Surfactants,” “spreader-sticker” Usually chemically active, but may be termed “inert” Sometimes included, if not, research to find recommended

23. Considerations using Herbicides Non-target species Use best management practices for handling concentrates Follow ALL laws Must post treated areas Carefully assess site conditions, including weather Likely cannot use volunteers

24. Methods of Application Foliar – spot, boom More herbicide delivered to non-targets May need a surfactant

25. Methods of Application Basal bark 6” band 1’ up stem Must mix with low ester oil Best for smaller shrubs

26. Methods of Application “Hack and squirt” Cut every 2 in or so of stem Good for small trees 4-5” dia Creates hazard trees!

27. Methods of Application Cut stump “Cut and dab” Only need to treat the cambium Apply immediately after cutting Paintsticks handy May need to reapply Not as good in early spring

28. Methods of Application Injected into cambium Can be good for some herbaceous as well as woody Little human contact with herbicide Buy appropriate injectors

29. Reed Canary Grass Phalaris arundinacea Rhizomatous grass Mow 5X +/yr Mulches (+ cardboard) Glyphosate (2%) Shading with plantings

30. Atlantic/English Ivies Hedera hibernica ‘Hibernica H. helix ‘Pittsburg’ H. helix ‘Baltica’ H. helix ‘Star’

31. Ivies Fast-growing ground cover Remove vertical vines first Pull and wad vines on ground Can use string trimmer followed by glyphosate or triclopyr

32. Japanese Knotweed Fallopia japonica Strongly rhizomatous shrub Very hard to kill 2X/month mowing for 3 years Injection – 5 ml of 100% glyphosate Triclopyr or glyphosate

33. Himalayan blackberry Rubus armeniacus Repeated mowing Digging Cut stump, treat with triclopyr or triclopyr + 2,4 - D

34. Iris pseudacorus Yellow flag iris Freshwater aquatic but drought resistant Seeds and rhizomes Dense thickets along shore Dig by hand or machine Cutting + glyphosate

35. Scotch broom Cytisus scoparius Prairies, grasslands Nitrogen-fixer Pull or cut stump Seeds long lived

36. herb robert, stinky bob Geranium robertianum Herbaceous annual Spreads by explosive seeds May be allelopathic Easy to pull Seeds live 5+ yrs

37. hedge bindweed Calystegium sepium Older name Convolvulus sepium Fleshy rhizomes 1-2 ft deep Blankets shrubs Likes wetter soils Responds to triclopyr – pull as much as possible, mulch, then spray as vines grow

38. Conclusions Start with smallest infestations first There are a variety of mechanical and chemical control methods – usually combinations provide the best control For PNW invaders there are a number of strategies for control that must be tailored to the biology of the species