Factsheet 245 Phytophthora Dieback
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factsheet 245 Phytophthora Dieback Before felling a dead stringybark in the Adelaide Hills The tree may be infected by Phytophthora, a particularly infectious disease that readily spreads by human activity. Even the sawdust on your chaps can spread the disease to an uninfected site What is Phytophthora? Phytophthora (pronounced FY-TOFF-THORA) species are soil and waterborne fungi that cause disease and often death to a wide variety of native plant species, exotic fruits and vegetables as well as ornamental plants like Camellia. A group of dead or dying susceptible plant species is generally a good indication of Phytophthora infestation. Phytophthora attacks the roots and stems of plants. Early symptoms of the disease are rootrot, and depending on the plant species, stem rot and eventual death. In effect, the susceptible plants die from an inability to take up sufficient water and nutrients. The best indicator species for the disease in South Australia is the yacca or grass-tree Xanthorrhoea sp., as it is highly susceptible. Other susceptible species are messmate stringybark Eucalyptus obliqua, brown stringybark E baxteri, Banksia sp., myrtle wattle Acacia myrtifolia, cone-bush Isopogon ceratophyllus, beaked hakea Hakea rostrata, and the Mount Lofty bush-pea Pultenaea involucrata. Symptoms The first symptoms of infection are yellowing of the foliage followed by dieback of the entire plant. In the Adelaide Hills, Stringybark (Eucalyptus baxteri and E.obliqua) are most sensitive to dieback. Dead trees often appear in groups, with the most recently affected trees partly defoliated and down slope from earlier deaths. Not all individual plants will be attacked at the one time in a diseased area Diseased plants show discolouration in the foliage, most commonly reds and yellows. Sapwood of infected trees is often stained orange-red (healthy sapwood is cream coloured almost the same shade as heartwood). Sharp disease fronts or boundaries between healthy and diseased vegetation may be present How does Phytophthora spread? Phytophthora can spread from plant to plant through root contact. It is spread most rapidly when rainfall coincides with warm temperatures, generally in spring, summer and early autumn. The disease can spread very quickly with the help of ‘artificial’ factors such as human disturbance. The transport of infested soil and plant material by vehicles and heavy machinery (such as logging and roadworks) is probably the single most important factor in the spread of this fungus. A vehicle not cleaned after working in an infested area can easily spread the disease to an uninfested site many kilometres away. The disease spreads by transferring mud on boots and tyres. For tree workers, the disease can be transported in sawdust on a chainsaw and chippers, and by mud on stump grinders. There is no cure for Phytophthora, nor is there any way of stopping its spread once it has infested an area. We can, however, slow down its movement, and minimise its introduction into new areas by modifying the way we behave in Phytophthora prone areas. How you can help stop the spread of Phytophthora. The best way to control the fungus is to prevent the transfer of infested soil or plant material. • Avoid driving, working or walking in areas when soils are wet and sticky. • Stay on designated roads and tracks. Vehicles and people moving off roads into infested areas may pick up infested soil and transfer it to uninfested areas. • Brush soil off vehicles, bikes, boots and equipment before and after each trip. Do not take them home to clean. • Obey road signs. Roads and tracks may be closed, sometimes permanently, to help stop the spread of Phytophthora. • Use wash down or hygiene stations when provided. Activities that are at Risk of spreading Phytophthora All activities that involve movement of soil, water and plant material (whether deliberately or accidentally) have the potential to cause the spread of Phytophthora. Moist soil and plant material readily adhere to machinery, equipment, tyres, tools and footwear. STANDARD OPERATING PROCEDURES in Phytophthora infected areas These hygiene procedures are crucial to contain further spread of Phytophthora. ‘High Risk Zones’ have Phytophthora contamination confirmed from site observation and/or testing. ‘Moderate Risk Zones’ may still have Phytophthora contamination. Tree & stump removal Tree removal should be performed only during dry soil conditions Avoid working during wet months, generally April to October Disinfect all tools & footwear before leaving site. Use methylated spirit in laundry sprayer. Petrol is a useful substitute Minimise soil disturbance Do not grind stumps in high risk zones Preferably excavate & burn stumps on site Foliage, logs and plant material greater than 1 metre above ground are generally considered to be Phytophthora free and can be chipped and removed providing there is no adhering soil. Chipper & Stump grinders must be free of soil and plant material before leaving infected site. Disinfect with chlorine bleach 1:4 or 1kg pool chlorine on 15L water in backpack sprayer. Leave for 20 minutes. When leaving ensure footwear is free of mud and soil • maintain familiarity with this SOP and amendments including the Phytophthora Register and High Risk Zone map; • provide relevant information from this SOP to contractors, staff and visitors under each staff member’s direction; • carefully plan all outside activities through familiarizing yourself the Phytophthora status of sites intending to visit and/or work at; • plan work / visits and travel through Moderate Risk sites first, before moving to High Risk sites. Never do the reverse unless you ‘clean down’ • always carry a 'Phytophthora Hygiene Kit' in working order on all occasions when a vehicle likely to enter or travel through a 'High Risk' zone; • report any group of sick, dying or recently dead plants to Council's nominated Phytophthora contact person. In particular keep an eye on Yaccas & Banksias; • apply the following rules as appropriate for wet and dry soil conditions within High and Moderate Risk zones; and • thoroughly clean footwear, vehicles, equipment and machinery as a quarantine measure every time as required in this SOP. There are no exceptions! CLEAN DOWN on SITE Dry Clean in preference, placing particular attention on earthmoving machinery, tracked vehicles & vehicles with protection plates (soil and roots cling to undercarriage & mudflaps). Decide firstly whether to dry clean or wash down. Always apply appropriate occupational health & safety precautions. Machinery, Vehicles and Equipment Cleaning materials • compressed air and/or high pressure water (where available and applicable) • broom, shovel and steel rod (such as a crowbar) • cleaning / disinfecting chemicals • large container, eg bucket (to mix disinfectant solution) • Pay particular attention to mudflaps and tyres Vehicle Tyres and Footwear Cleaning materials Phytophthora Hygiene Kit containing … • flagging tape and screwdriver • hard hand 'scrubbing' brush • bottle of disinfectant (Methylated Spirits) & spray bottle Cleaning Steps under Dry Conditions … 1. Cleandown within ‘Risk’ zone just worked, on formed and impervious surface. Mark off the area with flagging tape. 2. Remove clumps of soil and plant material with a scraper. 3. Remove remaining soil & plant material from the scraper, brush and footwear with stiff brushing or compressed air. 4. Disinfect any remaining material lodged in places difficult to access. Cleaning Steps under Damp Conditions … 1. Use allocated wash down site 2. Add 'fungicide' such as Phytoclean® or Coolacide® to water at label-recommended rates. 3. Wash (preferably high pressure) vehicle & machinery to remove soil & plant material. 4. Clean vehicle / machinery tyres or tracks as they leave wash down adjoining road surface. 5. Clean and disinfect footwear sole then brush with Methylated Spirits then allow it to dry. PHYTOPHTHORA 'HIGH RISK' ZONES ~ - Roads, Reserves & Adjoining Properties Adelaide Hills Council Road or Reserve Location Km/Ha District Bagshaw Road Kent Rd to Adelaide Gully Rd 3.1 Kersbrook Bassnet Road Karwin Rd to Para Wirra Rd 8.3 Humbug Scrub to Williamstown Black Snake Road Lucky Hit Rd to Cromer School Rd 1.8 Cromer Blackburn Drive Shurdington Road to St Barberie Drive 0.2 Crafers Brown Road Entire length 1.3 Scott Creek Burns Road reserve Inglewood Camac Road Greenhill Rd to Kerr Rd 0.2 Balhannah Carthew Road Entire length 1.1 Scott Creek Cemetery Road Entire length 0.4 Scott Creek Centre Court Entire length 0.2 Humbug Scrub Charlick Road Hillcrest Ave to Manna Gum Lane 0.5 Crafers West Coach Road Entire Closed section only 2.0 Greenhill / Norton Summit Colonial Drive Green Valley Rd to Moores Rd 1.4 Norton Summit Cromer Road Lucky Hit Rd to Pontt Rd 2.5 Cromer Cromer School Road Cromer Rd to Black Snake Rd 1.0 Cromer Darpuna Road Entire length 0.7 Bridgewater Deloraine Road Watts Gully Rd to The Nuggett Rd 0.9 Warren Elmstead Drive Entire length 0.5 Upper Sturt Emmett Road Entire length 2.2 Crafers West Fernwood Way Entire length 0.6 Upper Sturt Green Road Institute Rd to Moores Rd 1.4 Montacute Greenhill Road Summit Rd to Quintin Ave 2.1 Greenhill Greenhill Road Kerr Rd to Camac Rd 0.5 Balhannah Gum Flat Road Jarrett (unmade) Rd to Tanahmerah Rd 0.8 Balhannah / Carey Gully Gurr Road Entire length 1.3 Scott Creek Hadrians Gully Road Entire length 1.7 Scott Creek Hawk Hill Road Entire length 0.7 Crafers West Hill Street Victor Harbor Hillcrest Avenue SE Freeway interface to Emmett Rd 0.7 Crafers