canker Have you seen this citrus disease? Biosecurity Queensland

What is ?

Citrus canker is a damaging bacterial disease of citrus and some other in the family . Citrus canker can have a serious impact on and Employment,Development Economic Innovation and Australia’s valuable citrus export industry.

Outbreaks of this disease have previously occurred in Australia in Queensland and the Northern Territory.

Departmentof The last outbreak at Emerald was successfully eradicated, but at great cost to growers, associated industries and government. We need your help to detect any future outbreaks. Scab-like lesion on fruit

Photo courtesy of DEEDI What causes citrus canker? Which hosts are affected? Citrus canker is caused by the bacterium Xanthomonas citri subsp. citri. Infected can develop unsightly All citrus can be affected (e.g. , , lesions on leaves, fruit and stems. infected with , , mandarin, , , the disease may be unthrifty with low yields and poor and ). However, some cultivars of citrus quality fruit. more readily develop canker lesions than others.

Citrus canker is a plant disease and is not harmful to Citrus canker can also affect some native Australian people or animals. Rutaceae species, such as (desert lime), Acronychia acidula (lemon aspen), Micromelum minutum (lime berry) and Murraya paniculata var. ovatifoliolata (native mock orange).

Other plants such as wampee (Clausena lansium), white sapote (Casimiroa edulis) and elephant apple (Feronia limonia) are also known hosts.

Scab-like or corky lesions on fruit and leaves

Photo courtesy of C. Pearce

Tomorrow’s Queensland: strong, green, smart, healthy and fair 2 Citrus canker Photo courtesy of DEEDI of courtesy Photo affected. is severely foliage the where in cases seen only typically are stems or lesions fruit on Multiple bacteria. the for point an entry provides wound the where leaf miners, citrus of tracks feeding the follow can tips) or or leafalong (such leaf margins the on as pools water where occur in clusters canker lesions often Citrus and stems. fruit lesions leaves, on miner blister-like of channels), development the causing leaf such as wounds (mechanical wounds or insect or stomata the through tissue plant enters bacterium The What does citrus canker look like? Scab-like or corky lesions on fruit on lesions corky or Scab-like • • • which can fall out to create a‘shot-hole’ to create appearance. out fall can which centre, older or lesions haveacrater-like may Large age. lesions the halo or as ring ayellow become can that margin an oily, by water-soaked surrounded are Lesions to brown. tan and coloured raised usually are Lesions Photo courtesy of A. Miles, DEEDI Miles, A. of courtesy Photo DEEDI of courtesy Photo Citrus canker on leaves and stem and leaves on canker Citrus Citrus canker lesion on a leaf showing the yellow ring or halo ringor yellow the showing aleaf on lesion canker Citrus 3 Citrus canker approved host plant imports. plant host approved and regulates movements plant illegal for monitors closely Service and Inspection Quarantine Australian The into Australia. thisdisease introducing of risk greatest the poses material plant infected of importation Illegal further. disease the spread also can present), are and rain winds strong (where events weather severe during debris or an aerosol as bacteria of movement airborne or material, plant infected of Movement and clothing). shoes (hands, and people equipment) gardening sprayers, mechanical hedgers, tools, (vehicles, equipment on distances longer over spread be canker can Citrus systems. irrigation overhead or splash rain by spread be ooze can thisbacterial distances short Over wet. when canker lesions ooze bacteria The How is citrus canker spread? 2009. in canker citrus of free declared was area This 2005. in May Queensland, in Emerald, detection last the with rare, are in Australia canker. Outbreaks citrus of free is currently Australia world. the of areas citrus-growing subtropical and in many tropical is widespread disease The Where does citrus canker occur? There are simple steps you can take to protect your farm: your to take protect can simple you are steps There canker? citrus How can Iprotect from my farm DEEDI Pearce, C. of courtesy Photo Citrus canker lesions on upper and lower leaf surfaces leaf lower and upper on lesions canker Citrus • • • • or unfamiliar symptoms. unusual any and report orchard your check Regularly canker. citrus of symptoms the with familiar are workers farm and your you Make that sure soapy water. in hot washed havebeen they after until orchard your into clothes canker, travel your wear not do citrus has that country to an overseas havebeen you If farm. your enters it is equipment clean before sure Make diseases. spread can vehicles and equipment visitors, –workers, Remember practices. hygiene and sanitation clean. good Use farm your Keep completed. are official checks until plants healthy from stock nursery suspect isolate canker is detected, citrus If free. and disease pest are they that check plants, new any of receipt On diseases. of arange for tested is which routinely and budwood, seed Auscitrus use that nurseries reputable from material plant healthy with plantings new establish property, canker to on your To citrus introducing avoid 4 Citrus canker It is intended as a guide only. aguide as intended is It publication. of time the at available recent information most the from prepared was publication in this material The Disclaimer: and Innovation).Development Economic Employment, of Department Queensland, (Biosecurity Pearce and Ceri Miles and Andrew DPI) (NSW Hardy Sandra Ltd), Australia (Citrus Barkley Pat by Prepared website at www.biosecurity.qld.gov.au 13 on 25 23 our Queensland visit or Biosecurity Call information Further 1800 on 084 881 Hotline Pest Plant Exotic 13 on 25 23 Queensland ortheNational Biosecurity Call Queensland. to Biosecurity them andreport immediately and twigs canker-like fruit, lesions leaves, on citrus for Watch out disease. the of cases suspect to report obliged are owners property means that This 1989 Act Plant Protection under the regulated pest anotifiable as canker is declared citrus Queensland, In Have you citrus seen canker? . .

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