(mandarin stem-pitting strains) Have you seen this citrus disease? Biosecurity Queensland
What is citrus tristeza virus (CTV)? Mandarin stem-pitting strains of CTV (also called mandarin stem-pitting) are not known to occur in Citrus tristeza virus (CTV) is an economically important Australia. Introduction of mandarin stem-pitting strains disease of citrus that is found worldwide. There are many affecting Imperial, Murcott, Hickson, Ellandale and other different strains of CTV—some are mild and may have no mandarins would have a serious impact on Australia’s visible effect on citrus plants, while other strains can be citrus industry. Mandarin stem-pitting CTV is currently severe and destructive. only known from Indonesia, Japan, Malaysia and Thailand.
Many strains of CTV occur in Australia. Some were There are no impacts on human health from CTV-affected
Departmentof Employment,Development Economic Innovation and introduced as early as the 1860s, along with the plants and fruit. insect that carries the disease—the black citrus aphid (Toxoptera citricidus Kirk). What causes CTV?
CTV is caused by a virus. There are different strains of the virus, each producing a different suite of symptoms on different citrus cultivars and rootstocks. Mandarin stem-pitting strains of CTV are particularly severe on mandarins.
CTV carrying aphids (Toxoptera citricidus Kirk)
Photo courtesy of NSW DPI
CTV grapefruit stem-pitting strain is widely distributed in Australia. CTV sweet orange stem-pitting strains are found only in Queensland where they are under official control. It is illegal to transport citrus budwood or trees Classic stem-pitting symptoms on mandarin in Thailand from Queensland to the other Australian states. Photo courtesy of C. Roistacher
Tomorrow’s Queensland: strong, green, smart, healthy and fair 2 Citrus tristeza virus 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 inthis material The Disclaimer: to Australia. countries nearby from aphid vectors infected carry potentially could also and cyclones storms tropical from dispersal Wind-borne movement. plant illegal for and monitors material plant host of importations approved regulates closely Service and Inspection Quarantine Australian The aphids. CTV-infected with infested material plant of movement the by or material, planting citrus CTV-infected of movement the occur by can spread Long-distance spread? How does CTV strains. stem-pitting mandarin detecting for symptom important most the be will stem-pitting CTV, with associated are symptoms other of arange vigour. While of lack or stunting of andsigns show may brittle become trees infected of and branches twigs but trunk tree the on symptoms visible no external cause may latter The pits. like to many finehoneycomb- small pits afew from vary can It and gumming. to shallow pitting, deep from ranges stem-pitting bark, the Under thickened. abnormally be can Bark and limbs trees. of trunks tree on appearance ‘ropy’ abumpyor cause can CTV stem-pitting Mandarin fruit. small and have stunted generally are CTV severe Trees with like? look CTV does What trees. tangerine or mandarin on detected easily most are CTV of strains stem-pitting Mandarin sensitive. or to tolerant resistant in reaction—from vary but CTV to susceptible are and cultivars species citrus Most Which citrus plants are affected?
There are simple steps you can take to protect your farm: farm: your to take protect can simple you are steps There How can Iprotect CTV? from my farm Innovation). and Economic Development Employment, of Department Queensland, (Biosecurity Pearce and Ceri Industries) Primary of Department (NSW Hardy and Sandra Donovan Nerida Limited), Australia (Citrus Barkley Patricia by Prepared 13 23 25 on Queensland Biosecurity call information, more For information Further 1800 on 084 881 Hotline Pest Plant Exotic 13 on 25 23 Queensland ortheNational Biosecurity Call canproperty—this spread the disease. your off material plant any move not Do Queensland. to Biosecurity immediately them and report CTV, of strains stem-pitting mandarin for lookout the on Be Have you CTV? seen • • • • • B D T until official checks are completed. arecompleted. official checks until plants healthy from stock nursery suspect isolate is detected, CTV stem-pitting mandarin If disease. and pest from free are they that check plants, new any of receipt On diseases. of arange for budwood and seed Auscitrus their test and routinely use that nurseries reputable from material propagation healthy with plantings new establish property, your C R it. spread that insects and the CTV stem-pitting mandarin of symptoms with familiar are workers o eport heck e o
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