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North West Weeds |
Identification │ The problem │ Locality Map │ Control methods │Using pesticides │Disclaimer
Harrisia cactus is spread by seed. The plant can begin to produce seed at age 6 months and from then on can continue to produce fruit almost all year round. Each fruit contains about 800 seeds encased in a sweet, sugary substance which is extremely popular with birds, emus and pigs.
Harrisia cactus can cause painful injury to animals or humans who accidentally walk into or otherwise touch a plant. It is a prolific seeder, spreads quickly, and has the ability to eventually take over large areas of grazing country. CONTROL METHODS Ploughing is probably the only means of eradication. Harrisia cactus cannot survive on lands under constant cultivation [NB. State laws apply in respect of land clearing.] Burning. Tops of plants are easily killed, butts go deep into the ground and therefore require extra heat. Burning is really only appropriate for small infestations. [NB. Subject to compliance with local bushfire restrictions]. Biological control using a mealybug (Hypogeococcus festerianus) has been effective in warmer areas of Queensland and is now being used with varying degrees of effectiveness to control Harrisia infestations in New South Wales. The insects have to be manually transferred into uninfected plants. The main problem with biological control is that the mealybug does not have the capacity to spread as efficiently as do new seedling plants. The seeds can be spread kilometres by birds and animals, whereas the mealybug can only travel a matter of metres. And, cactoblastis or cochineal are INEFFECTIVE on Harrisia cactus. Chemical treatment is effective, but must be regularly undertaken. According to NSW DPI’s excellent booklet “Noxious and Environmental Weed Control Handbook 2004/2005”, herbicide treatments registered for use in New South Wales include:
NB Most Harrisia cactus in New South Wales is found near the border with Queensland, mainly in the Boggabilla area. For those NSW property owners who also have land north of the border, please note there are a number of chemicals registered for use in Queensland only. These include Tordon DSH® (2.5 L/100 L water) and Lantana DP 600® (1L/60 L water). Check labels for full directions. IMPORTANT: USE OF PESTICIDES – ALWAYS READ THE LABEL Pesticides must only be used for the purpose for which they are registered and must not be used in any other situation or in any manner contrary to the directions on the label. Never use a herbicide in any way contrary to the label recommendations. Queensland Department of
Primary Industries has had a long involvement with managing this predominantly
Queensland cactus… see their informative webpage
www.nrm.qld.gov.au/pests/weeds/
DISCLAIMER: The information contained in this
web site is based on knowledge and understanding at the time of writing.
However, because of advances in knowledge, users are reminded of the need to
ensure that information upon which they rely is up to date and to check currency
of the information with the appropriate officer of North West Weeds or the user’s independent adviser. | |||||||||||||||
Send mail to
lestanner@aapt.net.au with questions or comments about this web site.
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