North West Weeds
Your local guide to local noxious weed control (NSW, Australia)
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North West Weeds |
Photo, right: An example of how large velvety tree pear can grow - former Prickly-pear Destruction Commission officer Kevin Whitton standing underneath a patch of velvety tree pear on the property "Monkstadt", located between Bonshaw and Tenterfield, NSW - circa 1985. The plentiful seeds of velvety tree pear are spread over long distances by birds. Plants grow into large trees up to 5m high, and groups of plants become so thick they impede stock movement and eliminate useful grasses. On the credit side, however, velvety tree pear has some value as supplementary fodder during dry times. Although the plant certainly has plenty of thorns, they are not as severe as those on most other cactus species.
IDENTIFICATION
CONTROL METHODS Biological control
Cochineal insects (Dactylopious opuntiae)
can be very effective. BUT, the insects have limited mobility and
sometimes need to be manually transferred into new areas and/or isolated
plants. They can be carried long distances by strong winds but on their own the tiny in The insects work better if they are given shelter from the elements. After the insects are established on the plant itself, the biocontrol program can be further assisted by cutting some of the main plants down (about 300mm above ground level). Ideally, try to land these plants on rocks/logs to minimise their contact with the soil and their ability to take root. Those parts of the plant that break away when the plant hits the ground should be stacked back around the base of the main plant - especially if they landed on good soil.
Maintaining supplies of biocontrol agents for the future? The ongoing presence of velvety tree pear provides host material for cochineal (the same species also attacks the more aggressive common pest pear). It also provides an option for desperate cactoblastis moths unable to locate their favoured common pear on which to lay their eggs - the young leaves are soft enough for the cactoblastis to enter and eventually complete their life cycle, thus paving the way for their next generation. While cactoblastis larvae will demolish thousands of young seedlings in some seasons, they have zero impact on large plants because the basic material is too hard. Chemical treatment of velvety tree pear is effective, because the plants are easy to find. Unfortunately the work can be costly because of the volume of herbicide needed to cover the plants. According to NSW DPI’s excellent booklet “Noxious and Environmental Weed Control Handbook 3rd Edition", and other sources, herbicide treatments include:
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. Cochineal.htm on this website. Information on other individual prickly pear species is also included in this website. Return to Weeds List for rope pear, harrisia, prickly pear history etc. 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. LRT 0/09/09 |
Send mail to
northwestweeds@aapt.net.au with questions or comments
about this web site.
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