How long will it take for the biocontrol agents to control the weed?
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In most cases, establishment
of agents and control of a weed is slow
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Some insect agents that breed fast and disperse fast can control
a weed within a few years
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Fungi are much faster than insects at controlling weeds, they
are usually able to control a weed within a few years
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Short-lived plants, such as ragwort, can be controlled faster
than long-lived plants such as gorse. This is because gorse
plants produce huge numbers of seeds, one individual plant
can produce 20 000 seeds per year and can live for 30 years!
Gorse seeds can survive buried in the soil for more than 40
years, so there are always new seedlings coming up that need to
be controlled.
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Slow is good, though. If weeds are removed too quickly, erosion
can be a problem (lack of soil
stabilisation) or new weeds can take advantage of the empty
space and move in before native plants get a chance to grow.
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Biodiversity
Weed
control Physical
control Chemical
control Biological control How long to
control? Successful
biocontrol 'Useful'
weeds Finding
biocontrol agents Biocontrol
agents in NZ After
control 
