Understanding the mechanisms behind the development of herbicide resistance can be difficult'

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A guide to understanding Herbicide Resistance

• Understanding the mechanisms behind the
  development of herbicide resistance can be
  difficult.

• The following interactive display notes
  demonstrate visually and simply the relationship
  between

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herbicide attachment
and effect of natural gene mutations in a weed

• At the conclusion of the display, the development
  of herbicide resistance should be less of a
  mystery.

• During the display, you will be required to press
  either the left mouse button or down arrow key to
  continue the display when the weed symbols
  or appear.

Lets take a look.
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An enzyme carries out work in plant cells that
are essential to normal plant growth and
development.
Enzyme target sites allow specific substances
attach to the enzyme. When a chosen herbicide is
applied, it binds to a specific target site and
the weed dies as the enzyme is unable to do its
work in the plant cell.
The following diagrams simply represent how via a
natural gene mutation, the enzyme target sites
change shape and herbicide resistance can result.
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If there is no known herbicide resistance..
I. All herbicide options could be available to
control the weed
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Herbicide options
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Here are examples of a weed with multiple
herbicide resistance
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Here is an example of a weed with cross herbicide
resistance
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How can the onset of herbicide resistance be
slowed?

• Create a weed management plan
• range of strategies
• flexible
• reviewed revised regularly

Weed management strategies
Crop pasture phases
Rotate
Investigate various weed management strategies
Only spray small weed numbers
Herbicide Groups
In this way, we integrate many ways of managing
weeds into a planned, but flexible
approach. I.W.M. - it doesnt stand for Ignoring
Weed Management
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Feel like the mechanisms of Herbicide Resistance
are not such a mystery?
Want to know more about reducing the onset of
herbicide resistance or its management? Further
information and a handout can be obtained from
the Cooperative Research
Centre for Australian Weed Management
Website www.weeds.crc.org.au Postal
addressCRC for Australian Weed Management,
PMB1 Waite Campus Glen Osmond, SA
5064 Telephone [phone]
Produced by Annabel Bowcher, Education Officer
Weeds CRC, 2002