PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
Table 77. Total vegetation control.
What to use?
When and how to apply?
RESIDUAL WEED CONTROL---------- 6-12 MONTHS
Not for use near desired plants or on areas where For long term weed control there are “once-a-year
their roots may extend, or water catchments areas. They pathweeders” registered for home gardeners, which
are only suitable for relatively flat areas where there is no
chance the chemicals can wash down slopes to garden
beds or lawns and leave lasting damage.
These chemicals are suitable for use along log barriers,
crash rails, drain headwalls and fencelines, generally not
in domestic or residential areas.
Soil residuals must be used at recommended rates to
obtain the desired length of control. Many of these
herbicides at higher concentrations provide control for a
much longer time so that the area of land to which they
are applied is not available for other uses for that period
of time.
Post-emergent (knockdown) eg
Group M, eg Roundup (glyphosate)
Soil residual, eg
Group C, eg Gesatop (simazine)
have a residual effect for up to 12 months and
prevent weeds growing in paths, driveways and
paved areas.
Some may be mixed with a post-emergent
(knockdown) herbicide, eg Roundup , Tryquat .
Always check the label to see that mixtures
are compatible.
Remember no pre-emergent herbicide will control all
germinating weeds.
Systemic, foliage absorbed, non-selective herbicide
translocated down into roots, kills emerged weeds.
Soil residuals
Residual weed control for 6-12 months.
RESIDUAL WEED CONTROL---------- 1 YEAR OR LONGER
Not for use near desired plants or on areas where
their roots may extend.
The herbicide must be used at the recommended rate
to obtain control for this period of time.
May be used in parking areas (not domestic or
residential).
Soil residuals, eg
Group C, eg Diuron (diuron)
Weed control can be obtained for about 1-2 years.
OR
Group C, eg Gesatop (simazine)
OR
Group O, eg Casoron , Sierraron (dichlobenil)
Weed control can be obtained for several years.
Weed control can be obtained for several years.
Fig. 252. Example of herbicide injury. Left: Soil residual applied to path washed down slope onto turf. Centre: Preemergent
simazine injury to Prunus, applied just before heavy rain, interveinal yellowing can range from relatively mild to
severe depending on the amount of herbicide absorbed. Right: Leaf veins of citrus turn yellow or white (vein clearing),
possibly bromacil or diuron injury; note that vein clearing may also be caused by other agents, eg virus disease, root injury or
girdling, or arguably, if normally well fertilized trees are suddenly deprived of nitrogen. PhotoCIT, Canberra (P.W.Unger).
Weeds - Examples of weed situations 459