New developments in the weed world

Update on the chemical control of
wilding pines and other developments
“We can’t solve problems by using the same kind of
thinking we used when we created them?”
(attributed to Albert Einstein)
1. Boom spraying of wilding pines
• The operational use of
TDPA with Punch
Penetrant consistently
giving excellent results if
applied properly.
• After a field visit, the EPA
now understand the
problem we are dealing
with.
• However, the EPA still
have concerns because of
high rates of active
ingredients used.
Regarding some of the the EPA
concerns what have we found?
• All herbicides, but
especially triclopyr, are
persistent in the leaf litter
in significant quantities
and are released slowly
into the soil as the
needles decay.
• Triclopyr is present in the
soil at relatively high
levels 3 years after the
boom spraying was done
(2013).
(Hanmer data – Clayson Howell).
But is this all that bad?
• Duane Peltzer mentioned on the
radio that mycorrhizae are a key
factor for wilding pines to
become established.
But…
• It has been found that triclopyr
inhibits the growth of mycorrhizal
fungi (J. Pesticide Reform, 2000,
Vol. 20 No. 4).
So…
• Maybe the persistence of
triclopyr in the soil helps prevent
wildings from becoming
established for longer?
Mountain beech trees
• Beech trees sowed 12 months after
treatment.
• After 3 years no flush of Pinus
contorta (residual triclopyr?).
• Hares, rabbits and deer eat exposed
beech trees.
• Good survival of mountain beech in
closed cages (strong exclosure
effect), even without mycorrhizae.
• Survival of beech trees is greatest in
treated plots - probably because of
greater light availability and wetter
soils (i.e. pines very effective shading
and at drawing down soil moisture to
low levels).
(Hanmer data: Clayson Howell)
Research to address the EPA concerns
• DOC have committed to
doing dose response
tests to determine
whether good kills
(>95%) can still be
achieved using TDPA at
lower rates.
• A single half dose TDPA
trial was installed this
year as a precursor to
more comprehensive
trials being done next
year.
• As per my proposal last
year, has a decision
been made regarding
forming a consortium to
fund future herbicide
research?
New boom spray herbicide trials
•
•
•
•
BASF contracted DOC to install trials
on Pinus contorta using Sharpen
contact herbicide (saflufenacil)
together with half strength TDPA and
metsulfuron-methyl herbicides.
ETEC contracted DOC to install trials
using agent 006, also a contact
herbicide, alone or together with
Grazon on Pinus contorta.
We are also comparing efficacy of
Sharpen and diquat as a contact
herbicides for sites infested with small
trees but supporting native woody
vegetation which we want to retain.
First monitoring of these trials is to
occur January 2017.
2. Basal bark – wet tree trials
• ETEC have developed a new
formulation of X-Tree Basal that
supposedly can kill wet trees.
• Initial trials of three different
formulations against standard
X-Tree Basal were installed in
January 2015.
• All the wet trees and dry trees
treated with these three
formulations died, but not wet
trees treated with standard XTree Basal.
• In May DOC are installing a
large trial using these
formulations to determine
whether the herbicide mixture is
fit for purpose.
Any questions?