Transcript WEED CONTROL AND LABEL UPDATE IN ALMONDS 2008 North …

POSTEMERGENT WEED
CONTROL AND LABEL
UPDATES IN ALMONDS
2008 North San Joaquin Valley Almond Day
January 22, 2008
Kurt Hembree
UCCE, Fresno County
Postemergent Weed Control Trial in Almonds
Fresno County - 2007
Horseweed*
Treatment
1. Roundup1,2
lb ai/A
Y. Nutsedge*
15 DAT 30 DAT 15 DAT
Crabgrass*
30 DAT
15 DAT
30 DAT
2
7.5
4.7
9.7
8.6
10
9.9
0.75
9.6
9
9.1
8.5
10
9.5
1
9.9
9.8
9
6
10
9
4. Venue1,2
.0028
7.5
6.1
2
0
0
0
5. ACB D331,2
.045
9.9
9.9
1
0
1
0
13
8.8
5.3
5.3
2
5
3
2 + .0028
8.8
7.5
8.2
7.5
9.9
9.7
2 + .045
10
9.9
9
8
10
9.5
2 + .125
8.7
6
9.7
9.3
10
9.8
2+4
8.8
5
9.4
6
9.8
8.5
11. Rely+Venue1,2
1 + .0028
9.9
9.9
9.6
6.5
10
9.7
12. Rely+ACB D331,2
1 + .045
10
9.9
9.6
8.5
10
9.7
13. Rely+Chateau1,2
1 + .125
10
9.9
9.5
8
10
9.8
2. Gramoxone1,2
3. Rely1
6. Scythe1
7. Roundup+Venue1,2
8. Roundup+ACB
D331,2
9. Roundup+Chateau1,2
10. Roundup+Scythe
*Horseweed (8 leaves - bolted), yellow nutsedge (2-6 leaves), crabgrass (2-4 leaves)
Spray volume at 40 gpa, 1AMS added at 8 lb/100 gal, 2Agridex at 1% v/v
4/2/07 – day of application
5/6/07 – 30 DAT
Roundup
Gramoxone
Rely
Venue
5/6/07 – 30 DAT
ACB D33
Scythe
5/6/07 – 30 DAT
Roundup + Venue
Roundup + ACB D33
Roundup + Chateau
Roundup + Scythe
5/6/07 – 30 DAT
Rely + Venue
Rely + ACB D33
Rely + Chateau
Untreated
Postemergence control of horseweed and hairy fleabane
across 4 trials in 2007
10
Control
8
6
4
2
0
RU
GR
RL
ACB
SK
VU
RU +
VU
Horseweed
RU +
ACB
Fleabane
RU +
CH
RU +
SK
RL +
VU
RL +
ACB
RL +
CH
Summary of Postemergent Treatments Since 2005:
• Rely applied alone seems to give the most consistent control of
horseweed, fleabane and other broadleaves, but is somewhat weak on
grasses and sedges. Adding other contacts improves control slightly.
With the recent price drop of Rely, tank-mixing Rely and Roundup may
be the way to go for the most consistent control.
• The PPO herbicides (Shark, Venue, Chateau) should not be used
alone, unless you only have annual broadleaves, and they are very,
very small. Gramoxone usually gives equal to better control. Success
with the PPO products seems to be related to weather conditions.
• Keeping the spray volume up with complete coverage is important.
• ACB D 33 gave exceptional control of horseweed and fleabane when
used alone or mixed with Roundup or Rely.
Herbicide Label Updates and
Improving Product Performance:
• Chateau SW (Valent)
• Matrix FNV (DuPont)
Stanislaus County - May 2007
Roger Duncan
Early signs of wilt
Shoot dieback
Dieback with
mottled leaves
Roger Duncan
Technical bulletin added
to the label in Oct 2007 for
Merced, Stanislaus, and
San Joaquin Counties
Improving preemergent performance
of Chateau:
• A clean soil surface prior to application maximizes control.
• Apply in a spray volume of no less than 30 gpa.
• Using 12 oz in the fall mixed with Prowl H20 or other preemergent
will help broaden the control and get the “toughest” flush of
horseweed and fleabane. If horseweed or fleabane are emerged at
that time, adding 2,4-D or other contact should do the job, making
spring weed control much easier.
• Where purslane is a problem, a second application or delaying
application to just before petal fall can extend control later.
• Don’t expose tree roots to direct contact with the herbicide. If
replanting into treated areas, use clean soil around roots.
Matrix FNV Application Info.
•
Tree age: 1 year
•
Timing: preemergence is it’s strength (2-3 months)
•
Soil surface: free of trash
•
Rate: 4 oz/A/year (broadcast), split-application allowed (2 oz + 2 oz) if
banded and <50% area treated
•
Spray volume: 30-50 gpa
•
Spray Tank pH: 5 - 7
•
Activation: ½ inch rainfall ≈14 days. (apply to moist soil)
•
Chemigation: through micro-sprinklers only
•
Tank-mix partners: other preemergents (Prowl H20); permit if GWPA
regulated product is added; postemergents (RU, Gramoxone, Rely, etc.)
•
Tree injury: likely if under poorly drained conditions and direct root contact?
Weeds controlled preemergence
with Matrix FNV:
Annual Broadleaves:
Dandelion (seedling)
Filaree
Groundsel
Henbit
Mallow
Mustards
Shepherd’s-purse
 Fleabane
 Horseweed
Pigweeds
 Purslane
 Puncturevine
Spurge
Lambsquarters*
Nightshades*
Velvetleaf*
Annual Grasses:
Barnyardgrass
Crabgrass
Foxtails (yellow, green, giant)
Volunteer cereals*
Perennials:
Yellow nutsedge*
Field bindweed*
Johnsongrass*
*Suppression