Comparison of Herbicides, Fabric Discs and Mulches for Preventing Weeds in Nursery Containers TIM ABBEY and TODD MERVOSH The Connecticut Agricultural Experiment Station - Windsor, CT
Comparison of Herbicides, Fabric Discs and Mulches for Preventing Weeds in Nursery
Containers
TIM ABBEY and TODD MERVOSH
The Connecticut Agricultural
Experiment Station - Windsor, CT
BACKGROUND
USDA Northeast Regional IPM Project
(1998-2000):
Non-chemical weed management options for container-grown woody ornamentals.
- Fabric discs (Geodiscs)
- Mulches (Pine Bark, Cocoa Hull), Corn Gluten Meal
Experiment Sites
Site A. CAES Valley Lab (Windsor, CT):• Azalea (Rhod. ‘Girard’s Pleasant White)• Winterberry Holly (Ilex verticillata ‘Winter Red’)
Plants provided by Planters’ Choice Nursery
Site B. Summer Hill Nursery (Rockland, CT):• Azalea (Rhod. poukhanense ‘Compacta’)• Winterberry Holly (Ilex verticillata ‘Red Sprite’)
Plants provided by Summer Hill Nursery
All plants newly potted in 2-gallon containers.
TREATMENTS
1. UNTREATED CHECK
2. GRANULAR HERBICIDE:Ornamental Herbicide 2 (100 lb/A)
Oxyfluorfen (2 lb/A) + Pendimethalin (1 lb/A)
3. SPRAYABLE HERBICIDE: I. Gallery 75DF (1 lb/A) + Pendulum 60DG (5 lb/A)
Isoxaben (0.75 lb/A) + Pendimethalin (3 lb/A)
II. Gallery 75DF (1 lb/A) + Surflan AS (2 qt/A)
Isoxaben (0.75 lb/A) + Oryzalin (2 lb/A)
TREATMENTS
4. FABRIC DISC (GEODISC): 9” diameter
5. PINE BARK MULCH: 1” layer
6. COCOA HULL MULCH: 3/4” layer
7. CORN GLUTEN MEAL: 650 lb/A (3.0 g / pot)
Weed seed sown over potting mix surface priorto first treatment application in 1998:
Windsor - Common Groundsel seed
Madison - Birdseye Pearlwort seed
TREATMENT APPLICATIONS
1998 Mid MAY - Applied All Treatments Mid AUGUST - Reapplied Herbicides & C.G.M.
1999 Mid APRIL, Early JULY, Early OCTOBER -
Applied Herbicides & C.G.M.
Weeds Present (counted & removed at each rating):
Windsor - Groundsel, Bittercress, Oxalis, Horseweed
Madison - Red Maple seedlings, Pearlwort
STATISTICAL ANALYSES
• Analysis of Variance conducted
• Means followed by the same letter are not significantly different (Fishers LSD, p=0.05).
• Vigor – no transformation
• Weed Counts – square root transformation
• Percent Cover – arcsine transformation
RESULTS:
PLANT VIGOR
AZALEA Vigor (0-10): Windsor 1998
4
5
6
7
8
9
10C
HE
CK
Gal
l +P
end
OH
-2
Geo
disc
pinn
ed
Geo
disc
no p
in
Pin
e B
ark
Coc
oaH
ull
CG
M
3 WAT 13 WAT
a aa a a a ab
aa
a a
ab
ab
a
b
ILEX Vigor (0-10): Windsor 1998
4
5
6
7
8
9
10C
HE
CK
Gal
l +P
end
OH
-2
Geo
disc
pinn
ed
Geo
disc
no p
in
Pin
e B
ark
Coc
oaH
ull
CG
M
3 WAT 13 WAT
a aa a a a ab
ab
bc
aab
bc
a a
c
AZALEA Vigor (0-10): Windsor 1999
4
5
6
7
8
9
10C
HE
CK
Gal
l +S
urf
OH
-2
Geo
disc
pinn
ed
Geo
disc
no p
in
Pin
e B
ark
Coc
oaH
ull
CG
M
5 WAT-1 6 WAT-2
a aa a a a ab
aa a
a
a
aa
b
ILEX Vigor (0-10): Windsor 1999
4
5
6
7
8
9
10C
HE
CK
Gal
l +S
urf
OH
-2
Geo
disc
pinn
ed
Geo
disc
no p
in
Pin
e B
ark
Coc
oaH
ull
CG
M
5 WAT-1 6 WAT-2
bab
ab a
ab a
abc
aa
aa a
aa
b
AZALEA & ILEX Vigor: Windsor 2000
4
5
6
7
8
9
10C
HE
CK
Gal
l +S
urf
OH
-2
Geo
disc
pinn
ed
Geo
disc
no p
in
Pin
e B
ark
Coc
oaH
ull
CG
M
AZALEA ILEX
a aa a a a ab
aa a
a a aa
a
AZALEA Vigor (0-10): Madison 1998
4
5
6
7
8
9
10C
HE
CK
Gal
l +P
end
OH
-2
Geo
disc
pinn
ed
Geo
disc
no p
in
Pin
e B
ark
Coc
oaH
ull
CG
M
3 WAT 14 WAT
a aa a a a ab
b
a a a ab
c
ab
c
ILEX Vigor (0-10): Madison 1998
4
5
6
7
8
9
10C
HE
CK
Gal
l +P
end
OH
-2
Geo
disc
pinn
ed
Geo
disc
no p
in
Pin
e B
ark
Coc
oaH
ull
CG
M
3 WAT 14 WAT
ab ba a a
ab a
ab
c
abc
a
bc
a aab
c
Madison site – 1999
• Several azaleas were discarded by nursery personnel during 1999. Thus, plant vigor data in 1999 at the Madison site has not been presented.
• Many discarded azaleas that had died were ones that had been fitted with Geodiscs.
• An explanation for the death of these plants could not be determined.
RESULTS:
WEED CONTROL
GROUNDSEL (per pot): Windsor 1998
0
10
20
30
40
50
60
70C
HE
CK
Gal
l +P
end
OH
-2
Geo
disc
pinn
ed
Geo
disc
no p
in
Pin
e B
ark
Coc
oaH
ull
CG
M
6 WAT-1a
e
d
e
cd
c
b
e
TOTAL WEEDS (per pot): Windsor 1998
0
2
4
6
8
10
12C
HE
CK
Gal
l +P
end
OH
-2
Geo
disc
pinn
ed
Geo
disc
no p
in
Pin
e B
ark
Coc
oaH
ull
CG
M
13 WAT-1a
d
b
dcd
bc
bb
TOTAL WEEDS (per pot): Windsor 1998
0
5
10
15
20
25C
HE
CK
Gal
l +S
urf
OH
-2
Geo
disc
pinn
ed
Geo
disc
no p
in
Pin
e B
ark
Coc
oaH
ull
CG
M
10 WAT-2
a
cc c
bc
ab
a
ab
TOTAL WEEDS (per pot): Windsor 1999
0
10
20
30
40
50C
HE
CK
Gal
l +S
urf
OH
-2
Geo
disc
pinn
ed
Geo
disc
no p
in
Pin
e B
ark
Coc
oaH
ull
CG
M
5 WAT-1a
cc
bc
ab
ab
a
c
TOTAL WEEDS (per pot): Windsor 1999
0
5
10
15
20
25C
HE
CK
Gal
l +S
urf
OH
-2
Geo
disc
pinn
ed
Geo
disc
no p
in
Pin
e B
ark
Coc
oaH
ull
CG
M
11 WAT-1
ab
e
de
e
bc
cd c
d
a
TOTAL WEEDS (per pot): Windsor 2000
0
2
4
6
8
10
12
14C
HE
CK
Gal
l +S
urf
OH
-2
Geo
disc
pinn
ed
Geo
disc
no p
in
Pin
e B
ark
Coc
oaH
ull
CG
M
5/31/00
a
cd
d
cd
ab
a
a
bc
RED MAPLE Seedlings: Madison 1998
0
2
4
6
8
10
12C
HE
CK
Gal
l +P
end
OH
-2
Geo
disc
pinn
ed
Geo
disc
no p
in
Pin
e B
ark
Coc
oaH
ull
CG
M
6 WAT-1a
c
b
c c c
a
b
PEARLWORT (% Area): Madison 1998
0
10
20
30
40
50
60
70
80C
HE
CK
Gal
l +P
end
OH
-2
Geo
disc
pinn
ed
Geo
disc
no p
in
Pin
e B
ark
Coc
oaH
ull
CG
M
14 WAT-1a
d
c
d d d
b
d
PEARLWORT (% Area): Madison 1999
0
5
10
15
20
25C
HE
CK
Gal
l +S
urf
OH
-2
Geo
disc
pinn
ed
Geo
disc
no p
in
Pin
e B
ark
Coc
oaH
ull
CG
M
12 WAT-2a
bb
bb
b
a
b
WEED PREVENTION: 1999 SUMMARY
OH-2 Very Good
Gallery + Surflan Good
Geodiscs Excellent
Pine Bark mulch Fair
Cocoa Hull mulch Fair
Corn Gluten Meal Poor
• OH-2: Minor Injury to Winterberry
• Gallery + Pendulum:
Injured Azalea, Winterberry (esp. at Windsor)
• Geodiscs: Excellent Plant Vigor (except Azalea at Summer Hill late in 2nd year)
• Pine Bark Mulch: Good Plant Vigor
• Cocoa Hull Mulch: Generally Good Plant Vigor
• Corn Gluten Meal: Excellent Plant Vigor
SUMMARY - EFFECTS ON PLANTS
GEODISC FABRIC DISCS
• Provided comparable or superior weed prevention than standard herbicide treatments in containers.
• Ideal for single-stem plants that are sensitive to herbicides (hydrangeas, EACs, etc.).
• Stayed intact for at least 2 years - Reusable?
Potential Limitations:
• Expensive for large-scale use
• Need proper fit in containers, blow-out potential
• Death of azaleas at one of two sites… Explanation?