Comparison of Herbicides, Fabric Discs and Mulches for Preventing Weeds in Nursery Containers

1
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

2
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

3
Experiment Sites

• Site A. CAES Valley Lab (Windsor, CT)
• Azalea (Rhod. Girards 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.

4
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)

5
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 prior
• to first treatment application in 1998
• Windsor - Common Groundsel seed
• Madison - Birdseye Pearlwort seed

6
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

7
STATISTICAL ANALYSES

• Analysis of Variance conducted
• Means followed by the same letter are not
  significantly different (Fishers LSD, p0.05).
• Vigor no transformation
• Weed Counts square root transformation
• Percent Cover arcsine transformation

8
RESULTSPLANT VIGOR
9
AZALEA Vigor (0-10) Windsor 1998
a
a
a
a
a
ab
ab
b
a
a
a
a
a
a
a
b
10
ILEX Vigor (0-10) Windsor 1998
a
a
a
ab
ab
bc
bc
c
a
a
a
a
a
a
a
b
11
AZALEA Vigor (0-10) Windsor 1999
a
a
a
a
a
a
a
b
a
a
a
a
a
a
a
b
12
ILEX Vigor (0-10) Windsor 1999
a
a
a
a
a
a
a
b
ab
ab
ab
ab
b
a
a
c
13
AZALEA ILEX Vigor Windsor 2000
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
b
14
AZALEA Vigor (0-10) Madison 1998
a
a
a
ab
ab
b
c
c
a
a
a
a
a
a
a
b
15
ILEX Vigor (0-10) Madison 1998
a
a
a
ab
abc
bc
c
c
ab
ab
ab
b
a
a
a
a
16
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.

17
RESULTSWEED CONTROL
18
GROUNDSEL (per pot) Windsor 1998
a
b
cd
c
d
e
e
e
19
TOTAL WEEDS (per pot) Windsor 1998
a
b
b
b
bc
cd
d
d
20
TOTAL WEEDS (per pot) Windsor 1998
a
a
ab
ab
bc
c
c
c
21
TOTAL WEEDS (per pot) Windsor 1999
a
a
ab
ab
bc
c
c
c
22
TOTAL WEEDS (per pot) Windsor 1999
a
ab
bc
de
cd
e
cd
e
23
TOTAL WEEDS (per pot) Windsor 2000
a
a
a
ab
b c
cd
cd
d
24
RED MAPLE Seedlings Madison 1998
a
a
b
b
c
c
c
c
25
PEARLWORT ( Area) Madison 1998
a
b
c
d
d
d
d
d
26
PEARLWORT ( Area) Madison 1999
a
a
b
b
b
b
b
b
27
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

28
SUMMARY - EFFECTS ON PLANTS

• 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

29
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?