Management of Silvery Thread Moss (Bryum argenteum) in Agrostis ...

Silvery Thread (Bryum argenteum) Moss Control
on Bentgrass Putting Greens with Carfentrazone
Fred H. Yelverton, Travis W. Gannon, and Leon S. Warren
North Carolina State University
Department of Crop Science

Moss Biology and Life History
Small, slow-growing perennial plants with
chlorophyll
Non-vascular plants – no vascular system
(conductive tissue)
No roots – have rhizoids to anchor plants (do
not absorb water or nutrients)

Moss Biology and Life History
Types of Mosses:
True mosses: Bryophytes, etc.
Peat mosses: absorb 20x their dry weight in
water
Granite mosses: found on mountains and
arctic

Moss Biology and Life History
Can remain viable after years of desiccation
(Richardson, 1982).
Reproduction:
sexual – capsules with spores that are often
propelled (like ferns)
asexual - fragmentation

Reasons for Increases in Moss Incidence:
Removal of mercury-based fungicides
(PMAS, Calaclor).
Low mowing heights
New formulations of fungicides,
insecticides, and herbicides

Research Trials
Research trials were initiated in western North
Carolina to evaluate carfentrazone for silvery
thread moss control on bentgrass putting greens
Evaluated various application rates, single versus
multiple applications, and applied alone or with nonionic
surfactant.

Moss Experimental Locations
• Black Mountain CC, Black Mt., N.C. (BM)
• Elk River CC, Banner Elk, N.C. (ER)
• Jefferson Landing GC, Jefferson, N.C. (JL)

Materials and Methods
• 4-0-0-18 Fe % (50 lb Fe/a) - Ironizer
• 1-0-0-4.5 Fe % (13.3 lb Fe/a) - Ironite
• Tee Time (45 lb Fe/a)
• Ultra Dawn (3.0 % v/v)

Materials and Methods-Test 1
• All previous treatments applied + oxadiazon
(1.5 lb ai/a)
• Oxadiazon (1.5 lb ai/a)
• Iron sulfate (36 lb Fe/a) + Ammonium Sulfate
(27 lb N/a)

• Treatments:
Materials and Methods
• Daconil ZN: 8.5 and 15.5 lb ai/a at 5 gal/M
• Daconil ZN: 8.5 and 15.5 lb ai/a at 10 gal/M
• Daconil W/S: 8.1 and 16.3 lb ai/a at 5 gal/M
• Daconil W/S: 8.1 and 16.3 lb ai/a at 10 gal/M

Daconil W/S 16.2 lbs
ai/a
Moss Control on Bentgrass Greens
ai/a
44 bc *
96 ab
LSD=11.77
10 WAIT
6 WAIT
53 ab
100 a
LSD=7.16
Daconil W/S 8.1 lbs
Daconil Zn 8.5 lbs
ai/a
Daconil Zn 15.5 lbs
ai/a
34 c *
43 bc *
94 ab
94 ab
0 20 40 60 80 100
Note: Similar results observed
with higher spray volume
% Control
Jefferson Landing:
Applied 2 times: 8-16
& 8-30-99, 5 gal
water/M

Quicksilver on Silvery
Thread Moss

% Control
100
80
60
40
20
Silvery Thread Moss Control (2 WAIT)
with Sequential Applications
0
15bc
30b 30b 33b
8bc
One App Two App Three App
Quicksilver 1 oz
Quicksilver 2 oz
Daconil WS 174 oz
Rates are per acre. Trial initiated 5-19. Sequential applications applied three weeks after previous application.
Quicksilver applied in 98 GPA while Daconil applied in 195 GPA.
13bc
31b

% Control
100
80
60
40
20
Silvery Thread Moss Control (4 WAIT)
with Sequential Applications
0
5b 3b
31a 35a
One App Two App Three App
0b
Quicksilver 1 oz
Quicksilver 2 oz
Daconil WS 174 oz
Rates are per acre. Trial initiated 5-19. Sequential applications applied three weeks after previous application.
Quicksilver applied in 98 GPA while Daconil applied in 195 GPA.
31a
38a

% Control
100
80
60
40
20
Silvery Thread Moss Control (8 WAIT)
with Sequential Applications
0
0b 0b 0b 0b 0b
13a 18a
One App Two App Three App
Quicksilver 1 oz
Quicksilver 2 oz
Daconil WS 174 oz
Rates are per acre. Trial initiated 5-19. Sequential applications applied three weeks after previous application.
Quicksilver applied in 98 GPA while Daconil applied in 195 GPA.

% Control
Silvery Thread Moss Control (2 WAIT)
with or without Non-ionic Surfactant
100
80
60
40
20
0
93a 94a
34b
Alone With NIS
Quicksilver 6 oz
Quicksilver 6 fb 6 oz
Daconil WS 174 oz
Rates are per acre. Trial initiated 7-12. NIS was X-77. Sequential applications applied two weeks after previous
application. Quicksilver applied in 98 GPA while Daconil applied in 195 GPA.
90a
73a

% Control
Silvery Thread Moss Control (4 WAIT)
with or without Non-ionic Surfactant
100
80
60
40
20
0
38cd
100a
38cd
Alone With NIS
Quicksilver 6 oz
Quicksilver 6 fb 6 oz
Daconil WS 174 oz
Rates are per acre. Trial initiated 7-12. Sequential applications applied two weeks after previous application.
Quicksilver applied in 98 GPA while Daconil applied in 195 GPA.
31cd
99a

% Control
Silvery Thread Moss Control (6 WAIT)
with or without Non-ionic Surfactant
100
80
60
40
20
0
50b
100a
75ab 75ab
95ab
Alone With NIS
Quicksilver 6 oz
Quicksilver 6 fb 6 oz
Daconil WS 174 oz
Rates are per acre. Trial initiated 7-12. Sequential applications applied two weeks after previous application.
Quicksilver applied in 98 GPA while Daconil applied in 195 GPA.

% Control
Silvery Thread Moss Control with Quicksilver T&O
100
80
60
40
20
0
and Daconil WeatherStik Applied Twice
21 20 34 LSD ( P = .05)
14-Aug 23-Aug 5-Sep
Jul 24 and Aug 6, 2003 application dates
Quicksilver T&O 0.67 oz/A
Quicksilver T&O 6.7 oz/A
Quicksilver T&O 13.4 oz/A
Quicksilver T&O 6.7 oz/A + NIS*
Daconil W.Stik 174 oz/A
Check
* NIS applied at 0.25% v/v

Additional Bentgrass Tolerance Trials
Regardless of paclobutrazol application
regime, ‘G2’ bentgrass exhibited significant
phytotoxicity.
Injury was greatest at 7 DAT and had subsided by
28 DAT.

Conclusions
Quicksilver provides a viable option for silvery
thread moss control on bentgrass putting
greens
Two applications (6.7 oz/a) are required for
acceptable silvery thread moss control.
Uncertainties remain about interactions with
Quicksilver and bensulide.