The Impact of Disease Suppressing and Plant Health Promoting Products on Creeping Bentgrass

Grown Under Shade Stress

Camden D. Shelton1, David S. McCall1, Kyle Miller2, and Dana Sullivan3

1Virginia Tech, Blacksburg VA; 2BASF Corp, Raleigh NC; 3TurfScout LLC, Greensboro NC

Literature Cited1. Sorochan, John. (2002) Sugar in Shade: The Effects of Exogenous Fructose

Applications to Turfgrass Under Reduced Light Conditions. Diss. Michigan State

University.

2. Madden, Lauren. Hughes, Garreth. Bosch, Frank.(2006) The Study of Plant

Disease Epidemics. American Phytopathological Society. St. Paul, MN. 64

3. Hsiang, Tom. Goodwin, P.H. Cortes-Barco, A.M. (2011) Plant Defense Activators

and Control of Turfgrass Diseases. Outlooks on Pest Management. Research

Information Corporation. University of Guelph.

Summary of Results

There were treatment differences in RVI, visual quality, and density

(Figure 3, 4, and 6).

Creeping bentgrass quality and density declined under high shade stress, and

was slow to recover as the season progressed.

Lexicon, Daconil Action and Heritage Action improved turf quality and increased

turf density compared to the untreated control in both years.

Foursome reduced visual turf quality, RVI and turf density on some collection

dates but the cumulative effect was comparable to the untreated in both years.

Chipco Signature had no impact on creeping bentgrass quality or density after

exposure to shade stress in either year.

Research Objective

Determine the impact that different plant health promoting products (PHPs) may

have on creeping bentgrass grown under high shade stress.

Materials and Methods• Location: ‘L-93’ creeping bentgrass, Glade Road Research Facility, Blacksburg,

Virginia.

• Years: Summer 2015 and 2016.

• Experimental Design: Randomized complete block design, two trials, four

replications, 2.2 m2 plot size.

• Treatments: All treatments applied on a 21 day interval.

• Plot Maintenance: Chipco 26GT (3.05 kg iprodione ha-1) and Secure (1.75 kg

fluazinam ha-1 ) were applied on a two week rotation throughout the duration of

the trial to prevent dollar spot and brown patch from impacting treatment

responses.

• Data Analysis: Spectral reflectance and visual estimations of turf quality,

density, and color were assessed bi-weekly in 2015 and weekly in 2016

throughout the duration of the study. Data were transformed to AUPC and

subjected to ANOVA (P=0.05) and means separated using Fisher’s protected

LSD, when appropriate

Significance to the Turf IndustryPlant health promoting products tested in this study had varying impacts on creeping

bentgrass grown under shade stress. Lexicon, Daconil Action, and Heritage Action

improved turf quality beyond traditional disease suppression. These products are

fungicides labeled to control turf diseases but this research proves an added benefit

of improved shade tolerance. Foursome and other pigmented products (data not

shown) decreased turf density under shaded conditions and should be avoided

when light quality is low.

Figure 2. Ratio vegetation index (RVI=760nm/ 670nm) geo-referenced reflectance

map using cart-mounted ACS470 (Holland Scientific). Highlighted plots represent:

Untreated control (red), Lexicon 1.3 L ha-1 (black), Foursome 1.1 L ha-1 (blue).

Overview There are many products on the market that go beyond fungicidal properties or

nutritional value but their role in plant protection is not well understood

Plant defenses are activated prior to the onset of various environmental and

biological stressors (Hsiang, 2011)

Shade stress reduces photosynthesis, in turn depleting carbohydrate reserves

(Sorochan, 2002)

Low red light leads to more shoot growth while decreasing root growth

(Sorochan 2002)

Research is needed to address how plant-activating products impact creeping

bentgrass (Agrostis stolonifera) tolerance to shade stress

Figure 3. Standardized area under the progress curve (AUQPC) of turf quality

objectively quantified using the ratio vegetation index (RVI) across 2015 and 2016

trials. Mean separation analyzed by year where ‘A=A, 2016’ and ‘a=a, 2015’.

Figure 4. Visual turf quality (1-9 scale, 9 = highest quality and 6 = minimally

acceptable) assessed throughout Summer 2016.

Figure 6. Standardized AUPC of visual turf density in plots treated with different

PHPs, using 1-9 scale (9 = highest density) during the Summer 2015 and 2016.

Mean separation analyzed by year where ‘A=A, 2016’ and ‘a=a, 2015’.

Figure 1.Shade structure composed of Gemplers 60% black woven shade cloth

(Ariens Specialty Brands LLC). Photosynthetically active radiation (PAR) average

under shade structure equal to 357 µmol m2 s-1.

Figure 5. Turf quality as affected by treatment under shade stress on August 5, 2016.

This image taken three weeks after the third application.

0

1

2

3

4

5

6

7

8

9

UntreatedControl

Lexicon(1.1 L ha-1)

Lexicon(1.3 L ha-1)

ChipcoSignature (12

kg ha-1)

Daconil Action(11.14 L ha-1)

Heritage Action(1.22 kg ha-1)

Foursome(1.27 L ha-1)

RV

I AV

G

2016 2015

CD

b

A

a

A

a CD

b

AB

ab

AB

a CD

b

Heritage Action (1.22 kg ha-1) Foursome (1.27 L ha-1)

Lexicon (1.1 kg ha-1)Chipco Signature (12 kg ha-1) Untreated Control

July 11, 2016 (3 weeks after second app) August 12, 2016 (1 week after fourth app)

0

1

2

3

4

5

6

7

8

9

UntreatedControl

Lexicon(1.1 L ha-1)

Lexicon(1.3 L ha-1)

ChipcoSignature (12 kg

ha-1)

Daconil Action(11.14 kg ha-1)

Heritage Action(1.22 kg ha-1)

Foursome(1.27 L ha-1)

TUR

F D

ENSI

TY (

1-9

)

2016 2015

C

b

A

a

A

a

BC

bAB

aA

a

C

b

Treatment Active Ingredient Rate

Lexicon fluxapyroxad + pyraclostrobin 0.18 + 0.36 kg ai ha-1

Lexicon fluxapyroxad + pyraclostrobin 0.25 + 0.50 kg ai ha-1

Chipco Signature aluminum tris 9.74 kg ai ha-1

Daconil Action chlorothalonil + acibenzolar-s-methyl 8.12 + 0.016 kg ai ha-1

Heritage Action azoxystrobin + acibenzolar-s-methyl 0.61 + 0.014 kg ai ha-1

Foursome C32H18N8 (proprietary pigment) 3.60 L ha-1

3

4

5

6

7

8

9

15-Jun 22-Jun 29-Jun 6-Jul 13-Jul 20-Jul 27-Jul 3-Aug 10-Aug 17-Aug

VIS

UA

L Q

UA

LITY

Untreated Control 5.4 b Lexicon (1.1 L ha-1) 6.6 a Lexicon (1.3 L ha-1) 6.7 a

Chipco Signature (12.05 kg ha-1) 5.6 b Daconil Action (11.14 L ha-1) 6.4 a Heritage Action (1.22 kg ha-1) 7.0 a

Foursome (1.27 L ha-1) 5.0 b

* LSD= 0.613 * LSD= 1.168 * LSD= 1.193 * LSD= 1.132 * LSD= 1.344

* Indicates significant treatment differences (P=0.05)

Shade cloth installed 6/6 and

removed 6/22 for recoveryReinstalled on 6/29 and

removed again on 8/1

101

201

301

401

101

201

301

401