Phytotoxicity and Efficacy of Fascination (6-Benzyl Adenine + Gibberellic Acid)

for Enhanced Branching of Phlox (Phlox divaricata ssp. laphamii)

By

Heiner Lieth, Director

Linda Dodge Shannon Still Lea Ragaini Ron Lane

Jackie Fortunko

Project: Interregional Research Project #4 Project Number 23194A - July 29, 2004

Acknowledgements: Ahmet Gulcu Donors/Supporters: CDFA Minor Crops Research Grant, Project 2: Enhancement of the Western

Region IR-4 Program to Address California Needs Green Leaf Perennials, Lancaster, PA

UC Davis Environmental Horticulture IR4 Center Department of Environmental Horticulture University of California One Shields Ave. Davis, CA 95616 http://envhort.ucdavis.edu/ir4

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IR-4 ORNAMENTAL DATA REPORTING FORM (Please type or print) 1. INVESTIGATOR (Name, Address, Phone#):

Dr. Heiner Lieth Department of Environmental Horticulture University of California One Shields Ave. Davis, CA 95616 Ph 530-752-7198 FAX 530-752-1819 Email: jhlieth@ucdavis.edu

LOCATION OF TRIAL: TRIAL TYPE:(check one) FIELD CONTAINER X GREENHOUSE INTERIORSCAPE

2. PESTICIDE:

COMMON NAME: 6-Benzyl Adenine + Gibberellic Acid A4 A7 FORMULATION: 1.8% + 1.8% (w/w)

BATCH NO.: PRODUCT: Fascination EPA REG. NO. 27135 MFG: Valent

3. USE INFORMATION: COMMON NAME SCIENTIFIC NAME

PLANT: Phlox Phlox divaricata ssp. laphamii REASON: enhanced branching of potted crops SOIL TYPE OR TYPE OF POTTING MIX: UC Mix

% SAND 35 % SILT % CLAY % OM 65 % pH 6.5 SEEDING DATE EMERGENCE DATE TRANSPLANTING DATE 4/18/04 PLANT OR POT SPACING 6” ROW SPACING 6” POT SIZE 4-inch PLOT SIZE 50 sq. ft. EXPERIMENTAL DESIGN randomized complete block NO.OF REPS 9

(3 blocks) 4. APPLICATION PARAMETERS:

TYPE OF APPLICATION: foliar NO. OF APPLICATIONS 2 APPLICATION TYPE manual spray bottle

NOZZLE TYPE/SIZE NOZZLE PRESSURE DELIVERY RATE CALIBRATION DATE(S)

5. APPLICATION SUMMARY:

APPL.DATE

RATES (ppm)*

GROWTH STAGE

6/17/04

0, 125 (0.5X), 250 (1X), 500 (2X)

8 weeks post-transplant

7/08/04

0, 125 (0.5X), 250 (1X), 500 (2X)

11 weeks post-transplant

*Be sure to provide units

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IR-4 ORNAMENTAL DATA REPORTING FORM (Please type or print) 6. RAINFALL/IRRIGATION RECORDS:

INCLUDE RAINFALL/IRRIGATION INFORMATION (printouts, IR-4 forms, etc.) Plants were watered as needed (at least once daily) with half-strength Hoagland’s solution

7. OTHER PESTICIDES, FERTILIZER, LIME AND ADJUVANTS USED:

PRODUCT Orthene + Sanmite AMOUNT DATE 6/23/04 PRODUCT Orthene + Heritage AMOUNT DATE 6/30/04 PRODUCT Talstar F AMOUNT DATE 7/08/04 PRODUCT Pylon AMOUNT DATE 7/21/04

8. NARRATIVE SUMMARY OF METHODS AND RESULTS: (Use more pages if needed) Materials and Methods Plant Material and Culture. Young plants of Phlox divaricata ssp. laphamii were received from Yoder Bros. on 4/12/04. These were transplanted to 4-inch pots containing UC Mix on 4/18/04 and maintained in a greenhouse under natural day length for 8 weeks until the experiment began on June 17, 2004. For the experiment, the plants were transferred to a greenhouse under natural day length with day/night temperatures of 82°F/65°F (28°C/18°C) (Figure 1). The plants were watered as needed (at least once daily) during the 6-week experiment with half-strength Hoagland’s solution. Applications of pesticides as part of a normal pest management program were made as needed (see No. 7 above). Experimental Procedure. Thirty-six plants were randomly chosen and individually tagged for treatment with 0, 125 ppm (0.5X), 250 ppm (1X) or 500 ppm (2X) Fascination with 9 replicates per treatment. These dosages were prescribed in an IR4 Fascination protocol dated 6/04 (Appendix A). The plants received the first of two foliar spray applications of the designated treatments on June 17, 2004 using manual spray bottles to spray leaves to runoff. The second application was made 21 days later on July 8, 2004. The plants were arranged in a randomized complete block design with 3 blocks and 3 treatment replicates per block. Phytotoxicity and efficacy measurements were taken at day 0 (June 17, 2004), day 21 (July 8, 2004) and day 42 (July 29, 2004). Phytotoxicity evaluations were based on a numerical rating scale of 0 (no injury) to 10 (complete kill) (Table 1). Efficacy measurements consisted of overall plant height (cm) and width (cm). In addition, the number of secondary branches on one tagged branch per plant was counted. Statistical Analysis. The data were analyzed using Proc GLM of the Statistical Analysis System (SAS). Phytotoxicity and change in mean value from the starting stem length, starting plant width, and number of shoots per branch were analyzed for significant differences using t-tests. Data were also analyzed by grouping control and 125 ppm (“low”) and 250 and 500 ppm (“high”) for comparison with the same statistical procedures. Results Phytotoxicity. Fascination at an application rate of 500 ppm had a higher phytotoxicity index for Phlox divaricata ssp. laphamii at 3 weeks than all other treatments and control (Figure, Appendix B). At 6 weeks, all Fascination rates had a higher phytotoxicity index than the control. When comparing “high” against “low” we find that the “high” treatments had significantly higher phytotoxicity index values than the “low” treatments at both 3 and 6 weeks (Figure 2, Appendix B). Plant damage symptoms exhibited by Phlox included chlorosis of newer leaves and necrosis of older leaves (Figure 2a).

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Efficacy. Phlox plants treated with 500 ppm Fascination gained more in height at 3 weeks than those treated with 250 ppm or the control plants (Figures 3 and 3a, Table 2). Plants treated with 125 ppm Fascination gained more in height at 3 weeks than the control plants. Phlox plants treated with 500 ppm Fascination gained more in height at 6 weeks than those in all the other treatments. Those plants treated with 125 ppm or 250 ppm gained more in height at 6 weeks that the control plants. Phlox plants treated with 500 ppm Fascination increased in plant width significantly more than control plants at 3 weeks (Figure 4, Table 2). At 6 weeks, P. divaricata ssp. laphamii plants treated with 500 ppm Fascination showed greater increase in plant width than those in all other treatments. Plants treated with 125 or 250 ppm Fascination increased more in plant width than those in the control group at 6 weeks. Considerable variation in secondary branch counts prevented any conclusions about the effect of Fascination by week 3. By week 6, some significant differences were found at the 90% confidence level. In particular, the secondary branch count in the control was less than that of the 1X treatment. When comparing “low” and “high” treatment groups, we found that there was a significant difference at week 6 with “low” averaging 1.9 secondary branches and the “high” treatment averaging 4.6 (Figure 5). Discussion Phytotoxicity. Fascination caused minor phytotoxicity on Phlox divaricata ssp. laphamii with higher index values at 3 weeks than at 6 weeks. This suggests that the plants grew out of the effect. Efficacy. Fascination at all rates increased the height and width of Phlox divaricata ssp. laphamii after 6 weeks. This product is effective for increasing the height, width and secondary branch counts of Phlox divaricata ssp. laphamii at the proposed 1X rate as well as the higher 2X rate. It lacks efficacy at the 0.5X rate. Unfortunately, we found that at the efficacious rates, the plants did suffer some leaf-tip burn and slight chlorosis.

9. GOOD RESEARCH PRACTICE STATEMENT:

I acknowledge that I have read and followed the IR-4 Research protocol and completed this trial following good agricultural practice, or reported any deviations (note any changes from authorized protocol in narrative).

SIGNATURE DATE PRINCIPAL INVESTIGATOR

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Table 1. Numerical plant damage rating scale used for phytotoxicity determinations.

Rating Description of plant damage 0 No damage 1 No visible damage but unintended (non-permanent) impact 2 Slight leaf/tissue damage or chlorosis (curling leaves, necrosis, etc.) 3 Marginal chlorosis on some leaves; large yellow spots, some tip burn (damage

on up to 10% of plant) 4 10% – 20% of plant damaged 5 Significant damage to much of plant (30% - 40%) 6 40% – 60% of plant damaged 7 Chlorosis or necrosis on most of plant (60% - 70%) 8 Abscised leaves, branch dieback 9 Tissue severely damaged (80% - 100% of plant) 10 Complete kill

Air Temperature - Greenhouse 180

505560657075808590

6/12/2

004

6/19/2

004

6/26/2

004

7/3/20

04

7/10/2

004

7/17/2

004

7/24/2

004

7/31/2

004

Tem

pera

ture

(F)

Figure 1. Greenhouse temperatures during the experiment to evaluate the effects of Fascination on Phlox divaricata ssp. laphamii.

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0123456789

10

0123456789

10

0 3 6Duration of experiment (weeks)

0 3 6

LowHigh

Control125 ppm (0.5 X)250 ppm (1 X)500 ppm (2 X)

Phy

toto

xici

ty in

dex

Figure 2. Top graph: Phytotoxicity Index for Phlox divaricata ssp. laphamii treated with 0, 125, 250 or 500 ppm Fascination. SE bars shown. n=9. See Table 1 for explanation of values. Bottom graph: Phytotoxicity Index for the “low (control and 125 ppm, n=18) and “high” (250 ppm and 500 ppm, n=18) treatment groups.

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Figure 2a. Typical plant damage symptoms of necrotic older leaves seen on Phlox divaricata ssp. laphamii treated with 0, 125, 250 or 500 ppm Fascination.

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0

10

20

30

40

Pla

nt h

eigh

t (cm

)

0 3 6Duration of experiment (weeks)

Control125 ppm (0.5X)250 ppm (1X)500 ppm (2X)

Figure 3. Plant height of Phlox divaricata ssp. laphamii treated with 0, 125, 250 or 500 ppm Fascination. SE bars shown. n=9.

Table 2. Average increase (cm) of height and width for plants in the control and Fascination treatments for Phlox divaricata ssp. laphanii. Different letters within a column indicate significant differences between different treatments (P < 0.05). Means ± SE (n=9).

Height increase (cm) Width increase (cm) over 3 weeks over 6 weeks over 3 weeks over 6 weeks Control 0.89 ± 1.20 c 3.89 ± 0.75 c 4.11 ± 1.38 b 12.33 ± 1.08 c 125 ppm 4.89 ± 0.85 ab 10.67 ± 1.06 b 11.22 ± 1.95 a 19.11 ± 1.16 b 250 ppm 6.44 ± 1.62 bc 11.33 ± 1.21 b 9.11 ± 2.03 ab 20.22 ± 1.74 b 500 ppm 9.78 ± 2.04 a 15.44 ± 1.64 a 14.00 ± 2.86 a 26.89 ± 1.79 a

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Block A

Block B

Block C Figure 3a. Phlox divaricata ssp. laphamii plants 6 weeks after 2 foliar applications of 0, 125, 250 or 500 ppm Fascination (Week 0 and Week 3).

Control 125 ppm 250 ppm 500 ppm

Control 125 ppm 250 ppm 500 ppm

Control 125 ppm 250 ppm 500 ppm

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0

10

20

30

40

50

60

Pla

nt w

idth

(cm

)

0 3 6Duration of experiment (weeks)

Control125 ppm (0.5X)250 ppm (1X)500 ppm (2X)

Figure 4. Plant width of Phlox divaricata ssp. laphamii treated with 0, 125, 250 or 500 ppm Fascination. SE bars shown. n=9.

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0

2

4

6

0

2

4

6

8

0 3 6Duration of experiment (weeks)

0 3 6

LowHigh

Control125 ppm (0.5 X)250 ppm (1 X)500 ppm (2 X)

Sec

onda

ry b

ranc

hes

Figure 5. Number of secondary branches per branch for Phlox divaricata ssp. laphamii treated with 0, 125, 250 or 500 ppm Fascination. The top graph shows means and standard errors (n=9) for each treatment while the bottom graph shows means and standard errors (n=18) for data pooled as “low” (control and 125 ppm) and “high” (250 and 500 ppm) treatments.

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Appendix A: GROWTH ENHANCEMENT OF ORNAMENTAL PLANTS WITH FOLIAR APPLICATIONS OF 6-BENZYL ADENINE + GIBBERELLIC ACID (FASCINATION) Date: 6/04 Ornamental Protocol Number: 670 General label directions: Refer to product label or Technical Bulletin. Research program: Pest(s)/Plants – Plants other than labeled species. Pesticide (common name and trade name): Refer to treatment list shown below. For label, material & if needed, spray surfactant contact: Valent USA, Joe Chamberlin, 770-985-0303, jcham@valent.com

Plot size (must be adequate to reflect actual use condition) Replicates Minimum of 4 Treatment Units Controls (untreated controls to be included in all experiments)

Application: FASCINATION Dosages - 1/2x 125 ppm or 0.125 pt/5 gal.

1x 250 ppm or 0.25 pt/5 gal. 2x 500 ppm or 0.5 pt/5 gal.

Active Ingredient: 6-benzyl adenine + gibberellic acid (FASCINATION). Volume - Minimum of 100 gal/A. Timing - 2 Applications, 21 day spray interval. Record number of branches and length, then increased branching, increased extension and crop safety at 7, 14, 21 (then 2

nd appl.), 28 and 42 DAT.

Reports: Method of application: Treatments should be applied according to product label instructions. application equipment consistent with

conventional commercial equipment. Report completely on experimental design and method of application. Report plant size height x width before treatment and throughout the experiment.

Weather – Maintain temperature and precipitation (including irrigation) data. Soil type – Identify soil type used in experimental area. Product – When submitting data, include EPA registration number of product used. Efficacy – Data should include percent control as well as an indication that infestation was light, heavy, etc. Record all application and evaluation dates. Phytotoxicity – Record phytotoxicity data at all rates. Use a 0-10 scale. 0 = No Phytotoxicity 10 = complete kill. Please direct questions to: Dr. Robert M. Herrick, IR-4 Project, 681 US Highway #1 South, North Brunswick, NJ Phone: (732) 932-9575, Ext. 629.

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Appendix B: PHYTOTOXICITY REPORT FORM Phlox Data Phyto Phyto Phyto

Rate Rate Rate Fascination Treatment Block Rep 6/17/04 7/8/04 7/29/04

Control A 1 0 2 1 Control A 2 1 3 2 Control A 3 1 2 3 Control B 1 2 3 0 Control B 2 1 3 1 Control B 3 2 2 2 Control C 1 2 3 1 Control C 2 3 4 1 Control C 3 2 3 2 Control Mean 1.56 2.78 1.44 Control Std Dev 0.88 0.67 0.88

125 ppm A 1 1 2 2 125 ppm A 2 2 3 2 125 ppm A 3 1 3 3 125 ppm B 1 2 3 2 125 ppm B 2 1 3 2 125 ppm B 3 1 2 2 125 ppm C 1 2 3 2 125 ppm C 2 1 2 3 125 ppm C 3 2 3 2 125 ppm Mean 1.44 2.67 2.22 125 ppm Std Dev 0.53 0.50 0.44

250 ppm A 1 2 3 3 250 ppm A 2 2 3 3 250 ppm A 3 3 3 2 250 ppm B 1 3 3 2 250 ppm B 2 2 2 2 250 ppm B 3 1 2 1 250 ppm C 1 2 3 3 250 ppm C 2 2 3 3 250 ppm C 3 2 3 3 250 ppm Mean 2.11 2.78 2.44 250 ppm Std Dev 0.60 0.44 0.73

500 ppm A 1 2 4 3 500 ppm A 2 2 3 2 500 ppm A 3 2 4 3 500 ppm B 1 1 3 2 500 ppm B 2 2 4 1 500 ppm B 3 1 3 2 500 ppm C 1 2 4 3 500 ppm C 2 2 4 2 500 ppm C 3 2 3 3 500 ppm Mean 1.78 3.56 2.33 500 ppm Std Dev 0.44 0.53 0.71

NOTE: DEFINE MEASUREMENT OF PHYTOTOXICITY, OR INDEX OF INJURY (0=NO INJURY, 10=COMPLETE KILL) (See Table 1)

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Appendix C: EFFICACY REPORT FORM Phlox Data Plant Plant Plant Plant Plant Plant

Height Height Height Width Width Width # Branches # Branches # Branches Fascination (cm) (cm) (cm) (cm) (cm) (cm) Treatment Block Rep 6/17/2004 7/8/2004 7/29/2004 6/17/2004 7/8/2004 7/29/2004 6/17/2004 7/8/2004 7/29/2004

Control A 1 15 19 19.5 35 35.75 42 0 0 0 Control A 2 16 22 21 28.5 38.25 44.25 0 0 1 Control A 3 14 19.5 15.5 37.25 44 42.75 0 1 1 Control B 1 18 20 18 30.75 33.25 50.5 0 0 0 Control B 2 15 15.5 20.5 31 30.75 43.25 0 0 0 Control B 3 15.5 12.5 22.5 19.5 29.5 43.25 0 0 1 Control C 1 15.5 16.5 22 30 36 45.25 0 0 0 Control C 2 18 11 20.5 30.25 33.75 39.25 3 2 3 Control C 3 16.5 14.5 18 37.75 36.25 42 0 0 0 Control Mean 15.94 16.72 19.72 31.11 35.28 43.61 0.33 0.33 0.67 Control Std Dev 1.36 3.68 2.22 5.48 4.29 3.08 1.00 0.71 1.00

125 ppm A 1 18.5 20.5 21 23 32.25 49.25 0 0 5 125 ppm A 2 18 17 22.5 35 37.75 42.75 0 0 0 125 ppm A 3 15 23 28.5 36.75 43.75 54 0 0 0 125 ppm B 1 16 23.5 24.5 30.25 39.75 47.75 0 0 7 125 ppm B 2 16 23.5 30.5 26.5 43.5 45.75 0 2 5 125 ppm B 3 15 22.5 28 35.25 51 53.75 0 1 6 125 ppm C 1 16.5 21 28 26.5 40 47.5 0 0 4 125 ppm C 2 14.5 25 28.5 26.75 44.5 47.75 0 0 1 125 ppm C 3 14 25 27 25.5 34 48.75 0 2 3 125 ppm Mean 15.94 22.33 26.50 29.50 40.72 48.58 0.00 0.56 3.44 125 ppm Std Dev 1.53 2.52 3.14 5.00 5.75 3.56 0.00 0.88 2.60

250 ppm A 1 25 28 34.5 40 42.5 56.5 0 0 5 250 ppm A 2 8 11 24.5 27.25 30.5 40.5 0 6 10 250 ppm A 3 16 20 21.5 34 34 55 0 3 4 250 ppm B 1 15 24 28.5 35.5 46.75 53 0 10 10 250 ppm B 2 20 22 29 34 43 60.25 0 0 4 250 ppm B 3 18.5 20 29.5 34.25 51 51.5 0 0 0 250 ppm C 1 14.5 21 28.5 27 43.25 52 0 0 14 250 ppm C 2 17 24 29 28 43.5 54.25 0 0 1 250 ppm C 3 16.5 26 25.5 35.75 42 54.25 0 0 0 250 ppm Mean 16.72 21.78 27.83 32.86 41.83 53.03 0.00 2.11 5.33 250 ppm Std Dev 4.57 4.87 3.67 4.48 6.17 5.38 0.00 3.62 4.97

500 ppm A 1 17.5 29.5 37.5 37.25 40.5 61 2 1 0 500 ppm A 2 15 33 40 23 50 50.5 0 4 7 500 ppm A 3 16 27 32.5 36 40.5 60.25 0 1 4 500 ppm B 1 15.5 21.5 30 33.75 37.75 64.5 0 0 11 500 ppm B 2 10.5 22.5 30.5 22.25 33.25 48 0 0 1 500 ppm B 3 19 17 27 27.75 34.25 53.75 0 0 14 500 ppm C 1 15.5 22 25 34 48.25 57.5 0 0 0 500 ppm C 2 20 35 32 30 59.75 57.5 0 0 0 500 ppm C 3 21.5 31.5 36 21.75 47 53.25 0 0 0 500 ppm Mean 16.72 26.56 32.28 29.53 43.47 56.25 0.22 0.67 4.11 500 ppm Std Dev 3.25 6.13 4.87 6.11 8.54 5.32 0.67 1.32 5.37