Sustainable Management of Phytophthora Cinnamomi and Ambrosia Beetles Under Stress Conditions

Progress report for GS20-228

Project Type: Graduate Student
Funds awarded in 2020: $16,335.00
Projected End Date: 08/31/2022
Grant Recipient: Tennessee State University
Region: Southern
State: Tennessee
Graduate Student:
Major Professor:
Dr. Fulya Baysal-Gurel
Tennessee State University
Expand All

Project Information

Summary:

Phytophthora root rot causes major economic losses in woody ornamental nurseries, especially in plants exposed to flooding. Ambrosia beetles, which attack stressed trees, are also important pests of woody plants. Effective Phytophthora fungicides, biofungicides are needed due to the increased risk of infestation and spread during flooding. Since ambrosia beetles also are associated with flooded woody ornamentals, understanding effect of alternative strategies such as fungicide, kaolin, charcoal, verbenone, etc. on these secondary pests are important. The specific objectives include evaluation preventive and curative applications of fungicides for control of P. cinnamomi and ambrosia beetles on containerized flowering dogwoods exposed to a simulated root flooding events of 1, 3, or 7 days and integration of alternative strategies (fungicide, kaolin, charcoal, verbenone, etc.) to optimize Phytophthora cinnamomi and ambrosia beetle management on woody ornamentals exposed to simulated flood events.

Project Objectives:

The specific objectives include evaluation preventive and curative applications of fungicides for control of P. cinnamomi and ambrosia beetles on containerized flowering dogwoods exposed to a simulated root flooding events of 1, 3, or 7 days and integration of alternative strategies (fungicide, kaolin, charcoal, verbenone, etc.) to optimize Phytophthora cinnamomi and ambrosia beetle management on woody ornamentals exposed to simulated flood events.

Objective 1- Management of Phytophthora cinnamomi during simulated root flooding events using fungicides and biofungicides

 The purpose of this objective is to evaluate fungicides, biofungicides, or host plant defense inducers for preventive and curative control of P. cinnamomi on flowering dogwood seedlings (Cornus florida L.) exposed to a simulated root flooding event of 1, 3, or 7 days.

Objective 2- Integration of sustainable alternative strategies to optimize Phytophthora cinnamomi and ambrosia beetle management

The purpose of this objective is to optimize management of Phytophthora root rot and ambrosia beetles by using alternative strategies such as fungicide/biofungicide (selected from Objective 1), kaolin, charcoal, verbenone, etc. 

Research

Materials and methods:

Objective 1: Management of Phytophthora cinnamomi during simulated root flooding events using fungicides and biofungicides

The first trial of the study was conducted in a greenhouse setting at the Tennessee State University Otis L. Floyd Nursery Research Center in McMinnville, TN. One year old stratified seeds of dogwood Cornus florida L. ‘Chrerokee Princess’ were seeded in Morton’s Grow Mix #2 (Canadian sphagnum peat [60%], vermiculite [20%], and perlite [20%], average substrate bulk density 144 kg/m3: Morton’s Horticultural Products, McMinnville, TN). After a month, the seedlings were transplanted to 10.2 cm pots containing potting substrate (Morton’s Nursery Mix: Processed Pine Bark [55%-65%], Canadian Sphagnum peat and Sand : Morton’s Horticultural Products, McMinnville, TN). A month after transplantation, the seedlings were arranged in a completely randomized block design and treatments were drench applied. Six replications per treatment were used with two controls: non-treated inoculated control (positive control) and non-treated non-inoculated control (negative control).

Preventative Treatment: Treatments were applied in two different timings: 3 weeks before flooding and 1 week before flooding. A list of the treatments is given in Table 1. Seedlings were inoculated three days before flooding using rice grain inoculum of P. cinnamomi. Two rice grains per pot were buried on opposite sides of the plant, 5 cm below the surface of potting substrate. Three days after the inoculation, the seedlings were flooded with the help of Zip-Top bags to prevent water loss. The water was drained after 1, 3 and 7 days. After draining the water, the seedlings were irrigated regularly for 2 minutes daily using over-head irrigation. Fifteen days after draining water, the study was terminated. Growth data parameters were recorded during the initial and final stages of the study. The root systems were assessed for root rot severity using visual observation ranking disease on a scale of 0-100%. The recovery percentage of the pathogen was also recorded by plating the root samples (~ 1 cm) from each plant (5 cuttings per plant). PARPH-V8 was prepared by centrifuging the mixture of 0.5 g CaCO3 (98% Acros Organics, Geel, Belgium), 50 ml V8 juice (Campbell, Camden, NJ) for 10 min at 8,000 rpm. 450 ml of deionized water was added to the buffered and clarified V8 juice with 7.5 g of agar (Sigma-Aldrich, St. Louis, MO) and autoclaved for 15 min. After autoclaving, 500 µL of the fungicide and antibiotics [pentachloronitrobenzene (PCNB) (99% (GC) Sigma-Aldrich, St. Louis, MO) (0.63 g/50 ml ethanol), ampicillin (Sigma-Aldrich, St. Louis, MO) (1.25 g/50 ml ethanol), rifampicin (Sigma-Aldrich, St. Louis, MO) (0.05 g/50 ml ethanol), pimaricin (2.5%) (MP Biomedicals, Santa Ana, CA), and hymexazol (Sigma-Aldrich, St. Louis, MO) (250 mg/50 ml sterilized water)] were added to the medium  to make Phytophthora selective media.

Curative Treatment: All of the seedlings were flooded on the same day. Three days before flooding, seedlings were inoculated using rice grain inoculum similar to the preventative application. After the flooding, water was drained out in 1, 3 and 7 days, respectively. Treatments were applied 24 hr. after the water was drained as a drench application. All treatments in Table 1 were applied except Actigard, MBI110, ON Gard and RootShied Plus. All treatments were applied more than twice except Subdue MAXX. The curative treatment study was terminated 15 days after the last application of Subdue MAXX, following the 10-week application interval. Data recording parameters were similar to those used in the preventative treatment study. Evaluation of root rot severity and percent recovery of P. cinnamomi were carried out in the same way as the preventative treatment.

Statistical Analysis: Statistical analysis was performed using SAS statistical software. All recorded data were analyzed using one-way Analysis of Variance (ANOVA). Means were separated using Fisher’s Least Significant Difference (LSD) test in Generalized Linear Model (GLM).

Objective 2: Integration of sustainable alternative strategies to optimize Phytophthora cinnamomi and ambrosia beetle management

This study was conducted at the outdoor setting of Otis L.Floyd Nursery Research Center in McMinnville, TN next to a wooded area to observe the effects of ambrosia beetles. Commercially available dogwood trees (Cornus florida L.) were used in this study. Four products, Subdue MAXX, Permethrin, Charcoal and Kaolin, were used for seven different treatments. Non-treated, inoculated plants and non-treated, non-inoculated plants were considered as controls. The list of the treatments and their application rate is given in Table 11. The dogwood trees were sorted according to their diameter and measured with a caliper reading. Trees with more than 14 cm diameter were used. After sorting, they were arranged in a completely randomized block design with six replications for each treatment. Subdue MAXX was drench applied 21 days before pathogen inoculation. P. cinnamomi was used to inoculate as a rice grain inoculum, with four rice grains per container. One day after inoculation, Permethrin was sprayed over the trunks of the trees. Three days after inoculation, the trees were flooded using the polythene bags to ensure water stayed in the container. Two days after flooding, Charcoal + Kaolin was sprayed over the trunks of the trees. The study was terminated after 21 days of flooding. All treatments had both inoculated and non-inoculated trees with six replications of each treatment.

Plant growth data were recorded during the start and end of the study. Ambrosia beetle attacks were recorded every other day using different color wax pencils. Root systems were assessed at the end of the study to record root rot using visual observation on a scale of 0-100%. Percent recovery of the pathogen was recorded by placing the root subsample (~1 cm) in PARPH-V8 media (10 roots per plant). The data on pathogen recovery were recorded after a week of root plating. The procedure for making PARPH-V8 is similar to objective 1.

Statistical Analysis: Statistical analysis was done using SAS statistical software. Plant growth data, disease severity and percent recovery of the pathogen were analyzed using one-way Analysis of Variance (ANOVA) in Generalized Linear Model (GLM), whereas ambrosia beetle attacks were analyzed using Genmod.

Research results and discussion:

Objective 1:

Preventative Treatments: In the preventative study, one week before flooding, all treatments were able to significantly suppress the disease severity compared to the inoculated control in one day flooding (Table 2). Alliete, Empress Intrinsic, Segovis, Subdue MAXX and Interface had lower Phytophthora root rot as compared to the positive control and was comparable with the negative control. In one day of flooding, no significant differences were found in plant width increase among the treatments. However, Signature Xtra had the highest plant height increase and total plant weight. Along with Signature Xtra, Aliette and Interface had the highest total plant weight. Additionally, Interface also had highest root weight among the treatments.

Within three days of flooding, all treatments significantly suppressed P. cinnamomi as compared to the positive control (Table 3). Alliete had the greatest height increase, and Actiguard and RootShield Plus had the greatest average width increase. Similarly, Signature Xtra had the greatest root and total weight among the treatments. Within seven days of flooding, all treatments except Interface significantly reduced the pathogen compared to the positive control (Table 4). No significant differences were observed in plant height increase and average width increase among the treatments. Alliete, RootShield Plus and Signature Xtra had the greatest total weight and root weight among the treatments.

In the preventative study, three weeks before flooding, all treatments except MBI110 significantly suppressed disease compared to the positive control (Table 5). Signature Xtra had the greatest plant height increase and ON Gard had the greatest average plant width, root weight and total weight increase. Along with ON Gard, Signature Xtra and Interface had higher root weight among the fungicidal treatments in one day of flooding. Within three days of flooding, all treatments except MBI110 and Interface significantly suppressed the disease severity as compared to the positive control (Table 6). Signature Xtra had the greatest plant height increase and Alliete, MBI110, Subdue MAXX, Signature Xtra and Tartan had greatest average plant width increases among the fungicidal treatments. Similarly, Signature Xtra had the greatest plant total weight and root weight increase among the treatments. Within seven days of flooding, all treatments except MBI110 and Interface had significantly suppressed the disease severity compared to the positive control (Table 7). ON Gard had the highest plant height increase, total weight and root weight among the treatments. Alliete and ON Gard had the highest average plant width increases among the treatments. No phytotoxicity was observed during the study.

Curative treatments: Within one day of flooding, all treatments significantly suppressed Phytophthora root rot compared to the positive control (Table 8). Interface had the greatest plant height increase, average width increase, plant total weight and root weight increase among the treatments. Within three days of flooding, all treatments significantly suppressed the disease severity compared to the inoculated control (Table 9). Similar to one day of flooding, Interface had the greatest plant height increase, average width increase, plant total weight and root weight among the treatments. Within seven days of flooding, all treatments significantly suppressed the disease severity compared to the positive control but none of them were statistically similar to the negative control (Table 10). Pageant had the greatest plant height increase, average plant width increase, total plant weight and root weight among the treatments. No phytotoxicity was observed during the study.

 

Objective 2:

Among the treatments, inoculated non-treated (positive) control had the highest disease severity whereas non-inoculated non-treated (negative) control had the lowest disease severity (Table 11). All non-inoculated treatments except Charcoal +Kaolin significantly suppressed the disease severity compared to the positive control and were not statistically different from the negative control. Combination of Subdue MAXX and Permethrin was the only treatment to significantly suppress the phytophthora root rot among the inoculated treatments. Among the plant height increase, average plant width increase, total plant weight and root weight, there was no observed significant difference between the treatments.

The highest rate of Ambrosia beetle attacks were found on both of the controls, inoculated and non-inoculated treatments of Charcoal + Kaolin, inoculated treatment of Charcoal + Kaolin combined with Permethrin and Subdue MAXX, non-inoculated treatment Charcoal + Kaolin with Subdue MAXX, inoculated and non-inoculated treatment of Subdue MAXX alone and inoculated and non-inoculated treatment of Permethrin and Charcoal + Kaolin. Both inoculated and non-inoculated treatments of Permethrin alone, non-inoculated control of Subdue MAXX, Permethrin and Charcoal+ Kaolin, inoculated and non-inoculated treatments of Subdue MAXX and Permethrin and inoculated treatments of Subdue MAXX and Charcoal + Kaolin had significantly fewer ambrosia beetle attacks as compared to the positive control. No phytotoxicity was observed during the study.

 

Tables

Table 1. Fungicides, biofungicides, and host plant defense inducers used in this study

Treatmenta

Application rate

Product group

Manufacturerb

ml/liter

g/liter

Actigard 50 WG

 

0.30

Host plant defense inducer

Syngenta

Aliette 80 WDG

 

3.74

Host plant defense inducer

Bayer

Empress Intrinsic

0.47

 

Strobilurin

BASF

Interface Stressgard

6.25

 

Strobilurin + dicarboximide

Bayer

MBI-110

10.00

 

Biofungicide

Marrone

Orkestra Intrinsic

0.78

 

Strobilurin + succinate dehydrogenase inhibitor

BASF

Pageant Intrinsic

 

1.35

Strobilurin + succinate dehydrogenase inhibitor

BASF

RootShield Plus+ WP

 

0.60

Biofungicide

BioWorks

Segovis

0.25

 

Piperidinyl-thiazole isoxazoline

Syngenta

Signature Xtra Stressgard

 

5.99

Host plant defense inducer

Bayer

Subdue MAXX

0.16

 

Phenylamide

Syngenta

Tartan Stressgard

3.12

 

Strobilurin + triazole

Bayer

a Active ingredients (% A.I.): Actigard = acibenzolar-S-methyl (50%); Aliette = aluminum tris (0-ethyl phosphanate) (80%); Empress Intrinsic = pyraclostrobin (23.3%); Interface Stressgard = trifloxystrobin (1.44%) + iprodione (23.1%); MBI-110 = Bacillus amyloliquefaciens strain F727; Orkestra Intrinsic = pyraclostrobin (21.26%) + fluxapyroxad (21.26%); Pageant Intrinsic = pyraclostrobin (12.8%) + boscalid (25.2%); RootShield Plus+ = Trichoderma harzianum Rifai strain T-22 (1.15%) + T. virens strain G-41 (0.61%); Segovis = oxathiapiprolin (18.7%); Signature Xtra Stressgard = aluminum tris (0-ethyl phosphanate) (60%); Subdue MAXX = mefenoxam (22%); Tartan Stressgard = trifloxystrobin (4.17%) + triadimefon (20.86%).

b BASF=BASF Corporation, Florham Park, NJ; Bayer=Bayer AG, Monheim an Rhein, Germany; BioWorks=BioWorks Inc., Victor, NY; Marrone =Marrone Bio Innovations, Inc., Davis, CA; Syngenta=Syngenta International AG, Basel, Switzerland

Table 2. Management of Phytophthora root rot of flowering dogwood using fungicides, biofungicides and host defense inducers in preventative application 3 weeks before flooding for 1 day flooding

Treatment 

Mean ± SE 

Plant height (cm) 

Plant width (cm) 

Plant weight (g) 

Root weight (g) 

Disease severity (%)* 

Actigard 

0.58 ± 0.08bcd

0.21 ± 0.75abc 

  0.76 ± 0.09f

0.44 ± 0.05d

  30.00 ± 4.28cdef

Aliette 

0.92 ± 0.42abc 

0.00 ± 0.38abc 

  1.21 ± 0.16abc 

0.77 ± 0.36ab 

20.00 ± 2.89f

Empress 

0.42 ± 0.15cd

-0.29 ± 0.44abc 

  0.76 ± 0.05f

0.51 ± 0.05cd 

25.83 ± 3.52cdef

MBI-110 

0.75 ± 0.25a-d 

-0.38 ± 0.42abc 

  0.79 ± 0.16ef 

0.53 ± 0.12bcd 

50.83 ± 4.36ab 

ON Gard

1.17 ± 0.17ab 

1.08 ± 0.49a* 

  1.39 ± 0.15a* 

0.84 ± 0.08a 

38.33 ± 5.43bc

Orkestra 

0.58 ± 0.08bcd

-0.21 ± 0.70abc 

  1.01 ± 0.04b-f

0.72 ± 0.06abc 

30.83 ± 3.96cdef

Pageant 

0.67 ± 0.21bcd 

-0.88 ± 0.37bc 

  1.11 ± 0.09a-e 

0.77 ± 0.07ab 

33.33 ± 5.87cde

Rootshield Plus+ 

0.67 ± 0.11bcd

-1.38 ± 0.79c

  0.89 ± 0.06c-f

0.62 ± 0.06a-d 

36.67 ± 7.03cd

Segovis 

 0.58 ± 0.24bcd

-0.17 ± 0.50abc 

  0.89 ± 0.11c-f

0.63 ± 0.09a-d 

20.83 ± 4.36ef 

Subdue MAXX

0.58 ± 0.08bcd

-1.13 ± 0.66bc

  0.73 ± 0.08f

0.51 ± 0.07cd 

25.00 ± 5.16def

Signature Xtra

1.33 ± 0.38a*

0.67 ± 0.90ab 

1.28 ± 0.14ab 

0.82 ± 0.08a 

20.83 ± 5.39ef

Tartan 

0.50 ± 0.13cd 

-0.67 ± 0.94abc 

  0.87 ± 0.13def 

0.62 ± 0.09a-d 

 33.33 ± 3.80cde

Interface

0.92 ± 0.37abc

0.13 ± 0.76abc

1.19 ± 0.17a-d

0.84 ± 0.11a*

23.33 ± 4.59ef

Negative control 

0.42 ± 0.08cd 

-0.79 ± 0.86abc 

1.15 ± 0.14a-d

0.82 ± 0.12a 

  0.00± 0.00g 

Positive control 

0.25 ± 0.11d

-1.00 ± 0.93bc

  0.79 ± 0.10ef

0.25 ± 0.11d 

  53.33 ± 4.59a 

0.0746

0.4931 

0.0003

0.0027

<.0001

 

Table 3. Management of Phytophthora root rot of flowering dogwood using fungicides, biofungicides and host defense inducers in preventative application 3 weeks before flooding for 3 days flooding

Treatment 

Mean ± SE 

Plant height (cm) 

Plant width (cm) 

Plant weight (g) 

Root weight (g) 

Disease severity (%)* 

Actigard 

0.67 ± 0.11bcd

-3.13 ± 0.70bc

  0.57 ± 0.02c

0.40 ± 0.02d

  50.00 ± 5.92bcd 

Aliette 

1.00 ± 0.13a-d 

0.54 ± 0.47a 

  1.00 ± 0.14b 

0.65 ± 0.09abc 

23.33± 6.91g

Empress 

0.75 ± 0.11bcd

-1.46 ± 0.78abc 

  0.87 ± 0.05bc

0.59 ± 0.06bcd 

40.83 ± 5.07def

MBI-110 

0.67 ± 0.11bcd

0.21 ± 0.43a 

  0.62 ± 0.07c 

0.42 ± 0.05cd

56.67 ± 5.27abc 

ON Gard

1.17 ± 0.38ab 

-1.04 ± 1.03abc 

  1.04 ± 0.19ab 

0.69 ± 0.12ab 

42.50 ± 7.27cde

Orkestra 

0.50± 0.00d

-1.63 ± 1.07abc

  0.62 ± 0.07c 

0.45 ± 0.05bcd

49.17 ± 4.36bcd

Pageant 

1.08 ± 0.15abc 

-0.79 ± 0.93ab 

  0.78 ± 0.11bc 

0.57 ± 0.10bcd 

52.52 ± 5.44bcd

Rootshield Plus+ 

0.83 ± 0.17bcd

-3.25 ± 1.06c 

  0.65 ± 0.08c

0.48 ± 0.09bcd

53.33 ± 4.94bcd

Segovis 

 0.92 ± 0.15bcd

-1.13 ± 0.69abc 

  0.89 ± 0.10bc 

0.64 ± 0.06abc 

22.50 ± 5.28g 

Subdue MAXX

0.92 ± 0.15bcd 

0.58 ± 0.36a 

  0.83 ± 0.11bc 

0.54 ± 0.10bcd 

26.67 ± 4.01fg

Signature Xtra

1.50 ± 00.47a

0.50 ± 1.20a 

1.34 ± 0.15a* 

0.84 ± 0.09a* 

30.00 ± 6.71efg

Tartan 

0.58 ± 0.08cd 

-0.46 ± 0.68a

  0.73 ± 0.10bc 

0.50 ± 0.08bcd

 42.50 ± 7.39cde 

Interface

0.75 ± 0.17bcd

-1.63 ± 1.22abc

0.75 ± 0.18bc

0.53 ± 0.12bcd

61.67 ± 4.77ab

Negative control 

0.75 ± 0.28bcd

-0.08 ± 0.70a 

0.80 ± 0.08bc 

0.50 ± 0.04bcd

  0.00± 0.00h 

Positive control 

0.75 ± 0.11bcd

-0.54 ± 0.70a 

0.81 ± 0.16bc

0.58 ± 0.11bcd 

  71.67 ± 4.01a 

0.1230

0.0255

0.0016

0.0458

<.0001

 

Table 4. Management of Phytophthora root rot of flowering dogwood using fungicides, biofungicides and host defense inducers in preventative application 3 weeks before flooding for 7 days flooding

Treatment 

Mean ± SE 

Plant height (cm) 

Plant width (cm) 

Plant weight (g) 

Root weight (g) 

Disease severity (%)* 

Actigard 

0.42 ± 0.20d

-0.08 ± 0.35abc 

  0.53 ± 0.07cd

0.28 ± 0.04d 

55.83 ± 4.36b 

Aliette 

1.17 ± 0.21abc 

1.21± 0.44a

  0.80 ± 0.12ab 

0.43 ± 0.08a-d 

58.33 ± 5.43b

Empress 

0.75 ± 0.25bcd

-1.58 ± 0.21de 

  0.67 ± 0.09bcd

0.43 ± 0.08a-d 

33.33 ± 3.33c

MBI-110 

1.08 ± 0.15abc 

-0.92 ± 0.63cde

  0.46 ± 0.05d

0.26 ± 0.04d 

63.33 ± 4.41ab 

ON Gard

1.42 ± 0.37a

0.92 ± 0.40a

  1.05 ± 0.14a 

0.57 ± 0.08a 

57.50 ± 4.23b

Orkestra 

0.67 ± 0.11cd 

-1.08 ± 0.38cde 

  0.60 ± 0.07bcd

0.34 ± 0.06bcd 

61.67 ± 3.07b

Pageant 

1.17 ± 0.11abc

-0.71 ± 0.22b-e

  0.82 ± 0.12ab 

0.50 ± 0.11ab

55.00 ± 5.32b

Rootshield Plus+ 

0.75 ± 0.11bcd

-1.04 ± 0.79cde 

  0.64 ± 0.10bcd

0.39 ± 0.07a-d 

56.67 ± 4.77b

Segovis 

0.75 ± 0.11bcd

-0.08 ± 0.40abc 

  0.50 ± 0.05d 

0.26 ± 0.04d 

57.50 ± 5.28b 

Subdue MAXX

0.67 ± 0.11cd 

-0.63 ± 0.30b-e

  0.59 ± 0.03bcd 

0.34 ± 0.03bcd

32.50 ± 3.35c

Signature Xtra

0.75 ± 0.37bcd

0.67 ± 0.17ab 

  0.79 ± 0.13abc 

0.48 ± 0.12abc 

37.50 ± 7.39c 

Tartan 

0.67 ± 0.11cd

-1.92 ± 1.22e

  0.49 ± 0.06d

0.28 ± 0.04d

 55.50 ± 6.06b 

Interface

1.25 ± 0.25ab

-0.25 ± 0.47a-d

   0.83 ± 0.11ab

0.43 ± 0.06a-d

63.33 ± 5.27ab

Negative control 

0.83 ± 0.11bcd 

-1.50 ± 0.35cde

    0.49 ± 0.05d

0.31 ± 0.06bcd 

 3.33 ± 1.67d

Positive control 

0.42 ± 0.15d 

-0.96 ± 0.57cde 

  0.53 ± 0.10d

0.30 ± 0.07cd

  75.83 ± 4.17a 

0.0383

<.0001

0.0004 

0.0324

<.0001

 

Table 5. Management of Phytophthora root rot of flowering dogwood using fungicides, biofungicides and host defense inducers in preventative application 1 week before flooding for 1 day flooding

Treatment 

Mean ± SE 

Plant height (cm) 

Plant width (cm) 

Plant weight (g) 

Root weight (g) 

Disease severity (%)* 

Actigard 

1.25± 0.31bcd

0.96 ± 0.35b

  0.88 ± 0.08c

0.59 ± 0.06de

  18.33 ± 5.58bcd 

Aliette 

2.08 ± 0.30ab 

1.33 ± 0.33ab 

  1.29 ± 0.10a

0.87 ± 0.06ab 

7.50 ± 1.71 de 

Empress 

1.42 ± 0.30bcd

1.00 ± 0.38b 

  0.93 ± 0.17c

0.65 ± 0.06cde

9.17 ± 1.54de

MBI-110 

1.08 ± 0.20cd

1.79 ± 0.38ab 

  0.74 ± 0.07c

0.53 ± 0.06e

25.83 ± 5.97bc 

ON Gard

1.50 ± 0.26bcd 

0.88 ± 0.51b 

  0.88 ± 0.11c 

0.63 ± 0.08cde

26.67 ± 11.30b

Orkestra 

0.83 ± 0.48d

0.46 ± 0.59b 

  0.88 ± 0.08c

0.60 ± 0.05cde

16.67 ± 2.79bcd

Pageant 

0.83 ± 0.28d 

0.58 ± 0.69b 

  1.22 ± 0.21ab 

0.81 ± 0.13abc 

13.33 ± 3.07cd

Rootshield Plus+ 

2.00 ± 0.32bc 

1.04 ± 0.66b 

  0.83 ± 0.07c 

0.56 ± 0.05de

20.00 ± 5.63bcd

Segovis 

 1.67 ± 0.25bcd 

0.88 ± 0.21b 

  1.25 ± 0.08ab 

0.88 ± 0.04ab 

9.17 ± 3.27de

Subdue MAXX

1.83± 0.28bc

1.25 ± 0.39ab 

  0.84 ± 0.08c 

0.54 ± 0.06de

10.00 ± 1.83de

Signature Xtra

3.00 ± 0.48a*

2.54 ± 0.68a* 

1.26 ± 0.09a

0.75 ± 0.12a-d 

14.17 ± 4.55bcd 

Tartan 

1.17 ± 0.28bcd 

0.92 ± 0.26b 

  0.82 ± 0.14c 

0.61 ± 0.10cde

 15.00 ± 2.89bcd 

Interface

2.00 ± 0.43bc

1.58 ± 0.37ab

1.38 ± 0.09a

0.96 ± 0.09a*

11.67 ± 3.33de

Negative control 

1.17 ± 0.36bcd 

1.00 ± 0.34b 

0.80 ± 0.12c

0.56 ± 0.08de

  0.00± 0.00e

Positive control 

1.33 ± 0.28bcd 

0.79 ± 0.65b 

  0.98 ± 0.03bc

0.67 ± 0.01b-e 

  55.00 ± 4.28a 

0.0010 

0.3029

0.0003

0.0003 

<.0001

 

Table 6. Management of Phytophthora root rot of flowering dogwood using fungicides, biofungicides and host defense inducers in preventative application 1 week before flooding for 3 days flooding

Treatment 

Mean ± SE 

Plant height (cm) 

Plant width (cm) 

Plant weight (g) 

Root weight (g) 

Disease severity (%)* 

Actigard 

1.17± 0.25abc

1.33 ± 0.58a

  0.80 ± 0.10c

0.53 ± 0.06cd

  36.67 ± 5.58b-e

Aliette 

1.75 ± 0.21a* 

0.54 ± 0.21b-d

  1.06 ± 0.18abc

0.72 ± 0.12abc 

25.83 ± 5.39 b-f 

Empress 

1.33 ± 0.36abc 

0.87 ± 0.37b-d

  1.02 ± 0.13abc

0.69 ± 0.08b-d

35.00 ± 7.19b-f

MBI-110 

1.33 ± 0.21abc 

1.21 ± 0.31ab 

  0.91 ± 0.10abc

0.57 ± 0.07bcd

48.33 ± 6.41b 

ON Gard

0.75 ± 0.11c

0.42 ± 0.35b-d

  0.83 ± 0.11bc 

0.56 ± 0.08bcd

35.83 ± 7.24b-f

Orkestra 

0.75 ± 0.21c 

0.08 ± 0.53b-d 

  0.82 ± 0.23c

0.54 ± 0.16cd

41.67 ± 9.10bc

Pageant 

1.08 ± 0.35abc 

1.08 ± 0.67abc 

  1.20 ± 0.12ab 

0.82 ± 0.09ab 

22.50 ± 3.59ef

Rootshield Plus+ 

1.17 ± 0.25abc 

1.25 ± 0.68a 

  0.91 ± 0.13abc 

0.62 ± 0.11b-d

33.33 ± 5.43b-f

Segovis 

 1.67 ± 0.31ab 

1.08 ± 0.45abc

  1.19 ± 0.19ab

0.83 ± 0.15ab 

25.00 ± 7.30def

Subdue MAXX

0.75 ± 0.31c 

-0.21 ± 0.58d

  1.00 ± 0.13abc 

0.66 ± 0.08b-d

20.00 ± 6.06f

Signature Xtra

1.67 ± 0.31ab

-0.04 ± 0.14bcd 

1.26 ± 0.11a*

0.87 ± 0.09a* 

20.83 ± 3.75ef 

Tartan 

1.00 ± 0.18bc 

-0.013 ± 0.14cd 

  0.68 ± 0.08c 

0.42 ± 0.06d 

 40.83 ± 5.39bcd 

Interface

1.08 ± 0.30abc

0.75 ± 0.43b-d

1.05 ± 0.10abc

0.75 ± 0.09abc

25.00 ± 6.71def

Negative control 

1.00 ± 0.22bc 

0.63 ± 0.33b-d

0.95 ± 0.08abc

0.62 ± 0.05b-d 

  0.00± 0.00g

Positive control 

0.83 ± 0.11c 

0.17 ± 0.58b-d

  0.89 ± 0.10abc

0.61 ± 0.06b-d

  67.50 ± 2.81a 

0.0684

0.1988 

0.1260

0.0778 

<.0001

 

Table 7. Management of Phytophthora root rot of flowering dogwood using fungicides, biofungicides and host defense inducers in preventative application 1 week before flooding for 7 days flooding

Treatment 

Mean ± SE 

Plant height (cm) 

Plant width (cm) 

Plant weight (g) 

Root weight (g) 

Disease severity (%)* 

Actigard 

0.83± 0.21ab

-0.04 ± 0.46b 

  0.72 ± 0.11b-e

0.52 ± 0.07cde

  59.17 ± 4.90e

Aliette 

1.08 ± 0.33ab 

1.13± 0.21ab 

  1.33 ± 0.05a

0.90 ± 0.05a

26.67 ± 4.94g

Empress 

0.92 ± 0.24ab 

0.54 ± 0.69ab 

  0.69 ± 0.06b-e

0.52 ± 0.06cde

61.67 ± 4.01de

MBI-110 

0.92 ± 0.15ab 

0.29 ± 0.36ab 

  0.90 ± 0.11bc

0.64 ± 0.06bcd 

70.83 ± 2.71cde 

ON Gard

1.00 ± 0.22ab 

0.38 ± 0.52ab 

  0.75 ± 0.11b-e

0.57 ± 0.10b-e

74.17 ± 4.90bc

Orkestra 

1.00 ± 0.39ab 

0.92 ± 0.58ab 

  0.83 ± 0.09bcd

0.64 ± 0.08bc 

71.67 ± 2.47bcd

Pageant 

1.42 ± 0.20a 

0.46 ± 0.28ab 

  0.63 ± 0.05de 

0.48 ± 0.04cde 

64.17 ± 4.55cde

Rootshield Plus+ 

1.50 ± 0.37a

0.54 ± 0.33ab

  1.18 ± 0.06a 

0.99 ± 0.18a 

39.17 ± 5.69f

Segovis 

 1.00 ± 0.29ab 

0.25 ± 0.67ab 

  0.65 ± 0.06cde 

0.39 ± 0.04de

72.50 ± 3.35bcd

Subdue MAXX

1.17± 0.31ab 

0.88 ± 0.38ab 

  0.91 ± 0.12b 

0.62 ± 0.09b-e

28.33 ± 5.58fg

Signature Xtra

1.50 ± 0.18a

1.63 ± 0.52a* 

 1.29 ± 0.08a

0.93 ± 0.08a

25.83 ± 4.17g

Tartan 

1.08 ± 0.24ab 

1.25 ± 0.63ab 

 0.74 ± 0.16b-e

0.59 ± 0.15b-e

71.33 ± 5.70bcd 

Interface

0.67 ± 0.17b

0.92 ± 1.00ab

0.64 ± 0.03de

0.43 ± 0.04cde

83.33 ± 3.80ab

Negative control 

1.08 ± 0.20ab 

1.04 ± 0.46ab 

1.17 ± 0.11a

0.79 ± 0.07ab

  0.00± 0.00h

Positive control 

0.92 ± 0.30ab 

0.25 ± 0.32ab 

  0.56 ± 0.04e

0.39 ± 0.04e 

  91.33 ± 3.43a 

0.6303 

0.7299 

<.0001

<.0001

<.0001

 

Table 8. Management of Phytophthora root rot of flowering dogwood using fungicides, biofungicides and host defense inducers in curative application for 1 day flooding

Treatment 

Mean ± SE 

Plant height (cm) 

Plant width (cm) 

Plant weight (g) 

Root weight (g) 

Disease severity (%) 

Aliette 

2.67 ± 0.60c

-0.63 ± 0.83bc 

  1.31 ± 0.20bc

1.77± 0.31bc 

16.67± 3.80b 

Empress 

1.50 ± 0.13c

-1.67 ± 1.17cd 

  1.18 ± 0.13bcd 

1.55 ± 0.17bcd

18.33 ± 4.01b 

Orkestra 

1.25 ± 0.28c

-2.25 ± 0.39cd

  1.28 ± 0.15bc 

1.63 ± 0.17bc 

17.50± 3.35b

Pageant 

1.92 ± 0.30c

-1.92 ± 0.59cd

  1.07 ± 0.11bcd

1.39 ± 0.12cd

15.00 ± 1.83b

Segovis 

1.33 ± 0.28c 

-2.58 ± 0.70cd

  1.10 ± 0.14bcd

1.27 ± 0.08cd 

15.00 ± 2.89b

Subdue MAXX

1.50 ± 0.37c 

-3.21 ± 0.48de

  0.94 ± 0.14cd

1.10 ± 0.12d 

17.50 ± 3.35b

Signature Xtra

4.50 ± 0.89b

1.08 ± 1.49ab 

  1.49 ± 0.23ab

2.25 ± 0.41ab 

10.83 ± 2.01bc

Tartan 

1.58 ± 0.20c

-1.79 ± 0.41cd

  0.82 ± 0.06d

1.10 ± 0.07d

15.00 ± 3.16b 

Interface 

6.33 ± 1.52a* 

2.63 ± 0.88a* 

  1.76 ± 0.20a* 

2.83 ± 0.38a* 

19.17 ± 4.90b

Negative control 

1.67 ± 0.36c

-2.79 ± 0.25cde

  0.97 ± 0.12d 

1.24 ± 0.15d

  0.00 ± 0.00c

Positive control 

1.25± 0.17c

-5.17 ± 1.33e 

  0.81 ± 0.13cd

1.10± 0.15cd

  49.17 ± 7.79a 

0.0419

<.0001

0.0011

0.0073

0.0582

 

 

 

Table 9. Management of Phytophthora root rot of flowering dogwood using fungicides, biofungicides and host defense inducers in curative application for 3 days flooding

Treatment 

Mean ± SE 

Plant height (cm) 

Plant width (cm) 

Plant weight (g) 

Root weight (g) 

Disease severity (%)* 

Aliette 

1.50 ± 0.18c 

-4.17 ± 1.51d 

  0.88 ± 0.21d 

1.31± 0.30cd

32.50 ± 5.88b

Empress 

1.67 ± 0.25c

-3.21 ± 0.22d

  0.87 ± 0.09d 

1.18 ± 0.11cd

25.83 ± 4.36bcd 

Orkestra 

1.58 ± 0.38c 

-2.17 ± 0.45cd

  1.07 ± 0.09cd 

1.37 ± 0.13cd

25.00 ± 4.47bcd 

Pageant 

1.83 ± 0.74c 

-0.42 ± 1.58c 

  1.30 ± 0.22c

1.85 ± 0.44c

15.83 ± 2.39de

Segovis 

2.50 ± 0.71c 

-2.13 ± 0.84cd

  1.02 ± 0.13cd 

1.51 ± 0.28cd

16.67 ± 3.07de

Subdue MAXX

1.50 ± 0.26c 

-2.71 ± 0.54cd

  1.00 ± 0.05cd 

1.31 ± 0.07cd

19.17 ± 2.39cde 

Signature Xtra

7.08 ± 0.55b 

2.71 ± 1.30b 

  1.79 ± 0.13b 

2.72 ± 0.16b

13.33 ± 1.67e

Tartan 

1.17 ± 0.36c

-1.92 ± 0.84cd

  0.75 ± 0.09d

1.00 ± 0.12d

15.83 ± 2.39de

Interface 

9.67 ± 1.33a* 

6.54 ± 0.48a* 

  2.22 ± 0.17a* 

3.98 ± 0.47a* 

28.33 ± 4.771bc 

Negative control 

1.08 ± 0.15c 

-2.83 ± 0.67cd

  0.93 ± 0.09cd 

1.20 ± 0.11cd

  0.00 ± 0.00f 

Positive control 

1.92± 0.20c

-1.79 ± 0.82cd

  1.07 ± 0.14cd 

1.43± 0.19cd

  60.00 ± 5.77a 

<.0001

<.0001

<.0001

<.0001

<.0001

 

Table 10. Management of Phytophthora root rot of flowering dogwood using fungicides, biofungicides and host defense inducers in curative application for 7 days flooding

Treatment 

Mean ± SE 

Plant height (cm) 

Plant width (cm) 

Plant weight (g) 

Root weight (g) 

Disease severity (%)* 

Aliette 

2.00 ± 0.48bc

-2.63 ± 1.49abc 

  0.94 ± 0.34ab

1.20± 0.41bc

40.83 ± 8.70bcd

Empress 

1.42 ± 0.20bc

-4.71 ± 0.76bc 

  0.46 ± 0.11b

0.63 ± 0.13c

48.33 ± 6.15b 

Orkestra 

1.00 ± 0.26c 

-5.63 ± 1.04c

  0.58 ± 0.11b

0.77 ± 0.13bc

50.00 ± 5.63b 

Pageant 

4.50 ± 1.65a*

0.17 ± 1.87a 

  1.29 ± 0.33a*

2.04 ± 0.60a*

40.00 ± 7.85bcd

Segovis 

1.50 ± 0.22bc 

-2.63 ± 0.49abc

  0.59 ± 0.10b 

0.85 ± 0.11bc

25.83 ± 3.75d

Subdue MAXX

1.17 ± 0.21bc

-3.751 ± 0.79bc

  0.72 ± 0.13b 

0.99 ± 0.17bc

24.17 ± 4.55d 

Signature Xtra

3.42 ± 1.10ab 

-0.13 ± 1.55a

  0.98 ± 0.22ab 

1.48 ± 0.35ab

29.17 ± 8.80d

Tartan 

1.25 ± 0.21bc

-2.42 ± 0.43abc

  0.54 ± 0.08b 

0.83 ± 0.12bc

 39.17± 5.83bcd

Interface 

2.58 ± 0.49abc 

-2.29 ± 1.77abc 

  0.70 ± 0.20b 

1.07 ± 0.27bc

43.33 ± 5.111bc 

Negative control 

1.67 ± 0.25bc

-2.17 ± 0.95abc

  0.93 ± 0.18ab 

1.26 ± 0.22abc 

  0.00 ± 0.00e

Positive control 

2.83 ± 1.55abc 

-2.96 ± 0.90abc

  0.72 ± 0.17b 

0.99± 0.20bc

  70.83 ± 3.00a 

0.0699

0.0460 

0.1512 

0.0623 

<.0001

 

 

 

 

 

 

 Table 11. Mean (± SE) plant growth data, ambrosia beetles attack and disease severity of dogwood trees treated with fungicides, insecticides and activated charcoal + kaolin

Treatment 

Application Rate

 

Mean ± SE 

ml/liter

g/liter

Plant height (cm) 

Plant width (cm) 

Ambrosia Beetles Attack

Plant weight (g) 

Root weight (g) 

Disease severity (%) * 

Permethrin (Ino)

12.5

 

5.67 ± 1.23a

2.58 ± 1.49a 

7.33 ± 4.62b-f

673.67 ± 102.45a

    371.58± 77.311a 

57.50 ± 5.59ab 

Permethrin (Non)

12.5

 

8.00 ± 2.66a

2.17 ± 2.20a 

7.50 ± 2.43b-f

778.58 ± 97.41a

    461.92 ± 93.05a 

18.33 ± 4.59e*

Subdue MAXX + Charcoal +Kaolin + Permethrin (Ino)

 

 

7.83 ± 3.91a

-1.00 ± 1.28a

12.00 ± 5.39a-e

891.75 ± 248.44a 

    611.50 ± 206.77a 

60.00 ± 4.65ab

Subdue MAXX + Charcoal +Kaolin + Permethrin (Non)

 

 

2.00 ± 1.18a

-0.08 ± 1.05a 

6.50 ± 1.98def

645.92 ± 51.98a 

    383.00 ± 48.21a

15.83 ± 4.36e* 

Subdue MAXX + Permethrin (Ino)

 

 

9.33 ± 4.02a

1.17 ± 1.14a

3.67 ± 1.98f

 649.75 ± 77.23a 

   377.25 ± 69.61a 

43.33 ± 10.78bcd

Subdue MAXX + Permethrin (Non)

 

 

8.50 ± 3.22a

-1.50 ± 1.33a

6.17 ± 2.24ef

 686.58 ± 80.45a 

   423.33 ± 60.30a 

11.67 ± 2.11e*

Charcoal + Kaolin (Ino) 

 

60+60

8.00 ± 2.42a

2.33 ± 1.12a

13.83 ± 4.48ab

 735.25 ± 62.27a

   465.08 ± 50.01a

70.00 ± 4.28a 

Charcoal + Kaolin (Non)

 

60+60

9.17 ± 3.77a

 1.00 ± 1.13a

14.17 ± 5.50a

 717.00 ± 92.04a

   452.33 ± 58.83a

54.17 ± 4.55ab 

Subdue MAXX (Ino) 

0.16

 

4.00 ± 1.75a 

-0.08 ± 1.28a

13.00 ± 4.04abc 

 718.08 ± 125.43a

   473.25 ± 98.49a 

60.00 ± 2.24ab

Subdue MAXX (Non)

0.16

 

6.17 ± 2.83a 

-0.75 ± 0.77a

11.33 ± 4.72a-e 

 692.00 ± 81.68a

   410.75 ± 60.39a 

25.00 ± 4.47de

Subdue MAXX + Charcoal + Kaolin (Ino)

 

 

0.33 ± 2.35a 

-1.25 ± 0.66a

7.17 ± 2.52c-f

  624.50 ± 81.14a

   356.42 ± 48.52a 

49.17 ± 3.52abc

Subdue MAXX + Charcoal + Kaolin (Non)

 

 

6.83 ± 2.21a 

-0.33 ± 1.15a

12.50 ± 5.38a-d 

  862.50 ± 160.90a

   588.25 ± 128.04a 

25.83 ± 3.52cde

Permethrin + Charcoal + Kaolin (Ino)

 

 

9.50 ± 4.15a

1.08 ± 1.18a 

8.17 ± 4.83a-f

  647.17 ± 87.39a

   348.25 ± 50.56a 

58.33 ± 5.27ab

Permethrin + Charcoal + Kaolin (Non)

 

 

4.67 ± 2.19a

 -0.67 ± 1.50a 

8.83 ± 1.40a-e

  708.58 ± 96.34a

   407.33 ± 69.50a 

20.83 ± 4.90de

Positive Control

 

 

9.33 ± 2.82a

0.83 ± 0.95a

13.83 ± 3.71ab

  544.67 ± 50.33a

   279.58 ± 25.21a 

70.83± 3.27a 

Negative Control

 

 

4.67 ± 1.38a

 1.83 ± 1.33a

13.67 ± 2.62ab

  706.12 ± 112.69a

   385.17 ± 60.07a 

8.33 ± 1.05e 

 

0.4884

0.3353

0.6912

0.8686

0.4845

<.0001

                   

Ino: Inoculated treatments

Non: Non-inoculated treatments

Participation Summary
1 Farmer participating in research

Educational & Outreach Activities

5 Consultations
1 Published press articles, newsletters
6 Webinars / talks / presentations

Participation Summary:

57 Farmers
150 Ag professionals participated
Education/outreach description:

Neupane, K., Ojha, V., Oliver, J., Addesso, K.M., and Baysal-Gurel, F. 2020. Integration of alternative strategies to optimize Phytophthora cinnamomi management in flowering dogwood in flooding condition.  130th Meeting of the Tennessee Academy of Science. November 21, 2020 (Poster presentation).

Neupane, K. and Baysal-Gurel, F. 2020. Management of Phytophthora cinnamomi using fungicides, biofungicides, host plant defense inducers and fertilizer in simulated flooding events. 130th Meeting of the Tennessee Academy of Science. November 21, 2020 (Oral presentation).

Baysal-Gurel, F., Neupane, K., Brown, M.S., Oliver, J.B., Addesso, K.M., and Ojha, V., 2020. Can we control ambrosia beetles as well as Phytophthora root rot using fungicides and biofungicide on plants exposed to flooding? Virtual Annual Entomology Meeting. November 11-25, 2020 (Oral presentation).

Ojha, V., Oliver, J.B., Addesso, K.M., Baysal-Gurel, F., and Deren, V. 2020. Integration of systemic fungicides and permethrin for control of nursery-attacking ambrosia beetles. Virtual Annual Entomology Meeting. November 11-25, 2020 (Poster presentation).

Neupane, K., Ojha, V., Oliver, J.B., Addesso, K.M., and Baysal-Gurel, F. 2020. Integration of alternative strategies to optimize Phytophthora cinnamomi and ambrosia beetle management in flowering dogwoods under flooding condition. Tennessee Entomological Society 47th Annual Meeting, October 9, 2020 (Oral presentation).

Baysal-Gurel, F. 2020. Webinar. Southern Region Green Industry Webinar hosted by UGA Center for Urban Ag on Thursday, 12 November 2020.

Baysal-Gurel, F. 2020. Suppressing Soilborne Diseases on Woody Ornamentals. Chase Digest October 2020 Issue Volume 8(10).

 

Project Outcomes

5 Farmers reporting change in knowledge, attitudes, skills and/or awareness
5 Farmers changed or adopted a practice
3 New working collaborations
Project outcomes:

N/A

Knowledge Gained:

N/A

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.