Stem and Root Diseases A. R. Chase

Transcription

1 Stem and Root Diseases 2017 A. R. Chase

2 Color, Strength, Development

3 Fusarium Diseases

4

5

6 Fusarium Wilt/Stem Rot

7 What else attacks mums? Pythium alone and with Fusarium, Phytophthora, Erwinia/borer

8 What else attacks mums? Sclerotium rolfsii (Southern blight)

9 Fusarium Crown Rot on Hosta /17 9/25 10/ untreated control Orkestra 8 oz Orkestra 10 oz Orkestra 13 oz Pageant 16 oz 3.2

10 Cylindrocladium Diseases

11 Cylindrocladium - Boxblight Disease severity (total of dropped leaves and number of spots) on two boxwood cultivars Green Velvet Tide Hill Untreated control Orkestra 6 oz Orkestra 8 oz Orkestra 10 oz Pageant 12 oz

12 Cylindrocladium Pachysandra Cultivars Disease severity (total of dropped leaves and Pachysandra identity # spots/plant (with fungicide) P. axillaris Windcliff' 10 b 143 b P. terminalis Common P. terminalis Crinkled P. terminalis Green Carpet P. terminalis Green Sheen P. terminalis Variegated 75 a 340 a 11 b 68 b 9 b 51 b 17 b 98 b 19 b 137 b # spots/plant (no fungicide)

13 Medallion (12-fludioxonil) Heritage (11-azoxystrobin) or Mural (11-and 7), Empress Intrinsic (11-pyraclostrobin), Pageant Intrinsic (11-pyraclostrobin and 7- boscalid) or Orkestra Intrinsic (11- pyraclostrobin and 7-fluxapyroxad) Terraguard (3-triflumizole)

14 Pythium and Phytophthora Characteristics Spread easily by water Require water to spread and infect Multiply quickly Long-lived resting spores Flagella on zoospores Pythium spp. can be good saprophytes

15 Sporangia on roots Oospores in roots Zoospores

16 Phytophthora Diseases

17 Phytophthora aerial blight on vinca Noninoculated Inoculated Micora Adorn Noninoculated Inoculated Aliette 1.25 lb Aliette 4 lb Alude 26 oz Alude 54 oz 0 7 July 24 July 31 July 7 August 0 1 August 8 August 15 August

18 Control of Aerial Phytophthora on Vinca (Aggressive, Mefenoxam-resistant Florida Strain) % Plants Infected DAT 14 DAT 22 DAT Inoculated Adorn 4 floz Subdue Maxx 1 floz Fenstop 14 floz Orvego 14 floz Micora 8 floz Segovis 2.4 floz Segway 3 floz Segway 6 floz

19 Aliette (33-fosetyl aluminum) and many others Adorn (43-fluopicolide) (tank-mix as directed) Subdue MAXX (4-mefenoxam) Stature SC(40-dimethomorph) OR Orvego (40 and 45- ametoctradin) OR Micora (40-mandipropamid) Terrazole or Truban (14-etridiazole) FenStop (11-fenamidone) or Empress (11-pyraclostrobin) Segway O (21-cyazofamid) Segovis (49-OXTP-solatenol)

20 Pythium Root Rots

21 Effect of fungicide treatment with and without KleenGrow on Pythium root rot of New Guinea Impatiens (Daughtrey-Cornell) Noninoc Inoc SMAXX Heritage Segway Alone KleenGrow

22 Efficacy of Empress 250 FS on Pythium Root Rot on Poinsettia A J Palmateer, Univ. FL Noninoculated Inoculated Empress 1 oz Empress 2 oz Empress 3 oz Empress 6.1 oz Heritage 1 oz day interval 28-day interval 4.0 Poinsettia root rot severity in 6 inch pots. Root rot ratings were taken using the following scale: 0= no symptoms, 1= <10%, 2= 10-30%, 3= 30-50%, 4= 50-75% and 5= >75%.

23 Effect of Plant and Pythium Species on Disease Severity (Hausbeck, Michigan State University) Fungicide treatment Non-inoculated control Pythium aphanidermatum Pythium irregulare Pythium ultimum Actinovate Adorn Fenstop Heritage RootShield Segway O Subdue MAXX Terrazole Vital Inoculated control Fungicide treatment Non-inoculated control Pythium aphanidermatum Pythium irregulare Pythium ultimum Actinovate Adorn Fenstop Heritage RootShield Segway O Subdue MAXX Terrazole Vital Inoculated control Results of trials on geranium (left) and snapdragon (right) for control of Pythium diseases. The numbers are the area under the disease progress curve. Boxes in green were the best in each column.

24 Subdue MAXX (4-mefenoxam) consider adding KleenGrow to control resistant strains) Segway O (21-cyazofamid) Terrazole or Truban (14-etridiazole) RootShield Plus (nc-trichoderma harzianum and Trichoderma virens) Empress Intrinsic (11-pyraclostrobin)

25 Rhizoctonia Diseases

26 Rhizoctonia attacks stems, leaves and roots

27 Rhizoctonia creates webbing

28 Rhizoctonia Root Rot on Viburnum % Rhizoctonia Inoculated control Noninoculated control RootShield Plus SoilGard Mural Empress Pageant

29 Controlling Rhizoctonia Blight on Boston Fern by Dr. Aaron Palmateer % infection 10 0 Noninoculated Inoculated 5 Chipco ProStar 7 Heritage 4 Medallion

30 Medallion (12-fludioxonil) or Palladium (12-fludioxonil and 9-cyprodinil) Heritage, or Mural, Empress Intrinsic or Pageant Intrinsic (11 strobilurins) 3336, Fungo, OHP-6672 (1-thiophanate methyl) Affirm (19-polyxin-D) RootShield or RootShield Plus (44-Trichoderma harzianum and T. virens) preventatively and root rot mainly

31 Thielaviopsis root rot

32 Thielaviopsis spores

33 Black Root Rot Control on Pansy (Daughtrey, Cornell University) TREATMENT RATE/100 GAL Untreated control e Inoculated control ab Veranda O 4 oz 0.4 c Veranda O 6 oz 0.4 cd Veranda O 8 oz 0.5 d Disarm O 480SC 4 oz 0.2 ab Disarm O 480SC 8 oz 0.3 b Aliette 12.8 oz 0.2 a OHP oz 0.6 e DRY TOP WEIGHT (G)

34 Black Root Rot Control on Vinca (Daughtrey, Cornell University) Rate/ % healthy Treatment 100 gal. roots Water Noninoculated d Water Inoculated bc Cleary s oz 65.0 d Veranda O 8 oz 63.0 d Affirm 8 oz 61.1 d

35 Black Root Rot Rotation OHP-6672, Fungo, 3336 (1-thiophanate methyl) Affirm (19-polyoxin D) to a lesser degree Heritage (11- azoxystrobin), Orkestra Intrinsic (11-pyraclostrobin and 7- fluxapyroxad) Terraguard (3-triflumizole) Medallion (12-fludioxonil)

36 PATHOGEN Steaming and Control of Soilborne Pathogens (thirty minutes) NO TRT 113F Cylindrocladium scoparium 97% 56% 0 Phytophthora ramorum 85% 7% 0 Pythium irregulare 98% 23% 0 Thielaviopsis basciola 98% 63% 0 122F AND ABOVE

37 Get an accurate diagnosis Use IPM Choose effective products Apply to the right site Use the right rate and treatment interval Rotate products for resistance management Know when to quit

38 YouTube.com/ChaseAgricultural Chase Digest ChaseBase Chase Archives Ask Ann Custom consulting/research 937 Tierra Verde Circle Cottonwood, AZ

39 ...There is always a practical solution QUESTIONS???