Managing Diseases in the Greenhouse with Biologicals

Cheryl A. Smith Extension Professor, Plant Health Specialist

Tri-State GH Workshop 2016 Cultural methods must be employed to prevent pest problems

(Essential for effective use of any ‘chemical’ control)

(‘chemicals’ will not correct for poor horticultural methods) Cultural Components of GH IPM

Prevention - Sanitation - Humidity control (air circulation) - Scouting & Diagnosis / ID - pH & nutrient testing - Watering Sanitation!

Inspect incoming material

Start clean, keep it clean, end clean

sanitize benches, potting areas, mats, trays, irrigation system components keep hose nozzles off ground/floor

remove plant debris, weeds & algae Sanitation Needed!

Look under the benches! Why biologicals /biorationals

• As a tool to prevent pesticide resistance • Alternative to ‘conventional’ chemicals • As a tool for organic growers

Should be some in everyone’s toolbox Some points to keep in mind…

• Use preventatively!! – Won’t save a ‘situation’ • Must be used with cultural methods • Don’t use them like a chemical – Not as a corrective measure • Not like insect parasitoids and parasites – Many are good saprophytes…no ‘feeding’ Biologicals How do biological fungicides work?

• Exclusion by direct competition – (for colonization / living sites) • Antagonism / Antibiosis – metabolite production: toxins, antibiotics • Predation or parasitism Trichoderma attacking Rhizoctonia

www.bioworksinc.com How do biological fungicides work?

• Exclusion by direct competition – (for sites) • Antagonism / Antibiosis – metabolite production: toxins, antibiotics • Predation or parasitism • Competition for nutrients • Induce host resistance (ISR) How to use biological fungicides?

• use BEFORE disease occurs

• MUST be used in conjunction with cultural methods Biocontrol organisms

• Fungi – – Trichoderma spp. • different strains

• Bacteria – Bacillus spp. • different strains – Streptomyces spp. • different strains What for what?

Trichoderma – fungal diseases

Bacillus – Fungal & bacterial diseases

Streptomyces – fungal diseases

(in general…always some exceptions) Trichoderma spp.

Material: natural, soil-born fungus, various strains soil (or foliar) application MOA: exclusion, competition, antagonism/antibiosis, parasitism, growth enhancement NOP: Microbial, Non-synthetic, allowed

Toxicity: III “Caution” Bacillus spp.

Material: natural, saprophytic bacterium, various strains soil or foliar application MOA: competition, antagonism/antibiosis, growth enhancement, ISR NOP: Microbial, Non-synthetic, allowed

Toxicity: III “Caution” Streptomyces spp.

Material: natural, predominantly soil-inhabiting, bacterial and fungal characteristics, various strains soil or foliar application MOA: exclusion, antagonism/antibiosis, parasitism, growth enhancement NOP: Microbial, Non-synthetic, allowed

Toxicity: III “Caution” Soilborne ‘target’ pathogens

• Pythium • Rhizoctonia • Fusarium • Phytophthora • Thielaviopsis check for healthy roots

Not good Pythium root rot Pythium root rot – sloughing roots Blackened areas on roots (Thielaviopsis) Thielaviopsis

Calibrachoa stunt wilt Thielaviopsis root rot products for drench

RootShield (G, WP): Trichoderma harzianum T-22; Bioworks OMRI RootShield Plus T. harzianum + T. virens; Bioworks OMRI

Mycostop Streptomyces griseoviridis K61; AgBio OMRI Actinovate S. lydicus; Natural Industries OMRI products for drench

Cease Bacillus subtilis QST713; Bioworks OMRI Companion Biological Fungicide B. subtilis GB03; Growth Products (NO OMRI)

Triathalon BA B. amyloliquefaciens strain D747: OHP (NO OMRI) Rootshield (G, WP) root treatment

0 hr REI OMRI

Target Pathogens: Pythium Rhizoctonia Fusarium Thielaviopsis Cylindrocladium Rootshield Plus (G, WP)

0 hr REI (G, WP) 4 hr REI if dip or dust (WP) OMRI

Target Pathogens: Pythium Rhizoctonia Fusarium Thielaviopsis Cylindrocladium Phytophthora media-mix

Pro-Mix (BX, BRK, HP, LP15) Biofungicide B. pumilis GHA180 + mycorrhizae (Glomus intraradices); Premier (NO OMRI) Pro-Mix Biofungicide (BX, BRK, HP, LP15)

NOT OMRI

Some Target Pathogens: Pythium Phytophthora Rhizoctonia Fusarium Sclerotinia Some foliar ‘target’ pathogens

• PM • DM • Alternaria • Rhizoctonia (aerial blight) • Bacteria – Xanthamonas, Erwinia, Pseudomonas

Sedum - powdery mildew Pansy

Pansy - downy mildew Basil - downy mildew products for foliar application

Mycostop Streptomyces griseoviridis K61; AgBio OMRI Actinovate S. lydicus; Natural Industries OMRI Cease Bacillus subtilis QST713; Bioworks OMRI Companion Biological Fungicide B. subtilis GB03; Growth Products (NO OMRI) Triathalon BA B. amyloliquefaciens D747; OHP (NO OMRI) Mycostop

0-4 hr REI OMRI Soil & foliar

Target Pathogens: Fusarium Alternaria Phomopsis (root, stem & seed rots & wilt) Also listed for Botrytis Suppresses: Phytophthora Pythium Rhizoctonia

(Can be used same day with several fungicides) Actinovate SP T&O

0-1 hr REI OMRI Soil & foliar treatments (also vegetables & herbs)

Target Pathogens: Pythium Phytophthora Rhizoctonia Fusarium Verticillium Sclerotinia Botrytis Alternaria anthracnose Erwinia Xanthamonas Pseudomonas also DM & PM Companion Biological Fungicide 2-3-2L

0-4 hr REI NOT OMRI Soil & foliar treatments (also vegetables & herbs)

Some Target Pathogens: Pythium Rhizoctonia Fusarium wilt Sclerotinia Botrytis Alternaria Xanthamonas campestris also PM Cease

0-4 hr REI OMRI Soil & foliar Some Target Pathogens: Pythium Phytophthora Rhizoctonia Fusarium Sclerotinia DM & PM Botrytis Alternaria Cercospora Myrothecium Rust Erwinia Xanthamonas Pseudomonas Triathlon BA

4 hr REI (NOP , no OMRI)

Soil & foliar treatments (also vegetables & herbs)

Target Pathogens: Pythium Rhizoctonia Botrytis Fusarium Sclerotinia rust anthracnose fungal leaf spots bacterial leaf spots also DM & PM Efficacy trials

B. Subtilis (Cease) Botrytis (poinsettia) - as good control as Decree (Daughtrey, 2002) Impatiens DM – NO effect @ 4 or 8 qt rates (Warfield, 2013)

B. Subtilis (Cease) + Potassium Bicarb (Milstop) slowed Botrytis on tomato (Villavicencio, 2011) Efficacy trials Efficacy trials Efficacy trials

Done by Chase Horticultural Research Control of Xanthomonas on Geranium 90 82 80 70 No. spots

60 55 50 50 40 40 32 30 20 20 15 13 10 0 0

c c 5 0 6 8 o o 2 5 % % % 1 4 in n - - .5 -1 -2 - - n I 7 7 0 e e m m o 2 2 - s s a a N P P se a a C C a e e e C C C www.chasehorticulturalresearch.com Control of Pseudomonas leaf spot on Delphinium Products were applied three times on a weekly interval.

2.5 2.3

2 1.9

1.5

1 Number of spots/plant 0.7 0.7 0.5 0.5 0.3 0.3 0.2

0 Non Inoc P27- P27- ZT-1% Cam- Cam- Ce 15 25 16 48 ase- 1%

www.chasehorticulturalresearch.com Colletotrichum leaf spot on Cyclamen

4 3.5 3.5 3.2 3 2.6 Three sprays

2.5 2.2 2.2 on a 7-day 2 interval 2 1.8 1.8 1.5 1 1 0.5 0 c c o o 2 % c .4 4 6 -8 n n -3 1 a 1 -2 -1 d i I s - /D il- n 9 r n vi e e n o 1 a o s s o l 0 u N le a a c th 6 g C e e a ta 2 ra C C D n h r e C e P T www.chasehorticulturalresearch.com Eradication of powdery mildew on Rosemary with biocontrols and wetting agents

35 31.8 30 Number of colonies 25 23.4 19.6 20 14.2 15

10 8.4 8.8 4.4 3.8 5

0

r 6 1 6 -4 4 -8 rate te -1 - - % il - a e e te -1 s B A tt g a e p n m W e ita v s a o a li r o a C tr o A e in e a F H ct C L o A N www.chasehorticulturalresearch.com Black root rot control on Pansy

60 52 50 43 44 40 33 30 26 26 21 20

10

0

3336 Noninoc Inoculated Agri-TerraPlantShield Plant/3336Companion www.chasehorticulturalresearch.com Pythium root rot control on Geranium

Percent healthy roots - April 30 60 55

50 43 40 40 40 38 * 34 32 30 28 30 26 23 20

10

0

c c t o o n c te ix ld n ld X le n n ro A a m ie io ie X o i I -I t/ v o h n h A z n o c o i a ra o n A in B tS p tS M r N ti t r o n e e c c e o m a u T A i o l d A m R C P b re u P S www.chasehorticulturalresearch.com Triathlon BA

www.chasehorticulturalresearch.com Disadvantages of microbial fungicides

• may not work quickly • do not eradicate pathogen/rescue infected host • shorter shelf life • may be expensive • compatibility with other pesticides Regalia Biofungicide

Extract of giant knotweed Reynoutria sachalinensis 4 hr REI OMRI Soil & foliar treatments (also vegetables & herbs) MOA ISR, also translaminar

Target Pathogens: PM controlled very well Pythium Phytophthora Rhizoctonia Verticillium www.planetarium.ru

Native to northeast Asia, N. Japan, & far eastern Russia

www.utok.cz Efficacy trial

Study done in FL with Gerbera PM: 77% reduction with 1% Regalia

Has to be applied early, well-before disease is likely to occur.

Repeat applications…ISR takes time Some additional points to keep in mind…

• If not organic production: – Rotation with chemicals may give better results (than either alone) – Can help preserve usefulness of synthetic chemicals (prevent resistance) Cultural methods must be employed to prevent pest problems

Essential for effective use of any biological or chemical control In Summary

• Biocontrol (and biorational) products: – Aid in resistance management – Often have short REI – Some have plant health benefits – Can help to reduce ‘chemical’ use – Many are OMRI-listed – May have lower risk of phytotoxicity Questions?