Biological products are termed “biofungicides” if they are marketed for disease control or as “microbial inoculants” if they are sold to promote plant and/or soil health.  The distinction is often vague and can be based solely on their registration with EPA.  Manufactures of registered biofungicides claim that their products can suppress those diseases listed on the label when they are applied according to the directions.  In addition, these products are subjected to EPA regulations and worker protection standards. On the other hand, producers of microbial inoculants make no claim concerning disease suppression and do not have fungicide registration with the EPA.  They advertise growth promotion when their product is used according to the directions.

Both biofungicides and microbial inoculants are composed of beneficial organisms selected from natural environments.  These fungi, bacteria, and actinomycetes have been proprietarily formulated with different additives to enhance their storage life and field performance.  Nematodes and insects are also commonly used to suppress insect pests.  Biological products are formulated as powders for seed treatments, as granulars for soil incorporation, and as suspensions for root drenches and foliar sprays.  Biological products reduce disease by using different mechanisms, such as competition, antagonism, antibiosis, enhanced nutrient uptake, and/or by inducing host resistance.  Products that utilize several mechanisms may have increased activity and/or may inhibit a wider range of target pathogens.

Competition can be an effective mechanism used by biological control agents in reducing disease.  Before infection can occur, pathogens must make contact with the leaf, flower, or root.  This space is called the phylloplane (leaf and flower) or rhizosphere (root).  These areas provide nutrients through leakage and normal exudation.  Both beneficial and deleterious microbes compete for these substrates.  Many biological control agents suppress disease by occupying the available sites along the plant root or leaf and prevent pathogens from invading the tissue.  Biological control agents that use competition to suppress disease generally need to be applied in high densities before the pathogen is present.  Examples of products that use this mechanism are PlantShield®, Galltrol-A®, and nonpathogenic Fusarium species.

Antagonism in the rhizosphere or on the leaf can involve direct parasitism whereby the biological control agents attacks and feeds on the pathogen.  This mode of action is probably less frequent than other mechanisms of suppressing disease, but it does occur.  For this mechanism to be effective in controlling disease, the biological control agents must be present in the rhizosphere or leaf at the same time or before the pathogen appears.  Examples of products that use this mechanism are PlantShield® and AQ10®.

Antibiosis involves the production of secondary metabolites (toxins) that will inhibit growth of a pathogen.  These metabolites inhibit the pathogen by preventing germination or restricting their growth in the rhizosphere or on the phylloplane.  Biological control agents that use antagonism may not necessarily have to be present in high numbers, but they need to exert their antibiotic effect before infection occurs.  Once the pathogen has gained entry into the root, the antibiotic may have less effect.  An example of a product that uses this mechanism is SoilGard®.

Many biological control agents also can improve growth and suppress disease by increasing nutrient availability.  This could explain why treated plants are larger than untreated plants even when a pathogen is absent.  By altering pH or by exporting enzymes that dissolve insoluble elements, these biological products increase the availability of certain fertilizers.  This mode of action has not received as much attention as other mechanisms, but may become important in nutrient deficient soil mixes.  Products, such as PlantShield®, SoilGard®, and Deny®, have been observed to have this property.

Lastly, researchers have noted that some biological products can trigger the plant to turn on its own defense mechanisms.  Studies have found that plants exposed to certain biological products will produce salicylic acid, (a derivative of common aspirin), which in turns, travels to other parts of the plants and signals these tissues to activate their natural defense mechanisms.  This is new and exciting mechanism that has great promise for plant disease control.

Today, growers are using many biological products, but results can be variable.  Some evidence suggest that these varying results may be due to differences in the crop, soil mix, soil pH, fertilizer regimes, and disease pressure.  Highly susceptible plants may not respond to biological products as well as more tolerant crops.  Soil mixes may contain composted bark amendments that harbor their own microflora and may interact with the biological product.  The alkalinity (or acidity) of the irrigation water may also increase (or decrease) soil pH to levels where the biological products are less effective.  If high fertility levels persist, Pythium can caused much damage regardless of whether or not a biological product is present.  These factors that influence product efficacy need to be better understood.   A growing body of evidence suggests that certain products perform consistently on certain crop.  For example, the use of PlantShield on poinsettias has been associated with more healthy roots. 

Biorational products are formulated as solutions, wettable powders and emulsifiable concentrates.  Like biological products, they can also have different modes of action, but most function in a manner similar to chemical fungicides and have direct effects on the pathogen.  Most prevent spore germination, but some retard spore production and growth.  Some products may also induce resistance in the plant and may provide protection to other plant parts.  Biorational products, as well as biological products, have the greatest efficacy when used preventively. 

In the near future, growers can surely expect to see more and more products that utilized these and perhaps other mechanisms for fighting disease developed for the greenhouse industry.  Although these products add to our arsenal of weapons for management of diseases in the greenhouse, there is still much to be learned about how to “optimize” these products for each plant-soil mix system.  First of all the biological products are composed of living organisms, so storage conditions, soil and air temperatures, and use of other chemicals can compromise their efficacy.  Many biorationals that are composed of botanical extracts may also have shortened shelf lives.  Biological and biorational products may never become the “quick fix” that we enjoyed for so long with chemical fungicides, but they do offer some unique advantages over chemical fungicides, such as shorter re-entry intervals, better worker protection, less chemical residue worries, less consumer concerns, and less chance of resistance developing in the pathogen.  As with any management strategy, these products should be used within an IPM framework that includes sanitation, proper growing conditions, routine scouting, and proper diagnosis.  We may find that these many of these products work best in combinations with each other and in rotation with chemical fungicides. 

The following list is provides a current “snapshot” of certain products that have been examined on flowering ornamentals.  Many of these products are not yet available to the greenhouse industry.  However, if and when they become registered, biofungicides and biorationals, like chemical fungicides, must be registered with EPA so growers must read and follow the label to determine if the intended use has been approved.  As always, read the label. 

Actinovate Plus/M, Actino-Iron - Biofungicide. Organism is Streptomyces lydicus.  It is formulate as a granular (Actino-Iron) and as a drench (Actinovate Plus/M). Manufacturer/Distributor: Natural Industries, Inc. 6223 Theall Rd., Houston, TX 77066 Phone 1-281-580-1643, FAX 1-281-580-1643. 

Bio-Fungus - Biological Product- Organism is Trichoderma spp. Labeled for control of Sclerotinia, Phytophthora, Rhizoctonia solani, Pythium spp., Fusarium, Verticillium, Formulation: granular, wettable powder; sticks and crumbles, Application Method: applied after fumigation; incorporated in soil; sprayed or injected.  Manufacturer/Distributor: Grondortsmettingen DeCuester n.v., Fortsesteenweg 30, B-2860 St.-Katelijne-waver, Belgium; Phone 32-15-31-22-57; FAX 32-15-36-15  

Companion -Biological Product- Organism is Bacillus subtilis (strain GB03). Labeled for control of diseases caused by Rhizoctonia, Pythium, Fusarium and Phytophthora. Formulation: Soil drench, Manufacturer/Distributor Growth Products, P.O. Box 1259, Westmoreland Avenue, White Plains, NY 10602, Phone 1-800-648-7626. 

EKsPunge (Nutrol) -Biorational product- Active ingredient is Monopotassium phosphate. Labeled for control of powdery mildew for ornamentals, Manufacturer/Distributor Lidochem Inc, 20 Village court, Hazlet, NJ  07730 Phone (908) 888 8000 FAX (908) 264 2751. 

Fortune Aza -Biorational Product- Active ingredient is neem oil. Labeled for control powdery mildew on greenhouse ornamentals. Manufacturer/Distributor Fortune Biotech Ltd.

Fungastop -Biorational Product- Active ingredients are ascorbic and citric acids, mint oil, citrus pulp, fish oil, glycerol. Labeled for broad spectrum fungal disease control on ornamentals. Formulated as a spray. Manufacturer/Distributor:  Soil Technologies Corp., R R 4 Box 133, Fairfield IA 52556, USA, Phone: 515-472-3963 or 800-221-7645 Fax: 515-472-6189.

Fusaclean --Biological Product- Organism is Fusarium oxysporum (nonpathogenic). Labeled for control of Fusarium oxysporum, Formulation: spores, microgranule, Application Method: in drip to rock wool; incorporate in potting mix; in row, Manufacturer/Distributor: Natural Plant Protection, Route d'Artix B.P. 80,64150, Nogueres, France; Phone 33-559-84-10-45; FAX 33-559-84-89-55 (Registration pending).

Galltrol-A -Biological Product- Organism is Agrobacterium radiobacter Strain 84. Labeled for control of crown gall disease caused by Agrobacterium tumefaciens, Formulation: petri plates with pure culture grown on agar. Application Method: bacterial mass from one plate transferred to one gallon of nonchlorinated water; suspension applied to seeds, seedlings, cuttings, roots, stems, and as soil drench. Manufacturer/Distributor: AgBioChem, Inc., 3 Fleetwood Ct., Orinda, CA 94563, USA; Phone 1-510-254-0789. 

JMS Stylet-Oil -Biorational product- Active ingredient is paraffinic oil.  Labeled for control of black spot, Botrytis blight, and powdery mildew in roses. Manufacturer/Distributor: JMS Flower Farms, Inc. Phone: (561) 567-9241, 1105 25^th Ave., Fax: (561) 567-9394 Vero Beach, FL 32960 Web Site: www.stylet-oil.com. 

Kaligreen -Biorational Product- Active ingredient is potassium bicarbonate.  Labeled for control of powdery mildew in roses and in field and greenhouse ornamentals Manufacturer Toagosei Co., Ltd. Distributor Monterey Chemical Company, web site: www.montereychemical.com. 

Kodiak, Kodiak HB, Kodiak AT  -Biological Product- Organism is Bacillus subtilis Target Pathogen/Disease: Rhizoctonia solani, Fusarium spp., Alternaria spp., and Aspergillus spp. that attack roots, Formulation: dry powder; usually applied with chemical fungicides, Application: added to a slurry mix for seed treatment; hopper box treatment. Manufacturer/Distributor: Gustafson, Inc., P.O. Box 660065, Dallas, TX 75266, USA; Phone 1-972-985-8877; FAX 1-972-985-1696.

MilStop -Biorational Product- Active ingredient is potassium bicarbonate, Labeled for control of powdery mildew, downy mildew, Botrytis, and Alternaria leaf-spot on ornamentals Manufacturer/Distributor: Bioworks, Inc., 122 North Genesee St., Geneva, NY 14456 USA; Phone: 1-315-781-1703; FAX 1-315-781-1793. 

Mycostop -Biological Product- Organism is Streptomyces griseoviridis strain K61. Target Pathogen/Disease: Fusarium spp., Alternaria brassicola, Phomopsis spp., Botrytis spp., Pythium spp., and Phytophthora spp. that cause seed, root, and stem rot, and wilt disease.  Formulation: powder, Application: drench, spray or through irrigation system. Manufacturer/Distributor: Kemira Agro Oy, Porkkalankatu 3, P.O. Box 330, 00101 Helsinki, Finland; Phone 358-0-13-211; FAX 358-0-694-1375. US Distributor: AgBio Development Inc., 9915 Raleigh St., Westminster, CO 80030; Phone 303-469-9221; FAX 303-469-9598.

Nemastroy -Biorational Product -Active ingredient is chili and mustard oil extract. Labeled for control of nematode on greenhouse ornamental and foliage plants. Formulated as a drench. Manufacturer/Distributor:   Soil Technologies Corp. RR 4 Box 133, Fairfield IA 52556, USA, Phone: 515-472-3963 or 800-221-7645 Fax: 515-472-6189.  

Norbac 84C -Biological Product- Organism is Agrobacterium radiobacter strain K84. Target Pathogen/Disease: crown gall disease caused by Agrobacterium tumefaciens, Formulation: aqueous suspension, Application: root, stem, cutting dip, or spray, Manufacturer/Distributor: New BioProducts, Inc., 4737 N.W. Elmwood Dr., Corvallis, OR 97330 USA; Phone 503-752-2045. 

PlantShield -Biological Product- Organism is Trichoderma harzianum Rifai strain KRL-AG2 (T-22). Target Pathogen/Disease: Pythium spp., Rhizoctonia solani, Cylindrocladium, Thielaviopsis, Fusarium spp., and Botrytis. Formulation: granules or wettable powder, Application: granules mixed with soil or potting medium; powder mixed with water and added as a soil drench. Manufacturer/Distributor: Bioworks, Inc., 122 North Genesee St., Geneva, NY 14456 USA; Phone: 1-315-781-1703; FAX 1-315-781-1793. 

PreStop, Primastop --Biological Product- Organism is Gliocladium catenulatum, Target Pathogen/Disease: Pythium spp., Rhizoctonia solani, Botrytis spp., Didymella spp., Formulation: wettable powder, Manufacturer/Distributor: Kemira Agro Oy, Porkkalankatu 3, P.O. Box 330, 00101 Helsinki, Finland; Phone 358-0-13-211; FAX 358-0-694-1375. US Distributor: AgBio Development Inc., 9915 Raleigh St., Westminster, CO 80030; Phone 303-469-9221; FAX 303-469-9598.  

Rhapsody – Biological Product – Organism Bacillus subtilus QST 713Bio‘fungicide’ labeled for Bacterial diseases, Powdery mildew, Botrytis, Anthracnose, Alternaria, and Entomosporium. 

Compatible with Fungicides 4 REI AgraQuest, Inc., 1105 Kennedy Place, Davis, CA 95615 USA; Phone 1-530-750-0150; FAX: 1-530-750-0153. 

Remedy - Biorational Product- Active ingredient is potassium bicarbonate.  Labeled for control of powdery mildew disease in greenhouse.  Manufacturer: Bonide Products, Inc. 2 Wurz Ave. Yorkville, NY 13495 315-736-8231 /Distributor Gardener's Supply Co. 128 Intervale Rd. Burlington, VT 05401-2850, Phone 800-863-1700. 

Sunspray Ultra-Fine Spray Oil - Biorational product-Active ingredient is paraffinic oil.  Labeled for control of powdery mildew in greenhouse crops as well as outdoor zinnia, lilac, azalea, phlox and aster. Manufacturer: Sunoco Inc, Ten Penn Center1801 Market Street, Philadelphia, PA, 19103-1699, Phone (215) 977-3000. 

Taegro Biological Product- Organism is Bacillus subtilis var amyloliquefaciens. Target Crop/Pathogen: damping-off and root rot pathogens especially Rhizoctonia solani and Fusarium spp. Formulation: powder; Application: pre-plant incorporate, root dips, and soil drenches.  Manufacturer/Distributor: Taensa Inc. 28 Sherman CT P. O. Box 764, Fairfield, CT  06430. Phone (203) 256-0460.

Triact 70 -Biorational product- Active ingredient is neem oil. Labeled in the greenhouse for control of powdery mildew, downy mildew, leaf spot, Botrytis blight and black spot of roses. Manufacturer/Distributor: Thermo Trilogy, 9145 Guilford Road, Columbia, MD 21046 USA; Phone 1-301-604-7340; FAX 1-301-604-7015.

TriCon™ - Biotrational product – Active ingredient is borax and plant oils.  Contact fungicide/insecticide for mycelium and spores, curative properties of powdery and downy mildew.  Formulation: liquid. Manufacturer/Distributor: Bioworks, Inc., 122 North Genesee St., Geneva, NY 14456 USA; Phone: 1-315-781-1703; FAX 1-315-781-1793.