Controlling Foliar Diseases With Microbial Fungicides

Lettuce Red, Powdery Mildew Disease Griffin Greenhouse Supplies
Powdery mildew on red lettuce

Lots of interesting terms surface when the discussion turns to “softer” approaches to pest control. Terms such as these can all be correctly applied to certain pesticides: microbial, beneficial, bio, biochemical, reduced risk and organic. The focus of this discussion will center on a group of microbial fungicides that have proven to be very useful for the greenhouse and nursery industries.

Although the products mentioned below are also labeled for certain root and crown-area diseases, foliar diseases will be our focus. They’re referred to as microbial fungicides because their active ingredients are biological organisms — in this case, different types of bacteria that utilize various modes of action to prevent and control foliar plant diseases. Cease and Companion contain different strains of Bacillus subtilis; Actinovate SP uses a different bacterium called Streptomyces lydicus.

To be sure, there are safe and effective traditional foliar fungicides available to greenhouse and nursery operators. Some of them even share one or two of the attributes of microbial fungicides that are listed below. So why might a grower consider a microbial fungicide? Two of the three products mentioned are OMRI-listed, meaning they appear on a list of products approved for use in the organic production of food and fiber. Many microbial fungicides have broad labels allowing them to be used on a wide range of ornamentals and many of the edible crops that continue to gain popularity. Resistance is possible with any pesticide but is probably less likely with the modes of action used by these microbial fungicides.

Primula acaulis, Botrytis, Disease, Griffin Greenhouse Supplies
Botrytis on primula

All of these products require short re-entry intervals (REIs) and modest amounts of personal protection equipment (PPE). As always, read and follow the entire pesticide label! There is general agreement that the buying public wants our industry to use the safest products available and these products should be viewed in that light.

Modes of action used by microbial fungicides are not always completely understood. Often, more than one mode of action is employed by the same organism, a helpful trait in terms of fending off pesticide resistance. Some of the more common modes of action include:

Antibiotic: Compounds are produced that have an inhibiting effect on plant pathogens. An example would be the creation of compounds that inhibit certain fungal and bacterial spores from germinating. This is probably the most important mode of action for foliar applications.

Competition: The beneficial organism depletes the treated area of “food” needed by the pathogen and thereby out-competes it for that location.

Exclusion: In this case, the beneficial organism grows in such a way that it populates the same area where the pathogen would try to become established. By getting there first, it physically excludes the pathogen.

Parasitism: The beneficial organism feeds directly on the pathogen, inhibiting it or killing it altogether.

 

Microbial FungicidesTrade NameShelf LifeOMRI Listed?
Primary Modes of Action
* primary mode of action utilized for foliar applications
Streptomyces lydicus, WYEC 108Actinovate SP T&O18 monthsYesExclusion, parasitism, *antibiotic
Bacillus subtilis, QST 713 strainCease2 yearsYes*Antibiotic, some competition
Bacillus subtilis, GB03Companion Hort Label2 yearsNo*Antibiotic, some competition

 

Other attributes these products hold in common:

• Based on modes of action, they should be considered primarily preventative fungicides.

• Tank mixing with a wide selection of other fungicides and insecticides is possible. Most bactericides should not be used; check with your supplier for compatibility information.

• Excellent plant and bloom safety, though it is always best to trial on a small number of plants before widespread use.

To ensure maximum success with these microbial fungicides, first compare labels to be sure they’re suitable for the diseases you wish to control. They are relatively short-lived on leaf surfaces so pay close attention to re-application intervals. As with other types of fungicides, managing the growing environment to reduce disease pressure is essential. Even the best fungicides will fail if growing conditions are favorable for disease development.

Topics:

Leave a Reply

More From Crop Inputs...
Hendriks-Half-Open-Roof_GGS

March 26, 2015

10 Greenhouse Products For First-Rate Growing Environments

From coverings to fork-lifts, greenhouse suppliers offer a variety of products to make growing easier. Check out the slideshow to learn more about these, plus several other products that can offer you value, versatility and durability.

Read More
Rose rosette on Knockout rose, April 2012. Photo credit: Alan Windham, University of Tennessee

March 25, 2015

$58 Million In APHIS Farm Bill Funding Will Support Horticulture Priorities

Nearly $58 million as been allocated by the USDA's Animal and Plant Health Inspection Service (APHIS) to support the industry's Plant Pest and Disease Management and Disaster Prevention Program, under Farm Bill Section 10007. The program will support mitigation efforts for specialty crops, including providing research and other funding to address plant pest and disease priorities for the specialty crop industry, including floriculture and nursery crops.

Read More
AFE scholarship_Ryan Dickson

March 25, 2015

AFE Educational Grant And Scholarship Application Deadlines Approaching

Apply now for American Floral Endowment (AFE) scholarships or educational grants. Applications can be found online. For educational grants for 2015-2016, applications must be submitted no later than June 1. Scholarship applications are due May 1. AFE will award $40,000 in scholarships for 2015.

Read More
Latest Stories
OxiPhos_BioSafe2

March 23, 2015

BioSafe Makes Label Changes To OxiPhos And ZeroTol 2.0

There have been some recent label changes made to the BioSafe Systems product OxiPhos, a systemic bactericide/fungicide that reduces downy mildew spores when tank mixed with ZeroTol 2.0.

Read More
Nufarm_logo

March 23, 2015

Nufarm Fungicides Now Registered For Use On Edible Crop…

Nufarm Americas announced label expansions for two of its fungicides that will provide more pest management options for the ornamental industry. The Cleary 3336 F and EG fungicides are now registered for use across a wider range of edible crops, including select greenhouse vegetables and transplants, herbs and backyard fruit.

Read More
ColeusDMLeafSporulation_Daughtrey

March 11, 2015

Research Gives Clues For Preventing Coleus Downy Mildew

Maintaining awareness of coleus downy mildew is more important than ever to safeguard these attractive plants for reliable garden performance.

Read More
Rose Rosette on Knockout rose, May 2013. Photo credit: Alan Windham, University of Tennessee

March 2, 2015

Rose Rosette Disease Fight Gets A Boost From Government…

In 2014, $4.6 million was awarded through the Farm Bill to tackle rose rosette disease, a devastating pathogen that affects one of the industry’s most important crops.

Read More
Fig 1 Leafy Gall On Leucanthemum Becky

March 2, 2015

How To Prevent Leafy Gall Before You Lose Plants

Leafy gall is a nasty disease that can go undetected until plant damage is done. Take these steps to protect your crops from infection.

Read More

February 17, 2015

A New Look At Biological Control: Can Plants Affect The…

The success of a biological control program depends on a number of factors including quality of natural enemies, timing of release, release rates and environmental conditions. However, what is typically not taken into consideration is how plants can affect the performance of natural enemies, including attack rate and searching ability. Biological control agents work hard to protect plants, but plants have ways to help themselves, too.

Read More

February 1, 2015

New Pest Control Products For Your Toolbox

Add one of these new insecticides to your IPM program for successful pest control.

Read More
IR-4_profile_Feb2015

January 29, 2015

IR-4: A Pest Management Resource For Growers

Almost 40 years ago, IR-4 (Interregional Research Project Number 4) began serving the ornamental horticulture industry, helping to facilitate the registration of pest management tools. IR-4 does this primarily by surveying growers about their pest management issues and then hosting workshops to review survey results and set priorities for the coming years. Most recently, IR-4 coordinated a meeting of researchers and industry members on pollinator health and neonicotinoid chemistries to start a discussion on the needed research. The next step will be to get the outcomes from that workshop out to the public.

Read More

January 28, 2015

Biocontrols 2015 Conference & Tradeshow: Peace Tree…

Lloyd Traven, a speaker at the upcoming Biocontrols 2015 Conference & Tradeshow, was one of the industry’s early adopters of biocontrols in the greenhouse. Traven, owner of Peace Tree Farm, is evangelical about the technology as an effective tool for resistance management, as well as improved plant quality that contributes to a grower’s bottom line.

Read More

January 27, 2015

Southwest Perennials Improves Production, Shortens Crop…

A father-and-son team find LEDs deliver a higher rooting rate for cuttings propagated under the lights.

Read More
Wainwright-web-620x349

January 22, 2015

Quality Control With Biocontrols

Make sure the shipment of beneficials that just arrived is viable and ready to go to work in your greenhouse, nursery, or field. Here are five steps you can take to ensure success with your biocontrols.

Read More

January 9, 2015

6 New Fertilizer Products For Healthy Plants

These five products add even more options for delivering nutrients to the root zone.

Read More

January 7, 2015

Fertilizers And The Future

As growers look for new ways to cut costs and conserve resources, fertilizer and equipment companies are offering products that strive to save water, reduce toxic runoff and keep chemicals out of the equation.

Read More

December 31, 2014

Gain Greater Control Of Fertilizer With Automated Ferti…

University researchers look at integrating irrigation and fertilization with the help of water sensors to reduce fertilizer treatments and improve application timing.

Read More
As directed by EPA, the bee hazard icon appears in the Directions For Use for each application site for specific use restrictions and instructions to protect bee and other pollinators.

December 9, 2014

Fact Sheet: The Value Of Neonicotinoids To Turf And Orn…

An extensive study of the diverse turf and ornamental industry (“The Green Industry”) reveals that neonicotinoids are the top-rated products used by professionals to control their most important pests in greenhouses, landscapes, lawns, nurseries and trees.

Read More
As directed by EPA, the bee hazard icon appears in the Directions For Use for each application site for specific use restrictions and instructions to protect bee and other pollinators.

December 9, 2014

New Study Finds Neonicotinoids Are Top-Rated Products F…

According to results of a survey by AgInfomatics, professionals in the turf and ornamental industries fear the loss of neonicotinoid products would reduce the quality of their plants and services, increase costs and negatively impact their ability to manage pest resistance.

Read More

December 2, 2014

Grow-Tech Announces BioStrate, Its Newest Hydroponic Gr…

Grow-Tech LLC recently announced the release of BioStrate Felt, a biobased textile specifically engineered for the growing of hydroponic microgreens and baby salad greens.

Read More

November 25, 2014

Former Harris Seeds Co. CEO, Per Jensen, Passes At 85

A passion for plants defined long-time industry influencer.

Read More