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Bacillus subtilis strain QST 713

Bacillus subtilis is a Gram positive, rod shaped bacteria, commonly found in soil. This bacterium is also known by the names hay bacillus, grass bacillus, or Bacillus globigii. Bacillus subtilis is an endospore forming bacteria, and the endospore that it forms allows it to withstand extreme temperatures as well as dry environments. Bacillus subtilis is considered and obligate aerobe, but can also function anaerobicly when in the presence of nitrates or glucose. It can be used to create proteases and amylase enzymes. Bacillus subtilis is not considered pathogenic or toxic and is not a disease causing agent.

Bacillus subtilis strain QST 713 as an active ingredient is a biological control agent for use on several minor crops to treat a variety of plant diseases and fungal pathogens including gray mold, powdery mildew, early and late blight, fire blight, scab, sour rot, bacterial spot, and walnut blight. Bacillus subtilis is a ubiquitous bacteria commonly found in various ecological niches including soil, water and air which does not have a history of pathogenicity from contact in the environment. In addition, there are other strains of B. subtilis which are registered as microbial pesticides.

Serenade Garden is made from a unique, patented strain (QST 713) of Bacillus subtilis. Bacillus subtilis strain QST 713 penetrates and destroys the disease pathogen, but does not harm beneficial insects or wildlife when used according to label directions.




Target Pathogens: Powdery mildew, Gray mold, Botrytis Blight, Botrytis Fruit Rot, Botrytis Neck Rot, Botrytis Leaf Blight, Brown patch Alternaria Leaf Spot, Anthracnose, Bacterial Crown Rot; Bacterial Leaf Blight ; Bacterial Canker, Sooty mold; Sour Rot; Southern Blight, Bacterial spot, Black Root Rot/Black Crown Rot, Brown Rot; Brown Rot Blossom; Brown Spot, Downy mildew, Early Blight, Fire Blight, Late Blight, Leaf Rust, Leaf Spots,Pink Rot.

Mode of Action: The bacterium, Bacillus subtilis, is prevalent in soils and has been found in a variety of habitats worldwide. The QST 713 strain of B. subtilis is known to be antagonistic toward many fungal plant pathogens. This antagonism may be achieved in several ways including nutrient competition, site exclusion, colonization, and attachment of the bacteria to the fungal pathogen. In addition, AgraQuest reports that the QST 713 strain of B. subtilis has been shown to induce plants' natural systemic resistance or systemic acquired resistance (SAR) against bacterial pathogens. These bacteria can stop plant pathogen spores from germinating, disrupt germ tube growth, and inhibit attachment of the plant pathogen to the leaf.

Application Tips: For best results, treat prior to foliar disease development or at the first sign of foliar disease infection. Repeat at 7-day intervals or as needed. Under conditions of high disease pressure, shorten the spray interval or, for ornamental plants, use the higher rate.

Serenade Garden can be applied any time of day, in full sun and high temperatures, without stressing or burning foliage. It can be applied up to and including the day of harvest. It is impossible to test all plants for phytotoxicity. To assure that the plants to be treated are not sensitive to the treatment, apply a small amount of the highest application rate of the product to a few leaves or the above ground portion of a plant and check within three days for signs of phytotoxicity.

Precautions and Safety Equipment: Minimize your exposure to pesticides.  Avoid contact with eyes.  Wear eye protection, long pants, a long-sleeved shirt, and a hat that can be washed after each use.  Always read label of individual product for additional directions. (UC IPM)

Acute Toxicity to People and Other Mammals

  • Toxicity rating: Not Acutely Toxic

Water Quality Rating

  • Absorbed runoff toxicity risk to fish rating: Low
  • Solution runoff toxicity risk to fish rating: Low
  • Source: UC IPM WaterTox Database (originally NRCS Pesticide Properties Database)

Impact on Natural Enemies

  • Overall toxicity rating: Low
  • Specific impacts: predatory mites (Low), parasitoids (Low), general predators (Low)

Impact on Honey Bees

  • Toxicity category: Apply at any time with reasonable safety to bees


Selected References

Mycobiology. 2013 Jun; 41(2): 108–111. Bacillus sp. BS061 Suppresses Powdery Mildew and Gray Mold. Young-Sook Kim, Ja-Gyeong Song, In-Kyoung Lee, Woon-Hyung Yeo, and Bong-Sik Yun.

Journal of Biocontrol Science and Technology. Volume 21, 2011 - Issue 11. Mechanisms of the biofungicide Serenade (Bacillus subtilis QST713) in suppressing clubroot. R. Lahlali , G. Peng , L. McGregor , B.D. Gossen , S.F. Hwang & M. McDonald


Pesticide Management for Bacillus subtilis. UC IPM Statewide Integrated Pest Management Program