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OSO Fungicide

OSO® is a polyoxin D zinc salt fungicide that controls diseases on vegetable and fruit crops.

Oso hero image

OSO is for use against the following diseases/pathogens on the following crops:


  • Anthracnose
  • Early blight
  • Gray mold
  • Gummy stem blight
  • Powdery mildew
  • Scab
  • Target leaf spot/Corynespora leaf spot

Pome and Stone Fruits:

  • Alternaria leaf spot
  • Leaf blotch
  • Powdery mildew
  • Scab
  • Botrytis blossom blight


  • Black scurf
  • Early and late blight
  • White mold


  • Alternaria brown spot
  • Botrytis rot
  • Septoria spot

OSO Applications

Active Ingredient: Polyoxin D zinc salt

Rates: Low rate (3.75 fl. oz/acre) for preventive applications before onset of visible disease, in periods of low disease pressure or in a tank mix with other fungicides for resistance management. Higher rates (6.5 to 13.0 fl. oz/acre) when disease pressure is high or in stand-alone applications.

Re-entry Interval: 4 hours

Pre-harvest Interval (PHI): 0

Exempt: Residue tolerance (no MRLs)

Application Method: Ground, chemigation

PPE: Long-sleeved shirt and long pants, socks, shoes and chemical-resistant gloves


FIFRA Recommendation 2(ee) Labels

Organic Crops

OMRI Listed®:

This product is OMRI Listed, therefore it is determined by the Organic Materials Review Institute (OMRI) to be suitable for use in certified organic production.

WSDA Certified:

This product has been verified to comply with the USDA National Organic Standards, issued by the Washington State Department of Agriculture. The WSDA Organic Program is accredited as a certification agent by USDA. As a certification agent of the National Organic Program, WSDA Organic Program's role is to inspect and certify organic operations; verifying that they are meeting the requirements of USDA organic standards.

NOP Approved:

This product is approved for organic production by the National Organic Program (NOP), a marketing program housed within the United States Department of Agriculture (USDA) Agricultural Marketing Service, the agency that sets marketing standards. The NOP mission is to develop and implement national standards that govern the marketing of agricultural products as organically produced, to facilitate commerce in fresh and processed food that is organically produced, and to assure consumers that such products meet consistent standards.


WSDA Organic Certificate
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OMRI Certificate Printer friendly PDF format