The following procedures are based on the California Department of Food and Agriculture (CDFA) approved guidelines to certify plants growing in Clark County free from Ozonium root rot fungus (Phymatotrichum omnivorum). Growers or nursery plant producers must adopt this process in full before shipments can be certified. 

Protocol A: Field Grown Plants or Nursery Stock (in contact with native soil) 

1. Starting plant material must:
   1. Originate from either a certified source or a non-infested area OR
   2. Be propagated exclusively in one of the following soil types:

1. Soil that originates from certified property, OR

2. Soil less media, OR

3. Non-Clark County, NV soil that originates from a non-infested area, OR

4. Soil that is steam pasteurized (160-180 degrees F for 30 minutes)

2. Alfalfa (Medicago sativa) indicator plants must be grown in the field throughout the property and inspected by the Nevada Department of Agriculture on the following schedule:

   1. If the plant spacing is 25 feet or less, 2-3 inspections during growing season for two years, OR

   2. If the plant spacing is greater than 25 feet, 2-3 inspections during growing season for three years, OR

   3. If the plant spacing is greater than 40 feet, certification cannot be accomplished.

3. Samples of plants and roots must be collected during each inspection and submitted to the NDOA plant pathology lab for analysis. An annual inspection is required to confirm continued freedom from Ozonium root rot (Phymatotrichum omnivorum) on nursery site.

4. Positive detection of Phymatotrichum omnivorum on the property at any time will revoke the certification. The property will not be qualified for re-certification.

Protocol B: Greenhouse Grown Plants (without contact with native soil) 

1. Starting plant material must:
   1. Originate from either a certified source or a non-infested area, OR
   2. Be propagated exclusively in the certified greenhouse with one of the following soil types:

1. Commercial soil-less media, OR

2. Non-Clark County, NV soil that originates from a non-infested area, ORS

3. Soil that is steam pasteurized (160-180 degrees F for 30 minutes)

2. Plants must be grown in soil types specified above and on benches 3 feet above ground or without contact with native soil during entire growing period.
3. The facility must have a good ground barrier in the area for production activities such as soil mixing, potting, temporary storage of plants/pots, loading and unloading plants, etc. Ground barrier can be concrete slab or durable ground fabric /weed barrier without rips or tears.
4. Finished potted plants must be placed in a clean place with solid ground barrier prior to shipping, or be directly loaded from greenhouse benches for shipping.
5. The facility will be subjected to initial inspection to ensure above production requirements, followed by additional two inspections during each production period.
6. If above production requirements cannot be met, alfalfa indicator plants will be applied as specified in protocol A.