DEPARTMENT OF AGRICULTURE
Plant Industry Division
QUARANTINE AGAINST IMPORTATION OF SYMPTOMLESS CARRIERS OF PEACH MOSAIC INTO MESA COUNTY COLORADO
8 CCR 1203-16
Statement of Basis and Purpose
Adopted February 10, 2015-Effective March 30, 2016
Statutory Authority
These amendments to the rules are proposed for adoption by the Commissioner of the Colorado Department of Agriculture pursuant to his authority under § 35-4-110 C.R.S of the Colorado Pest Control Act. 
Purpose
The purpose of this permanent rule amendment is to repeal the Rules currently published at 8 CCR 1203-16 in their entirety. 
Factual and Policy Issues
1.	The California Department of Food and Agriculture eliminated their quarantine against the peach mosaic virus in 2015. This prompted the Colorado Department of Agriculture staff to request a review of this Rule be conducted by Colorado State University. Dr. Jane Stewart reviewed current scientific literature and California’s decision to cease their quarantine against peach mosaic virus.
2.	Peach mosaic is a low risk pathogen to Colorado peaches and therefore cessation of quarantine will not increase the threat of peach mosaic in Colorado due to the following factors:
A.	Pathologists from the University of California, Davis, University of California Riverside and Colorado State University have not observed the peach mosaic in orchards for over 50 years in their respective states. In Colorado, three infected trees were recovered in 1991, but no trees have been identified since that time.
B.	The mite, Eriophyes insidiosus (peach bud mite) is not an efficient vector. A study conducted in 1998 found that a single mite had at most a peach mosaic transmission rate of 17% (gispert et al. 1998, Plant Disease).
C.	Prunus certification is completed in California and likewise in Colorado. Therefore, checks for peach mosaic could be conducted during the Prunus certification process. Published polymerase chain reaction primers currently exist for peach mosaic, so testing either plant material or the vector could be amended to the current Prunus certification process.