The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service issued an interim rule that will permit the interstate movement of nursery stock even from areas quarantined for citrus canker, citrus greening, sweet orange scab and the presence of Asian citrus psyllid infestations.

The rule, published April 28, could prevent a gap in the domestic citrus supply in years to come.

The quarantine rules for various diseases and pests often prevented any movement of plants out of quarantine zones. The interim rule — while still highly restrictive — has harmonized the various quarantine rules, said Larry Hawkins, spokesman for the USDA.

The quarantines were preventing nurseries from delivering new citrus trees to commercial growers who wanted to expand their groves and/or replace existing groves, said Bob Blakely, director of industry relations for Exeter-based California Citrus Mutual.

“This (the rule) will allow nursery stock grown in protective structures to be shipped to growers,” he said. “Many nurseries have been — due to the threat of citrus greening — moving their stock into these protective structures as a proactive move and doing so at great expense.”

California Citrus Mutual was among the grower groups who brought to the attention of federal regulators the fiscal problems nurseries were encountering, Blakely said.

Certificates and limited permits will be issued only for shipments of plants originating from facilities that operate under a compliance agreement with APHIS, meet strict standards for the production of disease-free plant material and employ safeguards during packing and movement, according to a news release.

“This rule will provide much-needed economic relief for citrus-producing nursery growers in the quarantine areas,” Gregory Parham, APHIS administrator, said in the release. “Most of these nurseries are small businesses that have been impacted by the previous quarantine measures. To allow this new movement out of the quarantine areas, the rule establishes rigorous, science-based safeguarding measures that will protect all citrus-producing states.”

The rule does not override California law, which prevents the shipping of certain plants and commodities from Florida to California, Blakely said.

For more information on citrus greening, visit The Grower's Citrus Greening Resource Center .