Any facility for plants involved in the propagation and growing of citrus nursery stock must be totally enclosed, with all doors, temperature regulation systems, blowers, door and vent closure mechanisms, sides, tops, other parts, other hardware, and joints built, maintained and operated to standards sufficient to exclude insects. The facility should comply with the requirements for interstate movement from Citrus Greening (CG) Quarantined Areas to All U.S. States, as specified in the "Interstate Movement of Citrus and Other Rutaceous Plants for Planting from Areas Quarantined for Citrus Canker, Citrus Greening, or Asian Citrus Psyllid" as published by the United States Department of Agriculture, Animal and Plant Health Inspection Service, Plant Protection and Quarantine; a link to the current version of that document can be found at: http://www.aphis.usda.gov/plant_health/plant_pest_info/citrus/. The specific structural requirements include the following.

1. (1) Exterior walls and top. Any combination of solid surfaces and screening may be used, as long as the structure excludes insects.

2. (2) Doors and doorways.

   1. (A) All doorways shall have a positive pressure air curtain, positive pressure double doors, or other mechanisms sufficient to prevent the entrance of any insects, both during operation of the door and while the door is closed.
   2. (B) All doors shall fit against the floor and door frame, so that no insect can enter.
3. (3) Other openings. Except for doors, all exterior openings for cooling pads, fans, vents or other parts of a structure to be operated under a certificate of registration must be covered with screening.
4. (4) Screen mesh size. The mesh size for any screening used in walls, doors, vent covers, or other parts of a structure to be operated under a certificate of registration shall not exceed 0.3 square millimeters (e.g., 0.547 x 0.547 mm or 0.5 x 0.6 mm).

Source Note:The provisions of this §21.61 adopted to be effective November 21, 2013, 38 TexReg 8189.