(a) Increase Tree Requirements. Increase trees or increase blocks shall meet all of the following requirements.
  (1) Budwood for propagating increase trees shall be obtained from a foundation or scion tree.
  (2) Increase trees shall be propagated and grown in a certified citrus nursery as specified in Subchapter D of this chapter (relating to Citrus Nursery Stock Certification Program).
  (3) Increase trees shall be budded on nursery rootstock which has not been budded previously. If re-budding is necessary, buds from the same source tree as the original bud shall be used.
(b) Increase Tree Structures. Increase trees must be held exclusively in an approved structure designated for increase trees or housed with other certified citrus nursery stock being grown in the approved structure, provided the two groups of plants are kept identifiably separate.
  (1) At no time shall any uncertified citrus nursery stock be inside the approved structure.
  (2) Increase trees may be grown in containers or planted in the ground.
  (3) Increase trees of different varieties and selections shall be kept distinctly apart and clearly identified to avoid the mixing of increase trees originating from different source trees.
(c) Labeling of Increase Trees.
  (1) Each lot of increase trees produced from the same lot of budwood from a specific foundation block tree shall be labeled for traceability with a unique identification number. The permanent label or tag shall include the variety, source tree identification number, and the month and year of budding.
  (2) Each lot of increase trees must be of the same cultivar, originating from the same foundation block source tree(s) and budded in the same month and year.
  (3) An increase tree identification map shall be maintained on site. The map shall be made available during an inspection or upon request by the department. The map must include the location of each group of increase trees by selection in the approved structure, the name of the selection, the number of trees in each lot, source tree identification number, and the month and year of budding.
(d) Duration of Use of Increase Trees. Increase trees of budwood to produce certified citrus, may be used as a source of certified budwood to produce certified citrus nursery stock for a period not to exceed 60 consecutive months. The 60 month duration begins on the first day of the month following the month in which the trees were budded.
  (1) Within the citrus zone: Citrus trees propagated from budwood that originated from increase trees shall not serve as a future source of certified budwood.
  (2) Outside of the Citrus Zone: Increase trees of noncommercial citrus varieties (as provided in §21.39) may be used as a source of budwood to produce certified citrus nursery stock provided the trees meet the requirements of this section.
(e) Inspection.
  (1) Testing and inspection of increase trees for pests and diseases. Increase trees shall be inspected and tested at a minimum of once prior to 12 months post-budding and at an interval not to exceed 12 months for citrus tristeza and citrus greening or any other pest of regulatory concern. The department shall collect samples for testing according to the sampling plan, "Survey Protocol in Exclusionary Facilities for the Interstate Movement of Citrus and Other Rutaceous Plants for Planting from Areas Quarantined for Citrus Greening, Asian Citrus Psyllid, and Citrus Canker," developed by the CPHST Plant Epidemiology and Risk Analysis Laboratory of the Plant Protection and Quarantine branch of USDA-APHIS. The cost of the laboratory analysis of the samples shall be borne by the owner of the nursery. The department will inspect trees for citrus canker and other pests of regulatory concern during facility inspection.
  (2) The increase block must be routinely inspected and treated to prevent pests and diseases. The department may issue a seizure order if a pest or disease is found. If an Asian citrus psyllid or other disease vector is found, the contents of the structure are subject to a seizure order based on risk assessment. The department may consult with a panel of experts for additional mitigation measures necessary to ensure the integrity of increase trees.
(f) Disposition of increase trees. Upon discontinuing use of an increase tree, the increase tree must be removed from the increase block and may be sold, planted, or destroyed.

Source Note: The provisions of this §21.36 adopted to be effective December 31, 2015, 40 TexReg 9626; amended to be effective March 22, 2018, 43 TexReg 1629