Advisory statement on hand cleaning bulk citrus

     Fruit that moves between bulk citrus zones must be either sprayed within 14 days of harvest with an approved insecticide or field cleaned. The original plan for field cleaning was to require mechanical brushes or rollers to dislodge leaves and twigs and jostle the fruit so that adult psyllids would leave it.  The current practice is to allow hand cleaning of leaves and twigs from bins as it is being picked and dumped into the bins.  The plan before the CPDPC sets a limit on the number of leaves that a bin of harvested fruit can contain to be considered “clean”. However, it has not been shown that the number of leaves in a bin is statistically correlated with the number of psyllids in bins, nor is it indicative of the potential risk of moving psyllids when the fruit is moved, as psyllids can move on the fruit itself.

     We do know that psyllids are transported with bulk citrus (Halbert et al., 2010) and can survive for some time on fruit alone without leaf material present (Hall & McCollum, 2001). Research conducted in a Florida packinghouse demonstrated that some psyllids remained on harvested fruit even after being mechanically brushed or rolled and 0.5% of those psyllids were alive (Walse et al., 2014).  It is likely that the number of psyllids on fruit will be even higher in the absence of brushes or rollers.  The strategy of using pickers to hand-remove leaves from the bins at harvest will not reduce the undesirable transportation of psyllids around the state and could significantly increase the risk of HLB spreading to new production areas.

     It is the consensus of the DATOC expert panel that approval of this regulatory plan should not be based upon the unfounded assumption that limiting the number of leaves in a bin minimizes the risk of psyllids in the bin or is a safe and acceptable practice to prevent transportation of psyllids between zones.

References

Halbert, S.E. et al. 2010. Trailers transporting oranges to processing plants move Asian citrus psyllids.  Florida Entomologist 93(1):33-38.

Hall, D.G. and G. McCollum. 2011. Survival of adult Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae), on harvested citrus fruit and leaves. Florida Entomologist 94(4): 1094-1096.

Walse, S., A. T. Dossey, D. E. Bellamy and L. Jimenez.  2014.  Removing ACP from California citrus during post-harvest cleaning and packing.  Citrograph Summer 2014: 64-69.

View the advisory statement

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DATOC is sponsored by the Citrus Research Board and the California Citrus Pest and Disease Prevention Program.