Submitted to: Journal of Economic Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/17/2004
Publication Date: 12/1/2004
Citation: Fuester, R.W., Kozempel, M.F., Goldberg, N.M., Forster, L.D., Casillas, L.I., Swan, K.S. 2004. A novel non-chemical method for quarantine treatment of fruits: California red scale on citrus. Journal of Economic Entomology. 97(6): 1861-1867. 2004 Interpretive Summary: Insect pests on produce constitute a severe threat to American Agriculture. Although inspectors examine a significant amount of fruit and other produce coming into and leaving the country, the possibility of insect pests hitching a ride into the country (or out of the U.S. into another country) on produce is an ever present danger. Therefore, shipments of imported and exported commodities must often receive chemical treatments, usually with fumigants, to prevent this from happening. One of the most effective fumigants, methyl bromide, will be banned in 2005, because of environmental considerations. Therefore, it is desirable to find other technologies for quarantine treatment of fruit and other commodities. One possibility is the Vacuum-Steam-Vacuum (VSV) surface intervention process, a technology originally developed by ARS scientists to eliminate harmful micro-organisms on the surface of food stuffs. Using the California red scale on citrus as a model system, we conducted an initial trial of the VSV process for quarantine treatment against insects. Although the VSV process was not very effective in removing scales from lemons, the citrus crop used in the experiment, it consistently killed 100% of the scales present. Therefore, the VSV process might possibly be used in combination with high pressure washing to meet both low thresholds for cosmetic damage and the levels of scale mortality needed to meet stringent export or import requirements. Exploratory trials of this technology with other insects and commodities would appear to be indicated.
Technical Abstract: A process for removing and/or killing California red scale, Aonidiella aurantii (Maskell), from citrus fruit as a post-harvest treatment was evaluated. The process subjects the fruit to vacuum, steam, and vacuum that physically removes red scale from the fruit and kills those scales that are not removed from the fruit. Different numbers of cycles and steam temperatures were compared for efficacy in removing scale from lemons or killing those that remained. Multiple (2-3) cycles removed up to 96% of 1st molt scales on the fruit, but were much less effective in removing other stages, especially those that had advanced beyond the second instar. However, it was extremely effective in killing the scales remaining on the fruit. Although this process does not eliminate cosmetic damage caused by scale presence, it might be used in combination with high-pressure washers currently used in packing houses to allow importers and exporters to meet the most stringent quarantine requirements. Because of its killing power, this technique should be tried on other insects and commodities to see if it can be substituted for certain uses of methyl bromide.