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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Plant Pathology Research » Research » Publications at this Location » Publication #335677

Title: Alternative method of thermotherapy application in citrus

item Gottwald, Timothy
item Poole, Gavin
item Taylor, Earl
item KAINZ, JAMES - Applied Research Associates, Inc

Submitted to: International Research Conference on Huanglongbing
Publication Type: Abstract Only
Publication Acceptance Date: 12/20/2016
Publication Date: 5/18/2017
Citation: Gottwald, T.R., Poole, G.H., Taylor, E.L., Kainz, J. 2017. Alternative method of thermotherapy application in citrus. International Research Conference on Huanglongbing. 4(1):1/45.

Interpretive Summary: Heating citrus trees infected with HLB is a possible way to keep the trees in production for longer periods of time. Our concept is to use hot water, heated by the sun, to heat the trees, as opposed to the practice of “tenting” or application of steam. If this technique works as well as the tenting, it would be easier to apply, be able to do large numbers of trees at once, can be used on trees of varying age and size and requires virtually no changes to field citriculture methods.

Technical Abstract: Thermotherapy has shown promise as a method to extend the life and production lifespan of citrus that is infected with HLB. However, the logistics of the current methods of application can be difficult, and the damage to the tree can be severe. Therefore, alternative methods of applying high heat to a tree, with no external power and a minimum of user input, were tested. Since these methods all use water to transmit heat (as opposed to directly heating the air around a tree), the term “hydrothermotherapy” (or HTT) is used to describe them. The motivation for this alternative thermotherapy approach was to develop a method that could be applied to a large number of trees simultaneously at low cost. Approach: Water for these systems is heated using solar energy, and then the hot water is transmitted to the tree via flexible black hosing, which is wrapped around the trunk to allow heat transfer directly into the tree without damage to the leaves. The first project was done to determine the parameters needed for optimal treatment using the HTT systems. Trees were subjected to a set temperature for a set period of time, to determine the heat tolerance of the tree. Once this was determined, trees were treated with various HTT arrangements, for the given period of time, and the effect on the HLB concentration within the tree was determined. Results indicate that using solar heated water can be an effective way to apply thermotherapy to citrus trees.