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United States Department of Agriculture

Agricultural Research Service

Research Project: CONSERVATION AND UTILIZATION OF SUBTROPICAL/TROPICAL FRUIT CROPS, SUGARCANE, AND TRIPSACUM GENETIC RESOURCES Title: Application of Propiconazole in Management of Laurel Wilt Disease in Avocado (Persea Americana MILL.) Trees

Authors
item Ayala-Silva, Tomas
item Schnell Ii, Raymond
item Gordon, Garry
item Winterstein, Michael

Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 31, 2011
Publication Date: May 31, 2012
Citation: Ayala Silva, T., Schnell Ii, R.J., Gordon, G.G., Winterstein, M.C. 2012. APPLICATION OF PROPICONAZOLE IN MANAGEMENT OF LAUREL WILT DISEASE IN AVOCADO (Persea americana Mill.) TREES. Acta Horticulturae. 948:71-78.

Interpretive Summary: Laurel wilt is a vascular disease of Lauraceous plants caused by a fungus (Raffaelea spp.) that is carried by a recently introduced, nonnative ambrosia beetle (Xyleborus glabratus). The disease is devastating to Persea species including redbay (Persea borbonia) and avocado (Persea americana) trees in forests, parks, orchards and residential areas in the southeastern United States. Avocado, is the most important agricultural crop susceptible to laurel wilt. Management strategies for reducing its impact in Persea sp (specifically P. americana) are needed. The USDA ARS NPGS collection of avocado is maintained at the National Germplasm Repository (NGR) in Miami-Dade County Florida. At the present time the avocado collection is now free from the ambrosia beetle and the laurel wilt disease, it is beleive that insect/disease will reach the collection. Infusion of the fungicide Propiconazole (Alamo) has demonstatted to control the disease in Persea and other oak species. In this study, the use of the fungicide propiconazole (Alamo) injection through the root system was applied at the recommended doses. Plants were injected in June 2009 and again in February 2011. The rate of application was based on the diameter of the trunk at breast level (dbl). The rates recommended on the Alamo label with some modification were used. Results from research conducted in other Persea species suggest that propiconazole could be useful in preventing laurel wilt in avocado. Preliminary results demonstrated that propiconazole was present in trees injected 14 months after treatment.

Technical Abstract: Laurel wilt is a vascular disease of Lauraceous plants caused by a fungus (Raffaelea spp.) that is carried by a recently introduced, nonnative ambrosia beetle (Xyleborus glabratus). The disease is devastating to Persea species including redbay (Persea borbonia) and avocado (Persea americana) trees in forests, parks, orchards and residential areas in the southeastern United States. Avocado, is the most important agricultural crop susceptible to laurel wilt. Management strategies for reducing its impact in Persea sp (specifically P. americana) are needed. The USDA ARS NPGS collection of avocado is conserved at the National Germplasm Repository (NGR) in Miami-Dade County Florida. Although the avocado collection is currently free from the ambrosia beetle and the laurel wilt disease, it is believed to be only a matter of time before this insect/disease complex reaches the collection. Macro infusion of the fungicide Propiconazole (Alamo) has been shown to control the disease in red bay and other oak species. In this study, the use of the systemic fungicide propiconazole (Alamo) macro infusion through the root system was infused at the recommended doses. Plants were infused in June 2009 and again in February 2011. The rate of application varied greatly with the diameter of tree trunk at breast level (dbl). The rates recommended on the Alamo label were the rates use initially. Results from research conducted in redbay suggest that propiconazole could be useful in preventing laurel wilt in redbay and other Persea species. Preliminary results demonstrated that propiconazole was present in branches of trees injected 14 months after treatment.

Last Modified: 12/18/2014
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