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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Insects and Horticulture Research » Research » Publications at this Location » Publication #313867

Research Project: IPM TECHNOLOGIES FOR INSECT PESTS OF ORCHARD CROPS

Location: Subtropical Insects and Horticulture Research

Title: Laurel wilt in avocado: Review of an emerging disease

Author
item Pisani, Cristina - University Of Florida
item Ploetz, Randy - University Of Florida
item Stover, Ed
item Ritenour, Mark - University Of Florida
item Scully, Brian

Submitted to: International Journal of Plant Biology and Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2015
Publication Date: 8/25/2015
Citation: Pisani, C., Ploetz, R., Stover, E., Ritenour, M., Scully, B. 2015. Laurel wilt in avocado: Review of an emerging disease. International Journal of Plant Biology and Research. 3(3):1043-1049.

Interpretive Summary: Laurel wilt affects avocado and many related trees and is caused by a fungus that is transmitted by the redbay ambrosia beetle. The fungus and beetle are native to Asia and were accidentally introduced into the United States around 2002 through infested shipping material in Georgia. The beetle and disease have spread and now have moved progressively into and down Florida, arriving in the commercial avocado production area of Dade County in 2011. The immediate threat to avocado production and the possibility of spread to other states has made identification of control measures a high priority. Current research has identified fungicides that are effective but expensive, and some beetle-attacking fungi show promise for control of the beetle. However, use of resistant avocado cultivars would provide the most sustainable long-term solution and is thus being pursued.

Technical Abstract: aurel wilt, caused by the vascular fungus Raffaelea lauricola, is transmitted by the redbay ambrosia beetle, Xyleborus glabratus, and affects many plants in the family Lauraceae. It was introduced into the United States around 2002 through infested packing material arriving in Georgia. In Florida, the beetle and disease have moved progressively down the state, arriving in the commercial avocado production area of Miami Dade County in 2011. The fungus grows in galleries and adjacent sapwood of host trees, leading to the disruption of water and nutrient flows. Symptoms include streaks of black discoloration in the sapwood with beetle bore holes on stems and branches of affected trees. Wilt symptoms are associated with the production of gels and tyloses in infected trees. The immediate threat to avocado production in South Florida and the possibility of spread to other states has made identification of control measures a high priority. Current research is testing new fungicides, and different strains of entomopathogenic fungi are showing some efficacy against the redbay ambrosia beetle. However, use of resistant avocado cultivars would provide the most sustainable long-term solution. As such, screening of the germplasm by artificial inoculation with the R. lauricola pathogen in the field is under way and protocols to facilitate higher throughput screening are also in development. It is hoped that promising laurel wilt resistant selections with excellent horticultural traits and fruit quality for commercial production will be identified.