Agri-dogs: Using Canines for Earlier Detection of Laurel Wilt Disease Affecting Avocado Trees in South Florida

Abstract

The invasive redbay ambrosia beetle (Xyleborus glabratus) was first detected in Savannah, GA, in 2002. This tiny beetle and its symbiotic fungal partner (Raffaelea lauricola) have led to one of the most devastating new plant diseases in recent times affecting laurel trees (Lauraceae), laurel wilt. In Florida, this devastating disease has also affected the agriculturally important avocado (Persea americana), and once symptoms are visible (i.e., wilting leaves), it is too late to save the infected tree. However, prophylactic systemic treatment with propiconazole can protect the trees from the disease for ≈12 months. This study evaluated the novel approach of using scent-discriminating canines (Canis familiaris) trained on the volatiles of laurel wilt pathogen as a proactive management tool for grove owners. Canine deployments in groves resulted in the detection of 265 presymptomatic avocado trees during two trials. In trial 1, 155 presymptomatic trees were treated with propiconazole and, over the subsequent 14-month monitoring period, 97% remained asymptomatic. In trial 2, the canines detected 100 presymptomatic trees that were not subsequently treated and 22 progressed to wilt within 2–5 weeks, and the remaining trees were removed, thus halting the observation period at 6 weeks. The canines have proven to be an effective proactive management tool.