Red imported fire ant (RIFA), Solenopsis invicta, has been reported as a pest in Florida where the fire ants girdle young citrus trees (Diepenbrock) https://crec.ifas.ufl.edu/media/crecifasufledu/extension/extension-publications/2021/2021_jan_fireant.pdf Florida researchers found that RIFA girdled the trees and killed them. In the summer of 2022, we discovered newly planted avocado trees being girdled and killed in WHERE?. Upon closer examination we discovered the girdling was from the activities of a fire ant. Dr. Dong-Hwan Choe, Professor of Extension – Entomologist at UC Riverside, identified it as Solenopsis sp. Figure 1 show the initial damage to an otherwise healthy avocado tree which weeks later was completely girdled and dead. Fire ants were controlled using a bait. This took 2 applications. Fire ant mound is evident in Figure 1B but is not the typical mound that is associated with fire ants so growers need to be watching for ant activity and treat proactively. The fire ants were very aggressive to both the tree and the people working the trees.
Figure 1: (A) initial holes made by fire ants. (B) girdled tree and mounds at basin of tree and (C) dead trees.
