Q:Β Our hopseed bushes suddenly had no leaves, and we think it is from leaf-cutter ants. We also noticed our palo verde tree near their mound has no leaves.Β Attached are pictures. There are a few mounds near the hopseed bushes and palo verde tree. We also just put in a brick paver driveway and are concerned that the ants will damage it. What should we do?
A:Β Leaf-cutting ants are often difficult to manage. Although plants can be protected temporarily using insecticides, they need to be reapplied frequently, and these chemicals kill other insects that may be beneficial or harmless. The best solution is to eliminate the underground nest. The nests may be very large, hard to find and difficult to mange with insecticides. Typically, underground ant nests are managed best with poison baits that the ants transport down below as food. Because these ants donβt eat the leaves directly, they do not respond to most ant baits you might find at your local hardware or grocery store. I believe Amdro Ant Block is currently the only widely available bait product labeled for control of leaf-cutting ants. Apply the bait according to label directions while ants are foraging. Ant activity in the treated colony will decline over a four- to six-week period. However, itβs possible the ant colony will survive and activity will return in four to six months, requiring a second treatment. Before using any pesticide, please be sure to read the label and follow all instructions and safety precautions to protect you and the other animals nearby.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Email questions to tucsongardensage@gmail.com
