Q: I’m concerned about the threat of the emerald ash borer in New Mexico. Should residents and cities be planting ash trees? Concerned Citizen of Otero County via County Agriculture Agent, Sid Gordon
A: The first step in dealing with what looks to be an imminent invasion of emerald ash borer (EAB) in New Mexico is educating ourselves on how this pest works, what to look for, and how to report anything suspicious.
Since 2002, when EAB was first identified in Michigan, it has killed or harmed hundreds of millions of ash trees in 31 states, including Colorado, Texas, Louisiana and Oklahoma. Many experts believe New Mexico could be next on the list. Scarier still, it could already be here and just not have been identified yet.
The EAB is a pretty, narrow-bodied, metallic green, wood-boring beetle that may cause minor foliar damage while in its adult stage, but the larvae feed on the inner bark (vascular system) of ash trees and are so aggressive that even healthy ash trees can die within two years.
Another scenario is that the EAB larvae kill an ash tree slowly, taking up to four years before symptoms are even visible. That information is from the Colorado State Forest Service, and they should know since the EAB was confirmed in Boulder in 2013.
What can and should we do about EAB risks in New Mexico? I checked with city parks experts from Santa Fe, Albuquerque and Las Cruces about their EAB concerns. I also interviewed NMSU Extension Agents from Bernalillo and Doña Ana counties, six nursery owners and managers from all over the state, and several state Department of Agriculture and State Forestry experts for recommendations. Here’s what they all agreed on:
1) Now is a good time to decrease new ash plantings and consider removing ash trees that are not performing well because those are likely more attractive to EAB than healthy trees. Provide existing ash trees with adequate irrigation. Examine ash trunks and major limbs for possible evidence of EAB infestation.
2) Ash trees have become too popular in our municipal and residential landscapes in New Mexico (and across the country), increasing the vulnerability to EAB attack. In order to diversify our tree populations, select native or adapted species that do well in your area.
3) Do not move firewood to or from another state – always buy local and burn it where you buy it.
NMSU Extension Entomologist and NMDA State Entomologist Dr. Carol Sutherland offers encouraging advice that can make an EAB scout out of all of us.
“Keep looking,” she says, “and take samples and photos of anything different or unusual occurring on your ash trees. … Photograph D-shaped emergence holes in ash tree bark, any increasing die-back in the canopy, and any peeling bark. Photograph loose bark from above and especially on the underside if you see any broad, flattened, winding tunnels. Promptly submit these photos plus your contact information to one of our many professionals who are trained and ready to help with the next steps.”
These trained professionals can be found at NMSU County Extension Offices (aces.nmsu.edu/county), the NMSU Plant Diagnostic Clinic (aces.nmsu.edu/ces/plantclinic), any of the six New Mexico State Forestry District Offices, or other State Forestry programs, including the Forest Health Program Office in Santa Fe. It’s important to get a positive EAB identification before cutting down trees.
Find information on how to identify an ash tree, lists of recommended trees for improved species diversification, and links to more EAB resources at nmsudesertblooms.blogspot.com.
Send questions to Marisa Y. Thompson, PhD, to desertblooms@ nmsu.edu, or the Desert Blooms Facebook page (@ NMDesertBlooms).