Good News: Salt Cedars are Shedding Leaves, May Take More Years for Extermination

It was noticed that the salt cedar along the waterways of the southern and eastern Panhandle were getting leafless and dying at a faster rate. And an entomologist from Texas A & M AgriLife Research provided a reason for the process of defoliation.

Dr. Jerry Michels and his entomology crew in parts of Lake Meredith and the Palo Duro Canyon carried this study.

When in 2006 salt cedar beetles from Uzbekistan were released by Dr Michels team, it was assumed that the beetles would be more prolific eaters of salt cedar than other beetle species tried before.

"Salt cedar displaces native vegetation and impacts the availability of water," Michels said.

There were numerous projects conducted across the state in order to check if salt cedar beetles can help control the salt cedar along the infested waterways. If the beetles repeatedly defoliate the trees for several years, the salt cedar will die back and leave more water.

But the initial releases of beetles didn't take off and establish themselves immediately, for one reason or another, Michels said. They just never seemed to make it from one season to the next.

"However, we've had such a surprise this year," he said. "This species of beetle has exploded all across the area from Wichita Falls to north of the Canadian River on the eastern side of the Panhandle and all the way west into the Palo Duro Canyon."

Michel attributes this change to the weather.

"We had a hot summer and it warmed up earlier, so we think they came out earlier and began multiplying quicker," he said. "And we didn't have a late season freeze in the spring that typically kills off a bunch, so they had a chance to rapidly multiply."

Curing the 2006 release from Uzbekistan, the beetles suited to the climate at this latitude and longitude.

"We started getting calls about dying salt cedar in June and they just kept coming," he said. "We were happy with what we initially saw, and now we are just blown away when we are looking at the watersheds and river drainages -- we've found the defoliation every place we've gone."

According to Michel some more research is needed in order to determine what species the beetles are and track their path from the various release points. The team will track their movement to help better understand what helped them to thrive this year.

"Where these infestations originated is a bit unclear," he said. "We made releases of this species at Palo Duro Canyon in 2007. The Palo Duro Canyon study was flooded out. The cages were destroyed and we figured the beetles were carried downstream."

"The one thing that may give us a clue as to what and where the beetles came from is the work James Tracy, a doctorate student at Texas A&M University, is doing."

"We may be able to tell where the current beetles come from by looking at the amount and type of hybridization we see in the beetles we collect," he said.

According to him some of the beetles released have worked, while others didn't. And that, there has been some hybridization that is taking place through the years.

"These beetles come out every spring, but because many years have a late freeze, they have a hard time multiplying into effective numbers," he said.

"This year, it was warm early and there was rain and all the plants greened up and they had food and began mating early. With no freeze to kill them off, we ended up with several generations in one summer," Michels said.

They generally expect the salt cedar beetles to produce four generations each summer.

According to Michel it will take two to three years of defoliation to kill the trees completely.

"If after this year this wasn't enough of a population growth to keep them here permanently, then they will never establish," he said. "But I think we have enough that will over-winter and they will stay around."