EL PASO, Texas -

Have you noticed?

El Paso's abundance of salt cedar trees is dying off. It's thanks to the release of salt cedar leaf beetles by entomologists back in 2006 along West Texas waterways.

They have now reached El Paso's Upper Valley. The hope is to eliminate salt cedar thickets that compete for water and reduce bio-diversity along the Rio Grande.

"It looks like this one is also dead and this one over here," Upper Valley resident Frank Dominguez told ABC-7 as he walked through his backyard, pointing over his rock wall to the dead salt cedar trees. "(I noticed) maybe the early part of this year. I hadn't noticed because I do remember when they were nice and green."

Salt cedar beetles were released eight years ago by the U.S. Department of Agriculture to combat salt cedar, known as the thirsty tree, along the Rio Grande.

"I guess the beetles have taken their toll over a period of time, because they didn't get this way overnight," Dominguez said, pointing to the trees.

In Sunland Park, near Western Playland and the banks of the Rio Grande, ABC-7 spotted a strip of salt cedar trees, which had seen better days. Entomologists say the control of salt cedar using beetles is one of the most successful examples of biological control of noxious plant species in the United States.

"The reason they want them to be gone is because they are drinking up all the water," said Ryan Black, who works at Casa Verde Nursery in West El Paso. "You can already see the decline down on Donipan. You can see they're all drying out from the bottom up, row after row. The whole street was dying. I think it's a very interesting concept what they're doing. It's biological control. I do agree it's much better than doing chemical, but at the same time who are we to judge a species life? But at the same time I guess it's good because it'll save us water."

A mature salt cedar can drink up to 200 gallons of water a day.

"My main concern is they are a fire hazard and since they're pretty full, that fire would be very hot," Dominguez said. "It presents a danger to those who have those trees in back of them."

Last year, some Upper Valley residents blamed dead salt cedars for fueling a huge wildfire in the area. ABC-7 was told land owners are responsible for the removal of dead salt cedar trees. But if residents want to keep their salt cedars and protect them from the beetles, entomologists recommend using insecticide.