WESLACO — Experts are on the lookout in the Lower Rio Grande Valley for two species of weevils capable of killing palm trees, according to Dr. Raul Villanueva, an entomologist at the Texas AgriLife Research and Extension Center at Weslaco.
“We’re currently conducting a Valley-wide survey for the red palm weevil and the South American palm weevil, both of which get into the crown of palm trees and move into the trunk, consuming internal tissue as they go,” Villanueva said.
They also reproduce along the way.
“Females can lay up to 200 eggs and as they hatch they also burrow into the trunk,” he said.
Affected palm trees can develop secondary infections, increasing damage and finally causing the tree to die, Villanueva said.
There is no insecticide or cure to control the insects or the damage they do, and since the pests are not native to this area, they have no natural enemies here to keep their populations in check, he said.
“So far, we don’t have any confirmation that they have made their way to Texas, but these insects are on the move and could easily find their way here,” Villanueva said.
Both weevils are relatively large, about an inch and a half long. The red palm weevil has a bright red color, while the South American palm weevil is black, he said.
“The red palm weevil originated in South Asia and has been found in two Caribbean islands, and in July it was detected in California. The South American palm weevil originated in Central and South America and moved into Mexico. It also has been reported in California.”
The movement of the weevils likely occurs when people move trees from one area to another, so Villanueva has two requests of the public.
“First, don’t bring palm trees from outside the area,” he said. “And second, don’t mess with the traps we’ve set out to survey for these weevils.”
The traps are hard to miss. They consist of white, 5-gallon buckets strapped to palm trees along major highways, Villanueva said.
“We’ve set up 41 traps along State Highways 83, 77, 281 and 100 near South Padre Island,” he said. “We also have traps on palm trees near several international bridges. We’re asking the public to please not tamper with these traps. These weevils could cause a major problem for our area and we need to know if and when we get them.”
The bucket traps were designed in countries where the weevils are a problem, Villanueva said. They contain an aggregation pheromone specific to the weevils as well as a mixture of antifreeze and water, a sugar-based solution to attract the pests and keep them from escaping the buckets.
“We check each trap every two weeks,” he said.
Villanueva makes the initial identification of the trapped insects. If he suspects any of being the palm weevils, they are sent to a U.S. Department of Agriculture lab in Maryland for positive identification.
USDA’s Animal Plant Health Inspection Service would be in charge of an eradication program if weevils are found, Villanueva said.
“Palm trees play such a huge role in our landscaping and in our area identity here that these two insects could cause major problems for us,” he said. “But residents can help by not bringing any palm trees from outside the area and by respecting traps.”
The bucket traps are placed only 3 feet off the ground because that’s the level the weevils fly. Once they land on a palm tree, they walk up to the crown, he said.
“Neither weevil is a great flier, so hopefully any palm weevils that might be out there will be lured into one of our bucket traps and not into the tree.”