RENO, Nev. (AP) -- State forestry officials are trying to determine why a pinhead-sized insect has infested an estimated million acres of pinyon pine forests across much of Nevada.
The outbreak has grown dramatically from an estimated 200,000 acres of public and private forests a year ago, said Gail Durham, a forest health specialist with the Nevada Division of Forestry.
Aerial surveys this summer found evidence of the infestation over about 1 million acres, or 1,500 square miles -- an area equal to the size of the state of Delaware, she said.
The bugs called "pinyon needle scale" suck sap from pine needles. Smaller trees can be killed and larger ones weakened to the point they are vulnerable to bark beetle attacks.
"The scale is getting worse," Durham told the Reno Gazette-Journal. "It's all throughout the state."
The surveys found the insects from the Spring Mountains near Las Vegas to the hills near Ely and Pioche, and the slopes above Topaz Lake on the California line south of Carson City. They prefer pinyon pine forests between altitudes of 5,200 feet and 6,000 feet.
Durham doesn't know what's causing the outbreak of how it compares with previous ones. Previous infestations occurred in Nevada during the 1950s and 1960s.
"We know we had outbreaks before, but there's no data on how bad it was and how long it lasted," Durham said.
Melinda Cash said it wasn't until she attended a meeting of the Nevada Fire Safe council last summer that she learned what was happening to her pinyon pines on her property in Mound House just east of Carson City. She said her trees looked sick and scraggly, with branches devoid of needles.
"You can see right through them. Usually you can't see through a pinyon," said Cash, 56. "I have a lot of trees dying with their needles falling off. It's crazy."
Insecticide can be used against scales in the spring. In the winter, when scales are dormant, pinyons can be sprayed with an oil solution that causes the insects to suffocate and fall dead from the trees.
The oil solution will be used on some of Cash's trees in January, but state funding to assist private landowners with the problem is limited, Durham said.
In the meantime, the problem faced by Nevada's pinyons is clear to see.
"They look like ghosts of their former selves," Durham said.
Information from: Reno Gazette-Journal, http://www.rgj.com
Copyright 2010 The AP.