A fleet of aerial spray planes began massing in 10 eastern Wyoming counties last week as part of a program aimed at minimizing the damage to forage crops likely to be caused by an anticipated massive hatch of grasshoppers this spring.

“This is something you’re likely to see once in a lifetime,” says Dean McClain, owner of Ag Flyers Inc. in Torrington, WY. He’s helping coordinate efforts to bring in eight airplanes from companies located as far away as Indiana and Texas to battle the hoppers. Officials from other parts of the state could bring in another 15 or so planes. “There are only three or four aerial spray application businesses in the state.”

The game plan is for the planes to spray the insecticide Dimilin mixed with canola oil on private and government-owned grasslands and rangelands in the 10-county area. The goal is to kill off grasshoppers in the nymph stage before they morph into more destructive, mature insects.

“There are 104 species of grasshoppers in Wyoming, but only 12 that cause damage,” McClain says. “It’s that ‘dirty dozen’ we’re really after.”

He adds that, even in the nymph stage, grasshoppers can consume tremendous amounts of forage. “At a population of eight per square yard, they’ll eat as much as an adult beef cow,” he says.

Plans for the aerial spraying project began to take shape earlier this year after USDA’s Animal and Plant Health Inspection Service (APHIS) released a report warning that Wyoming and several other Western states could experience severe grasshopper infestations in 2010. As we reported in the April 13 edition of eHay Weekly, the APHIS warning was based on a fall 2009 survey of grasshopper populations. The report showed adult grasshopper populations in Wyoming exceeded 15/sq yd on 2.9 million acres last fall.

McClain notes that spraying got under way in two counties last week and will likely begin in at least three other counties this week. Spraying will continue through the end of June.