A Siberian insect infestation is putting the "bug" in "humbug" for some northern Utah County grain growers this holiday season.
The Russian wheat aphid, which primarily attacks grain plants, has found its target for the year: fall-planted wheat and barley crops throughout the northwest side of the county, especially in Cedar Fort, Cedar Valley, Fairfield and Lehi.According to USU Extension Services agricultural agent Dean Miner, the aphid has been in the state for nearly three years since being introduced in Texas six years ago.
The insect attacks grain crops by attaching itself to individual plants, Miner said. It then injects a toxin into the plant's leaves, causing them to roll up and encase the insect - effectively protecting it from non-systemic pesticide sprays (those that work on contact rather than being absorbed by the plant) and from predators, including ladybugs.
Among those Utahns who could be hardest hit are Lehi grain farmers Grant Smith and Steve Holbrook, who have more than 10,000 acres and 30 years of farming experience between them.
Holbrook, whose farm is actually between Lehi and Cedar Fort, said that aphid infestations have been an ongoing problem since the insect was introduced.
"It's been very frustrating, because (spraying before infestations) has been very hit and miss," Holbrook said. "Some years we've sprayed and there's been nothing, and then there are years like this one."
In some cases, the insects can cause as much as an 80 percent yield damage, because the plants receive no nutrients while their leaves are closed and the aphids then proceed to eat the crops.
Infested crops can turn purplish, with some white striping in severe cases, indicating that the plants may be dying, Miner said.
The wheat pests particularly prove to be a problem in the fall, because by the time telltale infestation signs have manifested themselves, temperatures have dropped below effective ranges for pesticides.
And because they came from Siberia, the aphids tend to survive even extremely cold temperatures very well.
"It's hard to say what kind of weather is going to encourage these infestations, which makes it even harder on the farmers," Miner said.
Holbrook, though, said he is optimistic that some fall spraying he and other farmers performed will have killed some of the insects, and that by spring, further spraying could minimalize the damage.
"We may be lucky when spring rolls around," Holbrook said. "Maybe we'll just have to see what's still there after the thaw."
Probably the only pesticide effective on the aphid is Disyston, which is absorbed through the plant's roots and then by the insect.
Miner said that farmers who are debating whether to spray should perform an accurate survey on their crops and that only those with 30 percent infestations or more should consider the option.