It's time for apple and pear tree owners in Davis County to begin spraying their trees to fend off codling moths.
The moths, a long-time Utah pest whose larvae plague fruit by feasting on seeds, can be stymied by chemically spraying for them between May 24 and June 13.
That's when the most eggs will hatch, says JayDee Gunnell, the Utah State University Extension horticulturist in Davis County, because nighttime temperatures are around 55 to 60 degrees.
Ideally, residents could have started spraying Wednesday for the first emerging moths.
A second generation of codling moths will begin to emerge in early July, with peak activity in mid-July and August.
"The first generation is most crucial," Gunnell said, adding that apple and pear tree owners need to protect their trees until harvest, usually in mid to late summer.
"If left unchecked, these pesky critters may cause drastic fruit loss as well as innumerable dry heaves as unsuspecting consumers discover their presence one bite too late," according to a news release from Gunnell's office.
Gunnell said the spray chemicals can be obtained at any local nursery. Common chemicals include Bacillus thuringiensis, Spinosad, Carbaryl, Permethrin and Malathion.
Larvae normally enter fruit from the bottom, but may also enter where two fruits touch.
Thinning fruit so there are 5 to 6 inches between them helps keep side entries down, Gunnell said.
Gunnell said he doesn't know how many pear or apple tree owners there are in Davis County, but the most common question his office gets is, "When is it time to spray?"
More information about spray timings, as well as a pest advisory that is updated every week, is available online at utahpests.usu.edu/ipm and click on the "Pest Advisories" link.
Residents can also contact their local USU Extension office to determine a spray time for their specific areas.
E-mail: jdougherty@desnews.com