Malathion Spraying for Medfly Set in San Bernardino County

Agriculture officials will shower a 15-square-mile area of Rancho Cucamonga and Upland with malathion later this week after the discovery of San Bernardino County’s first fertile Mediterranean fruit fly.

Gov. George Deukmejian on Tuesday signed documents declaring a state of emergency in the county and paving the way for four hours of aerial spraying beginning at 9:30 p.m. Thursday.

“We don’t want to take risks and let this develop into a major infestation,” county Agricultural Commissioner Edouard Layaye said. At stake, he said, is the county’s valencia and navel orange crop, which produces gross revenues of $20 million annually.

A female Medfly bearing well-developed eggs was found Friday in an insect trap in an orange tree at a home on Lomita Street in Rancho Cucamonga. That trap was one of 4,000 scattered throughout the county and monitored regularly by officials on the lookout for the insects.

County officials quickly sprayed malathion from the ground in a 1,000-yard radius around the tree where the fly was found, Layaye said. Another 1,100 traps also were set, but daily checks have turned up no additional flies.

The Medfly is viewed as the most destructive of fruit flies. Experts say the pest could cause yearly losses of more than $205 million in crop damages statewide if it were to take hold.

Earlier this year, three adult Medflies were found in Los Angeles County, prompting officials there to spray neighborhoods north of downtown Los Angeles and declare a 70-square-mile quarantine zone.

The area to be sprayed is bordered by Euclid Avenue on the west, Arrow Highway on the south, Turner Avenue on the east and Hillside Road on the north. Ten days after the spraying, officials will begin releasing 10 million sterile Medflies each week until the colony perishes from an inability to reproduce.