With rain in the forecast for Thursday, Santa Clara County officials are postponing their scheduled larvicide operation against the winter salt marsh mosquitoes in the Palo Alto Baylands.

Initially scheduled for later this week, the helicopter operation in Palo Alto and near Alviso is now scheduled for Thursday, Feb. 23. The mission is to reduce the emergence of adult mosquitoes, which according to the district bite viciously and can fly about 15 miles from their breeding grounds in the marshes.

The treatment involves dropping a biological control agent and insect-growth regulator from helicopters at marshes in the county's coastal areas, including the ITT Marsh in Palo Alto and the Zanker Marsh near Alviso, according to the Santa Clara County Vector Control District.

In an announcement, the district stated that "current field conditions and mosquito growth trends indicate a high probability that a significant number of salt marsh mosquitoes will become adults in early to mid-March if left untreated."

More information about mosquito prevention is available at SCCvector.org. Residents can also call the district office at (408) 918-4770 or use the vector district's app, downloadable at SCCvector.org/app.