Larvacides -  Chemicals used to control immature (larval) mosquitoes are called larvacides.

The Glenn County Mosquito & Vector Control District (GCMVCD) use many different methods to control mosquitoes while they're still in their larval stage. Larvaciding is the preferred method of mosquito control because you eliminate mosquito larvae before they mature into adult mosquitoes and become a nuisance or a possible public health threat.

GCMVCD Staff spends most of the day inspecting and treating potential mosquito development sites (sources) within the Service District boundaries. These inspections may occur in rice fields, wetlands, pastures, ditches, storm drains, catch basins/return systems, residential sources and various other man made sources where standing water is present. 

GCMVCD staff take many factors into consideration before choosing what control method is best for each larval source. These factors include but are not limited to:

• Mosquito species present
• Larval stage of development
• Pest, nuisance or disease potential
• Disease activity
• Mosquito abundance
• Flight range of mosquito
• Proximity to populated areas
• Size of source 
• Presence/absence of natural enemies or predators
• Presence of sensitive/endangered species or habitats

Control Methods

• Source Reduction
• Physical Control
• Biological Control
• Chemical Control
• Adult Control