In 2002, the Olive Pest Management District was formed to help combat olive fruit pests in Glenn County. In order to fund district activities, a Special Assessment of 7 cents per tree was levied on those residents and orchardists with 10 or more olive trees.
Olive Fruit Fly:
Historically, District efforts have been focused on the control of the olive fruit fly (Bactrocera oleae). Specifically, funds have been expended to detect and treat or abate neglected roadside olive trees and abandoned orchards that harbor the pest. Extensive trapping for both detection and control purposes have occurred throughout the county. In some cases, tree and/or orchard removal was funded and carried out by the District. More recently, as the need for tree and orchard removal has decreased, so has the Special Assessment fee; it is now 2 cents per tree with a 100 tree per acre maximum.
The olive fruit fly is a very serious pest of commercial olives in California. The first reported find in California occurred in 1998. Since then, this pest has established itself in the olive growing regions throughout California. The larvae aggressively feed on the flesh of the olive, providing a point of entry for 
bacteria and fungi to colonize. Once compromised, the fruit begins to deteriorate and becomes unmarketable. The olive fruit fly is able to produce several generations per year and can thus easily infest every olive on a tree within a season. With a low threshold of tolerance for infested fruit, processors (table and oil) simply reject infested fruit and the grower is left to deal with the loss.
