Stanislaus County's walnut buying season began Nov. 4 and authorities are warning growers to be wary of thieves.

The walnut industry is particularly vulnerable to theft because of how the nut is harvested, according to Agricultural Commissioner Milton O'Haire.

Typically the walnuts are shaken from the trees and left unattended in windrows until they are collected by harvesting equipment. It's during this time that thieves can sweep into the orchards, collecting the walnuts and selling them illegally.

In an effort to curb the thefts, the Stanislaus County Board of Supervisors passed the Purchase and Sale of Walnuts ordinance, which has established a buying period and new requirements regarding the transportation and identification of walnut crops.

The buying period extends through April 30, 2015.

During the buying period non-processing walnut buying operations within the county may lawfully purchase and receive walnuts that have not been dried or processed.

Non-processing buyers must register with the Agricultural Commissioner's Office prior to commencing buying walnuts.

Any person selling less than 2,000 pounds of walnuts must possess a form of Proof of Ownership approved by the Commissioner at the time of sale. The form will include name, address, the source and weight of the nuts, and other information. A Proof of Ownership certificate may be obtained free of charge by contacting the Agricultural Commissioner's Office between 8 a.m. to 4:30 p.m. Monday through Friday.

Violators could face a fine and possible criminal charges.
Larger operations already have to provide ownership documentation.

Any person possessing walnuts which will not enter into commerce is exempted from the ordinance.

According to the Stanislaus County 2013 Crop Report, there were 37,435 harvested acres in the county with a value of $248 million.