Peaches. (Photo by _Alicja_/Pixabay)

Agricultural officials in eastern Contra Costa County are planning an eradication effort and an extensive pest survey after the detection of an insect that threatens the region’s crops and other natural resources.

The peach fruit fly, also known as bactrocera zonata, was discovered in the areas of Brentwood and Oakley between July 31 and Aug. 14.

So far there are only three residences affected in Contra Costa County, but other specimens have been detected in Alameda and Santa Clara counties.

A peach fruit fly. (Photo by Curtis Takahashi, California Department of Food and Agriculture)

These particular pests were discovered as part of Contra Costa County’s coordinated pest prevention system, which now calls for traps to be placed in concentric circles going out roughly 4.5 miles in each direction from every location where the flies have been found.

If more peach fruit flies are found in that survey, that might trigger an agricultural quarantine. These pests are most commonly spread by “hitchhiking” in fruits and vegetables illegally transported by travelers coming back from infested regions.

According to the state Department of Food and Agriculture, the peach fruit fly (or PFF) is usually five to six millimeters in length. It has a reddish-brown body with yellow patches on the thorax and two black spots on the face. The wings are transparent and have a small brown spot at the tip.

It is believed to have originated in Asia, but was also accidentally introduced into North Africa. The fly damages fruit and vegetable crops when the female lays eggs inside fruit. Those eggs hatch into maggots, which tunnel through the fruit and ruin it.

The invasive insects affect a number of crops produced in the area, like tomatoes. Contra Costa County farmers harvested more than 209,000 tons of tomatoes in 2017, valued at roughly $23.4 million, according to a report from the Contra Costa County Department of Agriculture.

It also attacks apricots, peaches and pomegranates, all of which are grown in Contra Costa, though the crops are considerably smaller and have less economic impact on the county’s growers.

Outside of Contra Costa County, the peach fruit fly also threatens apples, avocados, citrus, cucumber, dates, figs and pears – all of which are important crops around the state.

For more information, call the exotic pests hotline at 800-491-1899.