Battle against bugs is essential for ag economy, health

Twenty-five-plus years ago, Imperial County farmers planted melons every fall and spring, making for a robust piece of the local ag puzzle.

Then the whitefly infestation hit, decimating the fall melon crop, and costing farmers about $250 million. The effect was such that fall melons are all but history.

Imperial County farmers and ag officials — as in most agricultural communities — have had an extensive history with battling invasive pest species to various degrees of success.

In the 1950s the community fought Khapra beetles, which wreaked havoc in grain stores around the county; so much so that Khapra beetle traps can still be found today due to how difficult it was to deal with the pest, Imperial County Agricultural Commissioner Connie Valenzuela said.

In that instance, Valenzuela said, the beetle was ultimately eradicated.

In other cases, it is not so easy to simply get rid of a pest; instead, it’s a matter of managing its advance and effect on the ag economy.

Today, county ag officials and farmers are in management mode against the Asian citrus psyllid, she said. The psyllid has been found throughout California and will not be eradicated, but so far the citrus-greening disease its infestation leads to has not been found here.

She said treatment in the cities and populated areas by county ag officials has controlled that portion, while farmers themselves police their orchards.

The recent discovery of a small pest never before seen in the United States stowed away in a truckload of produce from Mexico highlights the need for coordinated efforts between federal, state and local ag inspectors and growers themselves to protect the industry.

Agricultural specialists with U.S. Customs and Border Protection in Nogales, Ariz., found Claudinerobius slateri in a commercial shipment of celery March 20. Three days later, U.S. Department of Agriculture officials confirmed the species and the shipment was fumigated and released past the border.

“Stopping invasive species is really critical because a new species can cause millions of dollars of loss for agriculture,” Valenzuela said.

When a new pest is introduced into an area, she said, it comes without its natural counterpart — whatever native predator species keeps its population in check.

USDA inspectors working with Homeland Security identify potential threats to agriculture at the border and often it’s up to county ag and California Department of Food and Agriculture to monitor when that happens, Valenzuela said.

The communication between the state and county, however, seems to be better coordinated. According to Valenzuela, if a suspicious pest passes through the California-Arizona checkpoint, for one, inspectors will immediately notify the Ag Commissioner’s Office.

The county does have a multi-layered approach to dealing with its pests once they are discovered.

Valenzuela said the first step is a combination of quarantining and exclusion, or stopping the invasive pest at the border, be it state, county or international boundary.

The second would be proactive pest detection, she said, meaning inspectors would go out into the field and check traps, and not just for bugs, but for rodents. Part of that process is checking reports from the border, like that from Nogales.

The third level is eradication programs, which can take different forms, she said. That can include chemical agents or biological methods like introducing natural predators.

Alternatives, or a fourth level, if you will, can be turning over the eradication or management to the growers themselves if the county ag department can’t get rid of the pest, Valenzuela said.

The county might also take on biological control methods that don’t eradicate pests but neutralize their effects. Valenzuela cites the pink hibiscus mealy bug, where the county introduced a “parasitoid” from its native area that has controlled it.

Valenzuela said one of the biggest focuses of the county Ag Commissioner’s Office, and the department dedicated to it, is pest management.

“It’s a constant effort,” she said.

This story originally appeared in the Imperial Valley Press, April 2, 2015.