The Bagrada bug started stalking northward from Los Angeles County in 2008. Last year the insects entered the Salinas Valley, where they found a buffet of broccoli and cauliflower seedlings.

Broccoli brings $426 million dollars into Monterey County, with an additional $163 million stemming from cauliflower, according to the county’s 2013 Crop Report. To protect these cash crops, conventional farmers have turned to increased pesticide applications, while organic growers watch these pea-sized pests suck away their profits.

Cole crops are most susceptible to damage from the time they sprout until they are big enough to have grown four leaves. If the bugs feed on the top of the main shoot during this time, it can cause “multiple heads” to grow or “blind heads.” Using broccoli as an example, “multiple heads” result in many, tiny, unsellable broccoli heads; a “blind head” means no head of broccoli ever forms.

No one can say exactly how much money is being lost to the Bagrada bugs in Monterey County, but conventional growers are facing a 5 to 30 percent loss, reports Shimat Joseph, entomologist with the UC Cooperative Extension for Monterey, San Benito and Santa Cruz counties, on his Salinas Valley Agriculture blog.

The bugs also will slurp on tomato, pepper and potato plants, although their numbers are usually lower in these fields. Attacks on strawberries, lettuce, spinach or grapes have not been reported, Joseph said. Farmers have found the bugs scrambling over these plants, but they have not documented any plant damage.

Farmers had hoped the colder temperatures in Central California would limit the spread of the bugs, but they survived their first winter in Salinas Valley. All life stages of the bug – eggs, larvae and adults – have been found in Salinas Valley in February, which means they are reproducing year-round and not lying dormant over winter, Joseph said.

In Central California, their populations increase quickly in late summer with the warmer temperatures, but insects need food to sustain a large population.

Conventional farmers are applying insecticides at almost double the normal rate during the four to five weeks when seedlings are most vulnerable. Some growers are forced to spray two applications per week, Joseph said. The growers are staying within the limits for pesticide use, but they are basically spraying money onto their fields with each application.

Joseph suggests that growers may have better luck managing the Bagrada bug through techniques such as weed management.

Across organic farms, things are not looking good.

“For organic growers we don’t have any concert tools at this moment,” Joseph said. “They just take the loss.”

Source - http://www.freshplaza.com/