Debbie Arrington

Seeds: Look out, stink bugs are back

Brown marmorated stink bugs gather on a tree branch in midtown Sacramento in September 2013.
Brown marmorated stink bugs gather on a tree branch in midtown Sacramento in September 2013. UC Davis

It’s almost summertime and bugs are getting busy. Pests that disappeared in November are coming out of hiding, ready to start another attack.

For Sacramento gardeners, new threats are literally popping out of the woodwork. Brown marmorated stink bugs, the bane of midtown, hibernate any place they can squeeze, which includes the tiny spaces around a house’s trim and siding.

“We found them under downspouts and around windows,” said Chuck Ingels, the UC Cooperative Extension’s farm and horticulture adviser for Sacramento and Yolo counties. “Lift up a piece of bark (on a tree), and you’ll find them. They can survive down to 20 degrees.”

As soon as they come out of hibernation, they’re ready for action – and laying eggs. By September, their population will spike and so will their damage.

Brown marmorated stink bugs had been unknown in Sacramento just two years ago. A swarm on a Chinese pistache tree at 13th and R streets in 2013 was the first official sighting of this invader in Northern California.

“When I saw the photo (taken by the tree’s perplexed owner), I recognized it right away,” entomologist Baldo Villegas said of the shield-shaped bugs that stumped other local experts “I got the address and started checking. I found it all throughout the area.”

This bad bug already is well-established in Los Angeles County and can now be found in seven counties, Ingels noted. “The writing was on the wall. It’s here now, and we can’t stop it.”

Originally from Asia, these stinkers – which truly emit an awful odor when squished – have few enemies in the United States. Since the first confirmed sighting in Pennsylvania in 2001, brown marmorated stink bugs have been found in 41 states. They feed on at least 300 species of plants, sucking the juice out of fruit and vegetables, turning well-rounded healthy tomatoes, peaches and apricots into unappetizing deflated bags of mush.

“It’s a really severe problem in the mid-Atlantic states,” Ingels said. “We first saw it in California in 2006 in San Marino and Pasadena.”

To monitor the BMSB spread, Ingels set up special 4-foot-tall pheromone stink bug traps in several locations and carefully monitors their catch. Since that first sighting, these dreaded bugs have been found from Yuba City and Citrus Heights to West Sacramento and Stockton. In December, the first BMSB were found in San Jose.

“They’re hitchhikers,” Ingels said. “They latch onto your clothes or your car. That’s how they travel.”

Sacramento’s stink bug population seemed to decline last fall, but it may have been an illusion.

“I found them in every street tree for three blocks along R Street,” Villegas said of his own bug check.

Stink bugs are particularly attracted to Tree of Heaven (Ailanthus altissima), Ingels said. “That’s their absolute favorite.”

Gardeners in Fremont Community Garden, ground zero for the original BMSB invasion, are fighting back with trap crops. Clusters of sunflowers and sorghum – two plants that stink bugs prefer for egg laying – have been positioned in strategic locations around the garden at 14th and Q streets. When stink bugs are spotted on sunflower leaves, they can be sucked up with a hand-held vacuum or caught by hand.

“That’s one thing in people’s favor – these stink bugs are slow,” Ingels said. “The (young) nymphs can’t fly, although they can scramble in a hurry. The adults can fly, but won’t unless it’s warmer than 70 degrees.”

41States that now have brown marmorated stink bugs

Bug hunters should go BMSB-looking early in the morning; that’s when they’re easiest to catch. Knock or drop them into soapy water, and they die on contact.

They’re also attracted to bright light, Ingels noted. One of the most effective traps also is among the simplest: A bright light aimed at a shiny aluminum pan filled with sudsy water. At night, the stink bugs follow the light right into their death pool.

Researchers and gardeners nationwide are looking for a solution. Tests on a parasitic wasp may give gardeners a beneficial insect to help in their buggy battle before BMSB populations become overwhelming.

Funded by the USDA, a team of researchers is devoted to stopping BMSB. Their work as well as videos and stink bug-fighting tips can be found at Gardeners can find out the latest and add their own sightings.

Ingels maintains a local map of specific sightings and details. The UC Cooperative Extension also offers updated advice.

Catching (and drowning) these bad bugs early can help limit their potential damage. As summer weather warms, expect to see more of these unwanted pests – especially in midtown or downtown Sacramemto. Just don’t let them hitch a ride to somewhere else.