These unwanted guests are real stinkers.
The midtown Sacramento invasion of brown marmorated stink bugs has both backyard gardeners and the Central Valley agricultural community on edge. BMSBs — also known as Halyomorpha halys — are voracious eaters with no local predators (yet) to keep them in check.
These stink bugs, native to Taiwan, aren’t picky eaters. They gobble up “apples, pears, cherries, peaches, melons, corn, tomatoes, peppers, berries, wine grapes — just about any plant with a botanical fruit — as well as many ornamentals, especially trees such as Paulownia, catalpa and Tree of Heaven,” said Chuck Ingels, horticulture adviser for Sacramento County’s UC Cooperative Extension.
“We saw a fig tree this morning and the fruit on the tree was completely shriveled,” Ingels added. “They feed directly on the fruit, but they feed on leaves, too. I found them all over Chinese pistache trees.”
Experts at the Cooperative Extension hope to have an online map up soon, charting locations of confirmed BMSB sightings. Gardeners will be able to access the map and add their own sightings at the extension’s website ( http://cesacramento.ucanr.edu/).
As of Monday, Sacramento’s stink bug zone was bordered roughly by O and Z streets between 11th and 17th streets. But later that day, two confirmed BSMBs were found sitting on a window air conditioner at 11th and D streets.
“Fremont Community Garden (at Q and 14th streets) is right at the epicenter of the problem,” Ingels noted. “So far, we’ve found (BMSBs) on tomatoes and beans in the garden. But they’re going to be a much bigger problem in the near future.”
Sacramento isn’t alone in stink bug territory. Three other BMSBs have been found in the city of Davis.
These bugs are strong fliers, too. They can travel a half-mile a day.
“It’s likely a matter of time before they reach farms – perhaps one to three years – and growers should be on the lookout for these true bugs,” Ingels warned.
Since the Sacramento stink bug outbreak came to light last week, Ingels has been scrambling to help local growers and gardeners. In October, stink bugs tend to aggregate in large numbers. They’re attracted to lights at night. In winter, they’ll squeeze into cracks around buildings and other protected spaces. Eaves are a favorite hiding place.
“If people suspect they’ve found one, the first thing to do is make a positive identification,” Ingels said. “It’s easy to confuse BMSB with other stink bugs. Ideally, put the bug in a tightly sealed plastic bag such as a Ziploc, or in a bottle with a good lid. Then, bring it to our office so we can document it.”
The UC Cooperative Extension office is at 4145 Branch Center Road in Sacramento. Call (916) 875-6913 for hours and directions.
Ingels noted that other pests formerly unknown here have recently invaded California. Those include the Asian citrus psyllid, which spreads Huanglongbing or citrus-greening disease. That incurable malady — which has devastated citrus orchards in Florida and South America — makes citrus trees bear bitter, misshapened fruit before killing the trees altogether.
Japanese beetles, a major lawn and garden pest elsewhere around the United States, keep popping up in Fair Oaks. A strain of downy mildew, considered extremely rare in Sacramento, wiped out local impatiens this spring.
“When will these new pests stop?” Ingels said.
Gardeners often unknowingly give these bad bugs a leg up on their march to new munching grounds. People need to know “how important it is for residents not to bring plants in from other states and countries,” Ingels said.
For example, researchers traced the California case of Huanglongbing to a single piece of infected budwood brought to Los Angeles from Asia and grafted onto a backyard citrus tree.
“People are really mobile these days,” Ingels said. “They travel around the world and bring back all sorts of things they shouldn’t, such as fruit, flowers and soil.”
International shipping also spreads these pests, which hitchhike on boats or containers.
“When these pests arrive here, they have no predators that keep them in check in their native countries,” Ingels said. “They come in predator-free.”
U.S. Department of Agriculture researchers are trying to find a way to stop BSMBs, which are widespread in several eastern states. Parasitic wasps, their natural enemy, have been imported from Asia but are in quarantine.
“It will be early 2016 before they’ll be ready for release,” Ingels said of the wasps. “They have to be studied for two to three years to make sure they don’t cause more problems than they solve. We don’t want them killing our beneficial insects.
“Parasitism is the best hope for reducing (BSMB) populations,” Ingels added. “Control of BMSB is very challenging. Some insecticides are effective but must be applied frequently, and sometimes they have simply not worked.”
Meanwhile, the best way to get rid of these stink bugs now is still the old-fashioned one.
“After you ID them, you can squish them or vacuum them up,” Ingels said. “But remember, they are stink bugs. They’ll stink when you squish them.”
Call The Bee’s Debbie Arrington, (916) 321-1075. Follow her on Twitter @debarrington.