Prepare to battle those fall bugs now

At the Fair Oaks Horticulture Center's Herb Garden,

 the sweet alyssum was on its way out and now it's gone. 

(Photo: Kathy Morrison)

Bagrada bugs and other nasties can sneak into gardens

By Kathy Morrison

Sweet alyssum produces a lovely cloud of white blossoms in any flower bed. In the Herb Garden of the Fair Oaks Horticulture Center this summer, it surrounded a beautiful 'Golden' pineapple sage.

That latter sentence is past tense because this morning I pulled out all the alyssum in the container, as well as the two clumps that were growing in a raised bed nearby.

Why yank them out? Well, it's getting to be fall planting season, and soon the FOHC's Vegetable Garden crew will be planting their brassicas -- cool-weather cole crops that include cauliflower, cabbage, kale, turnips and mustard greens. Alyssum also is part of that family.

You know which pest is attracted to brassicas? The bagrada bug, a nasty stink bug that was first seen in Southern California about 2008 and has spread north since.

The alert to the Herb group went out from master gardener/vegetable expert Gail Pothour -- she'd been checking around and under our lush alyssum for offenders. So far she'd only seen harlequin bugs (more about those in a minute) but the concern was there.

So there's no point making the vegetable gardeners' job harder: Out went the alyssum.

Those of us who mostly grow summer vegetables are accustomed to battling aphids, tomato hornworms, spider mites and leaf-footed bugs. But even though the weather's still very warm, fall planting plans have to include prevention of the pests of cool-weather crops.

Bagrada bugs are only 1/4-inch long; the female

is larger than the male. (Courtesy UC IPM)

Note this sentence from UC IPM's page on bagrada bugs: "Even though Bagrada bugs prefer cool-season cole crops, their development is favored by warmer temperatures." Bagradas will feed on stems, leaves, flowers and seeds, UC IPM says, and are "particularly damaging to small plants and may kill seedlings."

In addition to monitoring or removing potential host plants, including weeds, the gardeners also put floating row covers on hoops over the vegetable seedlings. This is to deter those little butterflies you see in the fall from laying eggs on the plants. Those eggs grow into cabbageworms (white butterflies) and cabbage loopers (brown moths), which will skeletonize the leaves given the chance.

The harlequin bug is 3/8-inch long and is brightly colored.
 (Courtesy UC IPM) 

Harlequin bugs, by the way, often are confused with bagrada bugs, UC IPM notes. But harlequin bugs are larger. They are piercing-sucking pests, too, but have some natural predators that contribute to control.

If you find bagrada, harlequin or other stink bugs in the garden, handpicking is the easiest way to handle them. Don't squish them -- there's a reason they're called stink bugs. Instead, knock them into a bucket of soapy water.  And keep a close watch for additional invaders; they can multiply quickly. Your fall and winter crops depend on your vigilance.