Going Buggy

The Rapid Movement of People and Goods Invites Exotic Pests to Hospitable Southland

Know that irritating little whitefly attacking garden plants, or the nasty fire ant threatening Southern California yards? And those pesky rules against transporting fruit and plants across state lines?

These problems have a common cause: imported pests. Known as exotic or invasive pests, they are nonnative species introduced from other parts of the world—often via vegetation transported by travelers or home gardeners.

Imported Pests: A Growing Problem

“We’re getting a large number of urban pests into the state and the country as a whole,” says Tim Paine, Chair of the Entomology Department at UC Riverside. “People are traveling a lot and moving a lot of plant material.”

Before blaming others, consider your own habits. That cutting from Aunt Mabel’s begonia you packed in your suitcase may seem harmless—but are you sure?

“We understand that people’s motives are good when they transport plants to remind them of a vacation, or fruit to give to family and friends,” Paine says. “But it only takes one pest. If 30 million people do it just once, it becomes a significant problem.”

Exotic Pests Can Be Dangerous

According to John Kabashima of the University of California Cooperative Extension, many exotic pests are hitchhikers or are being smuggled in intentionally or unknowingly.

“Even people aware that it’s illegal to smuggle fruit or plant material don’t understand the long-term fiscal, biological, and health consequences,” Kabashima says.

Some invasive pests—like the Africanized honeybee and the red imported fire ant—pose serious health threats and can lead to massive economic damage:

  • Formosan subterranean termite: Treatment of one home can exceed $5,000.
  • Mediterranean fruit fly: Control efforts have cost millions. If established, it could cost the state $1.4 billion annually.

There are also ecological impacts, including disruption of ecosystems and degradation of California’s cherished outdoor lifestyle.

Globalization Accelerates the Spread

Urban entomologist Michael Rust says exotic pests aren’t new, but modern transport has accelerated their arrival.

“The Argentine ant was first reported in California at the turn of the century. But insects that couldn’t survive a sea voyage 100 years ago now make it on a 12-hour flight.”

Entomology professor Paine adds:

“According to the California Department of Food and Agriculture, every 60 days on average a new insect pest is introduced or established. Some are harmless, others cause serious damage.”

Why Exotic Pests Thrive Here

Exotic pests thrive in Southern California due to:

  • Lack of natural predators and parasites
  • Mild Mediterranean climate
  • Extensive diversity of plant species in urban gardens
  • Regular irrigation and urban landscaping

“Urban landscapes rival tropical rainforests in plant diversity,” Paine notes. “Most gardens are well irrigated, creating ideal conditions for pests like the red imported fire ant, which wouldn’t survive here otherwise.”

Some exotic pests also crowd out native species, disrupting natural pollination, fertilization, and seed dispersal processes.

Controlling Exotic Pests: Past and Present

Past attempts to eradicate pests using herbicides and pesticides largely failed:

“After WWII, we believed chemicals could solve our insect problems. But pests returned, often stronger and pesticide-resistant. Meanwhile, beneficial insects were killed off and didn’t recover as easily,” says Rust.

Today, the preferred approach includes:

  • Minimal pesticide use: As a last resort only.
  • Biological control: Introducing natural predators to keep pest populations low, similar to their levels in native habitats.

“Biological control isn’t a quick fix, but it’s the only long-term solution,” says Paine. “You want to turn over a hibiscus leaf and find little to no whitefly.”

What Gardeners Can Do

While gardeners may not be scientists, they can help prevent pest spread by following these practices:

  • Resist the urge to smuggle fruit or plants.
  • Buy plants only from licensed California plant businesses.
  • Report unusual pests to:
    • Orange County Agricultural Commissioner: (714) 447-7100
    • California Department of Food and Agriculture: (800) 491-1899
  • Plant varieties suited for local conditions; choose resistant strains when possible.
  • Mix plant types in your garden—most pests prefer specific hosts.
  • Keep plants healthy with proper watering, fertilization, and pruning.

Julie Bawden-Davis

Julie Bawden-Davis is a bestselling journalist, novelist, blogger, and YouTuber. A prolific author, Julie writes in several genres. She enjoys creating page-turning suspense served up with a dose of romance, garden books that turn any brown thumb green, and spiritual books meant to enlighten and inspire. Widely published, Julie has written 45 books and more than 4,000 articles for a wide variety of national and international publications. She lives in Southern California, where she enjoys sunny, blue skies most days and year-round gardening. Julie gains inspiration from being surrounded by plants when she writes.