University of California
Cooperative Extension Fresno County

Invasive Pest Watch


The alert home gardener can be one of the first lines of defense in detecting invasive pests trying to establish themselves in our diverse agricultural valley. The amount of projected lost revenue if these species become established is staggering.

6 Things You Can Do

What are invasive and exotic species?

Exotic species are organisms (plants, animals, and microorganisms) that are not native to a particular region. The impact of exotic pests varies considerably depending on the species and the area being invaded.

Some exotic species have been intentionally introduced to California, while others come in accidentally. Some species are able to rapidly colonize an area and become serious pests, often because they are no longer under control of predators or diseases that limited their numbers in their native habitat. Species that rapidly colonize an area are often called exotic invasives.

Once established, invasive species are extremely difficult to eradicate and can cause not only ecological disruption, but economic problems as well. Everyone has a part to play to keep exotic and invasive species from coming into California and spreading throughout the state.

Exotic and invasive pests and diseases threaten California's agricultural, urban, and natural areas. They fall under the following categories:

Insects and other arthropods

Snails and Slugs

Plant diseases

Weeds and other unwanted plants

Aquatic invasives

Animal and Human Diseases

Vertebrate pests

Exotic and Invasive Pests Website

UC Master Gardener Tip Sheet 8369: Aquatic Gardens, Not Aquatic Pests:  How to Practice Responsible Water Gardening

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