An overview of California's biggest agricultural threat as envisioned by members of the California Invasive Species Advisory Committee. Invasive Species Council of California.
Preventing the Introduction & Establishment of Invasive Species is Always the Best -- and Least Costly -- Method of Control.
One of the primary mandates of the California Department of Food and Agriculture is to "Protect against invasion of exotic pests and diseases." [CDFA Mission Statement] California agricultural losses to exotic pests exceed $3 billion annually (Source: Center for Invasive Species Research, U.C, Riverside).
So exactly what ARE invasive and exotic pests (and diseases)?
- Exotic pests are organisms that are introduced into an area beyond their natural range and become pests in the new environment. They are also referred to as alien, non-native, or introduced pests.
- Most introductions have been unintentional and accidental. Having evolved in a different ecosystem, these non-native species may have few natural enemies in their new locations, which can often lead to population increases that can overwhelm native species by out-competing them for resources (e.g., food, water, light, space).
- An invasive species is a species that does not occur naturally in a specific area and whose introduction does or is likely to cause economic (including agricultural) or environmental harm or harm to human health.
- Official U.S. definitions regarding invasive species were provided in 1999's Executive Order 13112. "Invasive species" means an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health. "Alien species" means, with respect to a particular ecosystem, any species, including its seeds, eggs, spores, or other biological material capable of propagating that species, that is not native to that ecosystem. "Ecosystem" means the complex of a community of organisms and its environment.
- Common traits of invasive pests and pathogens include rapid reproduction, fast growth, wide dispersal, altering of growth or form to suit a particular habitat, tolerating a wide range of environmental conditions and the ability to feed on a variety of different foods.
- All species have vectors that can move them to new areas to colonize, but for invasive species it's usually human activity of some kind (such as foreign trade and travel) that has transported them here unknowingly. Often the best single predictor of invasive ability is whether a species is already known to be an invasive pest somewhere else.