Catch those tough invasive species early

April 25 through May 1 is Invasive Species Awareness Week to promote local awareness and action to limit the impacts of invasive species. I'm most familiar with invasive plants, but there are also invasive animals and insects.

An invasive species is a non-native species whose introduction causes or is likely to cause harm economically, environmentally or to human health. Invasive species are very aggressive, growing and reproducing rapidly and causing problems to native habitats or species. This can mean reduced crop production and reduced fishing, hunting, camping, hiking or boating. Exotic invasive species cause $1.1 billion to $120 billion per year in economic losses. Approximately 42 percent of threatened or endangered species are at risk due to non-native invasive species (www.invasive.org).

Weeds are everyone's favorite thing to hate, so why all the concern with invasive ones? Invasive weeds survive and thrive outside their natural range, outcompeting native plants for nutrients, water and other resources, particularly on disturbed sites. Invasive plants spread quickly, decreasing forage for wildlife or livestock. Plants such as cheatgrass and medusahead also alter natural fire frequency, with more intense fires happening more frequently.

Some invasive plants are also known as "noxious" weeds. The term "noxious" is a legal definition for plants that have been determined to be major problems in agricultural and rangeland ecosystems. The federal government and many states, including Nevada, have lists of "noxious" plants. Some of the 47 noxious weeds on Nevada's list include yellow starthistle, Russian knapweed, hoary cress, perennial pepperweed (tall whitetop), puncture vine, Scotch thistle and salt cedar.

How can you help reduce the threat of invasive weeds? Learn to identify native and non-native plants in our area. University of Nevada Cooperative Extension has numerous weed publications on our website, www.unce.unr.edu, to help with this. Or, bring samples into our offices for help with identification.

The easiest and least expensive time to control or manage invasive weeds is during the early stages of growth and development. Because invasive plants are hardy and persistent, they can be difficult to control once established and often require years of treatment with herbicides to get them under control.

And, because they are aliens to Nevada, the insects that might eat the plants or the diseases that might control them are not present in our area. This means very little can slow them down, which is why it is so important to catch them early.

For more information on invasive or noxious weeds, call 887-2252 or email me at skellyj@unce.unr.edu.

• JoAnne Skelly is the Carson City/Storey County Extension educator for University of Nevada Cooperative Extension and may be reached at skellyj@unce.unr.edu or 887-2252.