Management and Control Techniques

We are fortunate in the Lake Tahoe Basin because we're in the relatively early stages of invasion by weeds. We have an opportunity to find and eradicate these plants before they become huge and expensive problems. The LTBWCG focuses on a technique called "early detection, rapid response" to nip infestations in the bud before they reproduce. However, we need your help in finding and controlling weeds on your own property. This web site will help you identify some of the worst invasive weeds, and below you'll find information to help you control them.

Before you pick a control method, be sure you have properly identified the plant in question. Take a sample to your county agriculture department, weed district, resource conservation or extension office to get help with identification. Or, email us at contact@tahoeinvasiveweeds.org. Once you've identified an invasive weed on your property, you'll be ready to determine the best control methods and timing for control. Effective weed control relies on selection of the most effective and affordable methods. The components of integrated weed management include physical (or mechanical), cultural, biological and chemical controls. Each has its place, and often we select several controls for a given weed species. Learn more about controlling specific invasive weeds.

Physical or mechanical control includes activities such as cutting, mowing, burning, mulching, pulling or cultivating that physically disrupt weed growth. Generally, this type of control requires a commitment of several years to succeed, due to regrowth from seeds stored in the soil or roots that can regenerate. When using mechanical controls, remember:

• Timing is important. Apply controls before full flowering so that viable seeds are not formed.
• Remove as much of the root as possible. Special digging bars or wrenches can aid in removing the root. Tools are available for loan, contact us for information on tools available in your area.
• Repeated cutting, mowing, or pulling (at least 3 times per season) is often needed to handle resprouts.

Cultural control relies on altering the environment where the weed is growing to make it unfavorable for its growth. In home landscapes it may be possible to alter watering schedules and amounts to make it more difficult for weeds to grow, and you may want to use mulches or geotextiles to prevent weed survival.

Biological control uses natural enemies, such as insects, to control the spread of noxious weeds. Biological control is generally used on weed infestations that are large enough to support the growth of the biocontrol agent. The majority of the infestations in the basin are not large enough to successfully use biological controls.

Chemical control involves the use of herbicides, or chemicals that kill plants. These products can be applied selectively and effectively when used properly. Herbicides are most often sprayed onto actively growing green vegetation. Consider the following before using chemical controls:

• Timing is very important.
• Good spray coverage of the entire plant is essential. Apply until the foliage is wet, but not dripping.
• If you want a specialist to treat your weeds, make sure that the pest control company is licensed and certified by the state.
• Always read the herbicide label carefully, and follow all directions.

Follow up is key! Once you've applied your control method(s), you still have some work to do. Check regularly for weed regrowth and treat again if necessary. Reestablish desirable plant species at the site to compete with the weeds and reduce soil erosion. A thick stand of healthy vegetation will help avoid future weed invasion.

If you still have questions after accessing the resources provided in this site, email us at contact@tahoeinvasiveweeds.org for further information and referral to your appropriate county contact.