Weed and Pest Management

Yes, Longmont developed and updates an integrated weed management plan that directs staff activities and planning concerning the treatment of weeds on City property. That plan balances the requirement to eliminate noxious weeds and control nuisance weeds with goals to minimize the use of pesticides and protect valuable pollinator habitat. The City’s Integrated Weed Management Plan can be found here.

Yes, Longmont City Council passed a resolution recognizing the importance of protecting and supporting pollinators. The resolution includes goals such as minimizing pesticide use on City lands, eliminating the use of neonicotinoid-based pesticides except for cases where other treatment options don’t exist to protect valuable trees, protection of pollinator habitat, and so forth. The resolution can be read in its entirety here.

Relatively small amounts of glyphosate-based compounds are used in City parks. Most of these are small spot applications used to protect new young trees and shrubs from weed encroachment. Glyphosate is currently in the EPA’s re-registration process.

As mentioned before, any pesticide that is not used correctly by qualified persons can potentially impact non-target organisms such as pollinating insects. Most impacts of concern to pollinators come from large commercial operations and not typical municipal uses. Neonicotinoid (neonic) based pesticides are a classification of pesticides that are of specific concern for potential impacts to pollinating insects. Neonicotinoid pesticides have been used sparingly in recent years in Longmont and only for a few root and trunk injections to trees – they are not used in spray applications in City operations. Neonicotinoid based pesticides are currently in the EPA’s re-registration process.

A summary of spraying activities and locations can be found at bit.ly/weed-pest-management. This list is updated every time a treatment is planned.

A comprehensive list of the pesticides used in Longmont can be found at bit.ly/weed-pest-management. The list is updated monthly.

Cities use very small amounts of pesticides compared to commercial operations. In fact, residents treating their own lawns and shrubs in most cities likely use considerably more pesticides than municipal operations would when taken in total. Most municipal operations spot-spray small amounts of pesticides on single weed plants or small clusters of weeds with a fairly minimal amount of broadcast spraying from vehicles or backpack sprayers. Aerial techniques such as spraying from planes or from commercial irrigation systems that spray pesticides high into the air are not used in cities. Commercial operations can be of greater health concerns for non-target organism impacts because of the high volumes of pesticides used and the longer range delivery systems.

Pesticides or any chemical for that matter used around humans will most likely be controversial to someone – particularly chemicals that are used for food production or otherwise have the potential to be ingested (such as pharmaceuticals or plastic residuals from plastic bottles). The research evidence overwhelmingly supports that pesticides currently in use in the U.S. are safe when used according to the manufacturer instructions and for applications for which they are approved. Pesticides have been in use in the U.S. dating back to 1900. They are generally correlated with positive health outcomes such as the control of rodents and insects that carry disease, modern food production, and the reclamation of habitat that had been lost through natural and man-made disturbances. When used incorrectly they can present hazards. Industries and organizations that use pesticides in their businesses are in agreement that the pesticides should be used only when and where absolutely necessary and in the smallest effective amounts possible. The greatest concern is the impacts on non-target organisms when pesticides are used incorrectly and by unqualified persons. Most pesticide applications in parks and other public areas in Longmont are done during low use times and with advance and concurrent notification. Most pesticides emit an odor, and exposure to that odor does not indicate a negative exposure to pesticides.

Pesticides include both natural and synthetic formulations, but either type can present hazards to organisms or habitat if not used correctly. Pesticides are closely regulated via the Federal Insecticide and Rodenticide Act (FIFRA). The regulatory process for pesticides is similar to the Safe Drinking Water and Clean Water Acts and focuses on protecting human health and the environment. Pesticides are registered and re-registered on 15-year cycles. Pesticide registration requires that those seeking approval fund private and independent health studies to verify safety. Regulatory agencies such as the EPA and Center for Disease Control (CDC) also commission epidemiology studies for pesticides used in food production or for other widespread commercial purposes. Although no technology is entirely risk-free, pesticides are safe to use when applied according to the manufacturer’s instructions and by licensed pesticide applicators. Household pesticides are typically formulated in lower strengths for application by non-licensed persons, but by law, still must be used according to the instructions. Any person not using pesticides according to the label instructions is subject to fines and/or prosecution.

Weed control is generally achieved through multiple control methods including prevention via proper cultivation, removal using mechanical techniques, and prevention or eradication using pesticides depending on the application. Mechanical methods include mowing, tilling, hand pulling, steam treatment, and other similar techniques. Some mechanical methods such as mowing only delay the onset of weeds because seeds and roots aren’t removed. Mechanical methods that remove the entire plant and prevent reproduction are effective but very expensive and can cost hundreds of thousands, if not millions, of dollars to treat just a few acres. Pesticides, on the other hand, are designed to work efficiently and systemically on weeds. They are generally inexpensive and can be applied either as spot treatments on a single weed or sprayed to target the spread of weeds in large areas.

IPMP is reviewed annually to see what new options and techs are available to controls.

VDCI (Vector Disease Control International), the City’s contractor for adult mosquito control, conducts their operations based on specific criteria. ULV adult mosquito control commences within the City when:

• Mosquitos found in traps strategically placed throughout the City reach more than 150 mosquitoes
• AND
• A positive identification of West Nile Virus is found in a mosquito within the three-county area of Weld, Larimer and Boulder Counties.

In general, the City does not eradicate weeds for aesthetic purposes. However, some weeds can be undesirable for human-related activities. For example, uneven surfaces caused by broad-leaf weeds on sports fields can be dangerous to recreationalists and athletes. Weeds that grow stickers or that are poisonous to humans and their pets are also not desirable in City parks. Longmont tries to maintain Neighborhood and Community Parks in conditions that are conducive to sports and general recreational and leisure activities.

The State of Colorado requires the complete eradication of some noxious weeds and the control of many other weeds. Noxious weeds spread fairly quickly and damage valuable habitat or crowd out desired native vegetation. As of March 2017, there are currently 145 weed species included on the Colorado Noxious Weed list, and 25 of those weeds are required to be eradicated upon detection. The City of Longmont also has a weed ordinance that applies to all land within the City limits included land owned by the City.

Weeds are important early succession species that generally pave the way for the establishment of permanent native species after the ground has been disturbed by fire, landslides or other natural disturbances. Unfortunately, with population growth and spreading urbanization, natural ecological processes are interrupted. Vegetated areas in cities like Longmont are generally small in size and fragmented across the urban landscape compared to national forests, state and national parks, preserved grasslands, and other large natural areas. As a result, the natural succession cycle from weed to permanent vegetation is never fully completed in urban areas, and communities must intervene if they hope to establish healthy vegetation. That intervention frequently requires the removal of weeds.

There are no biological control alternatives approved for large-scale adult mosquito control operations at this time.

Pesticides usage in Longmont focus primarily on weed control to preserve natural habitat, ensure compliance with State and local weed ordinances, and to provide quality turf conditions for safe recreational use. They are used infrequently to control some pests such as when pathogens such as West Nile Virus are detected in mosquito populations. Learn more in our Integrated Pest Management Plan.

VDCI uses specialized Ultra-Low Volume (ULV) equipment to control adult mosquitoes. This is conducted with a synthetic pyrethroid treatment, permethrin (commonly found in flea and tick shampoos). Permethrin is a man-made version of a natural insecticide derived from a type of chrysanthemum plant. Permethrin is one of the least-toxic products registered with the U.S. EPA and the State of Colorado for public health mosquito control applications.

The City only sprays for dandelions in shrub beds and athletic turf areas (for player safety). The City’s goal is to never spray grass areas where the public can recreate. Dandelions are not classified as a noxious weed by the Colorado Department of Ag and therefore are not required to be sprayed. The City of Longmont will use other non-chemical methods to limit the amount of dandelions found in grass areas on City property.