Herbicide Alternatives Research - Executive Office of Transportation

locations can be more expensive than mowing with machinery and can put the operator in a
hazardous situation.
Cultural control involves practices that promote the growth of desirable plants that, once
established, can successfully compete against weeds and will provide a relatively lowmaintenance,
as well as aesthetically pleasing, vegetation. Emphasis is typically on restoring
native species or providing high visual interest, such as with wildflower plantings (Henderson,
2000). Other means of vegetative control are typically required to get these plants established,
and once established, plantings such as grasslands or wildflowers will require routine mowing or
burning to keep woody species from establishing and dominating the area over time.
Biological control involves the use of mammals, insects, bacteria, fungi, or viruses to manage
plant growth. Few instances of biological control appear to be in practice by state departments of
transportation. In general, managers require more research to be performed on biological control
before recommending its use along roadsides.
Reviews of published or accessible literature and of practices used by state departments of
transportation were conducted to determine and to evaluate alternative methods to the use of
conventional chemical herbicides in management of vegetation. Alternative methods were
considered to be those that involved mechanical, cultural, or biological control and certain
chemical control methods that utilize herbicides developed from natural products.
2.1.1 Need for Research
Currently, the use of synthetic chemical herbicides is one of the most important approaches to
controlling weeds along highways. However, the use of these chemicals has drawn the attention
of the general public, political decision-makers, and environmental groups who have called for
restrictions on herbicide use (Owens, 1999; Clary, 1999) and the adoption of alternatives to
herbicides use for weed control along roads (Young, 2002). Many states, including
Massachusetts, have adopted practices of right-to-know; public notification and comment
policies; and restrictions on herbicide handling. Additionally, many states have adopted plans of
integrated-pest-management (IPM)-based programs for vegetation management with the goals of
reducing use of chemical herbicide and studying of appropriate alternatives to herbicides.
Owens (1999) has reviewed the roadside rights-of-way weed management policies and program
for many states.
This review covers a number of weed control methods that are alternatives to use of conventional
herbicides. Generally, the literature on these methods comes from research in production
agriculture, extensive reviews can be found on this subject (Parish, 1990; Bond and Grundy,
2001; Bond et al., 2003). However, the roadside applications of most alternatives have received
little or no extensive or systematic testing.
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