Organic Control of Perennial Weeds with Vinegar and Biologicals

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2011: $20,790.00
Projected End Date: 12/31/2012
Region: Western
State: Montana
Principal Investigator:
Jess Alger
Organic control of Perennial Weeds

Annual Reports


  • Agronomic: grass (misc. perennial), hay
  • Vegetables: lentils, peas (culinary)
  • Additional Plants: native plants
  • Animals: bovine


  • Animal Production: grazing management, pasture renovation, preventive practices, range improvement, feed/forage
  • Crop Production: cover crops, fallow, application rate management
  • Education and Training: demonstration, extension, farmer to farmer, networking, on-farm/ranch research
  • Farm Business Management: whole farm planning
  • Pest Management: biological control, botanical pesticides, chemical control, field monitoring/scouting, weed ecology
  • Production Systems: organic agriculture, transitioning to organic
  • Soil Management: green manures
  • Sustainable Communities: sustainability measures

    Proposal summary:

    Dealing with weeds is very costly and time consuming. Weed management often does not get the high priority it should have because of lack of manpower to handle all of the other duties and responsibilities on an operation.

    It is our goal to look for a combined solution to control the non-native weeds with the least impact to the ecosystem.

    The producers involved are located in Central Montana, and all are certified organic. Jan & Rich Boyle raise irrigated hay and garden produce. Water-borne knapweed on irrigation banks are a special problem they will work on. Bob Herdegen is a dry land producer of hay, grain and beef cattle with knapweed and Canada Thistle and Leafy Spurge. Casey Bailey is a dry land grain and alfalfa producer with lots of coulees where he will be reducing weed populations of Canada Thistle. Jess Alger is a dry land producer of grain, hay and beef cattle whose worst problem is White Top in both crop and pasture.

    We will investigate organic methods of controlling perennial range and cropland weeds using spray applications of vinegar and by releasing beneficial biological organisms(weevils, mites and beetles).

    White Top is a common weed for which there is no biological control yet available. We will look at controlling it with vinegar applications. We will attempt to find the most appropriate equipment to use and the best times to apply spray (emergence, bloom or late-season cleanup?). White Top is spreading in Central Montana. Eradication is not possible but killing large areas would sure make people smile. In hay fields, the White Top sets seed about the time the hay is cut. Then in the winter where the hay is fed, the White Top seeds are tromped into the ground, and ranchers have more patches of White Top growing on their place.

    Field bindweed is notoriously difficult to eradicate. We will spray our patches with vinegar and/or obtain, release and manage bindweed mites. Dr. Jeffrey Littlefield of Montana State University says he will collect Field Bindweed mites to put on our patches. They seem to work best in dry land environments. He said they help but will not eradicate the plant completely. Field Bindweed can take over a whole field if you let it. It is spread by deer and antelope and dragging from field to field on plows.

    We will investigate methods of controlling Canada Thistle. There are at least two different biologicals available for Canada Thistle, stem gall wasps and stem weevils. The stem weevils seem like they would work best for us, and they seem to kill the plant. The stem gall wasp reduces seed production, which seems not enough control for us. We will spray some patches with vinegar. We will swath some patches. We will plant alfalfa in the fields that are badly infested with Canada Thistle.

    Knapweed is another weed we will try vinegar and beneficial biologicals on. There are probably more acres of Knapweed in Montana than any other weed.

    We will use Weed Guard mesh on some patches of weeds; it is supposed to let the moisture in to sprout the seeds of the weed you are going after. Then when the suns comes out, it bakes the plants that are sprouted under the black plastic mesh.

    We will document all of the patches and results of our efforts on all four operations. We will use cameras and GPS systems to find again the patches that we have sprayed or released beneficial biological organisms in. We will use step in electric fence posts to mark some of the spots of weeds; on a flat field this may help some.

    Project objectives from proposal:

    This grant will enable us to:

    1) Reduce the spreading of weeds on our properties, thus making our land more productive,

    2) Monitor for noxious weeds,

    3) We will be better neighbors by not spreading weed seeds to neighboring property, and the beneficial biological populations we will establish will spread to our neighbors' weeds,

    4) Be better stewards of the land by reducing weed populations via nontoxic and organically approved means, keeping our soils healthy, and surface and ground water uncontaminated,

    5) Find and disseminate information about controlling weeds in an organic system in cost- and time-effective ways.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.