Roadsides and Non-crop Areas: Perennial Weed Control (Non-crop Land)

Excerpt from 2008 Chapter 18, Publication 75, Guide to Weed Control, Order this publication

Introduction

• CAUTION: Unless otherwise recommended, do not use these treatments in crop situations. Avoid using if the chemical is likely to wash or leach into areas occupied by the roots of desirable trees or other plants. Follow all precautions to avoid spray drift onto non target vegetation.
• The use of atrazine, simazine, bromacil, or diuron non-selectively, as described, is generally limited by cost to the handling of small patches of perennial weeds. The chemical either leaches down to the weed root system or makes the surface soil toxic for a period of time varying from a few months to several years, depending on the chemical, rate of application and soil type. Generally, crops cannot be grown successfully until the effect of the chemical has disappeared. Corn, however, can be grown safely when high rates of simazine and atrazine are applied.
• Some perennial weeds, such as field bindweed, horsetail, goldenrod, milkweed and bracken fern, are difficult to eradicate at the lower rates of diuron, simazine, atrazine and bromacil. Follow the manufacturer's directions carefully if the area is to be re-seeded. The amitrole treatment is of value in spot treating patches of quackgrass in a field that is not entirely infested.
• While the tops of many perennial weeds may be controlled by doses of 2,4-D that may be selectively used in resistant crops, heavier doses, as described, must be used if eradication is to be attempted. Several applications upon successive stages of regrowth will probably be necessary. Generally, treatments with 2,4-D during rapid development of the weed at about the early bud to flowering stages of growth are most effective. Apply spray to thoroughly wet all foliage.
• Heavier doses of 2,4-D on patches of weeds may be applied during normal selective spraying operations merely by slowing down the sprayer speed in the infested areas. Expect local crop damage where this is done.
• Perennial weeds are more difficult to control than annual weeds because regrowth occurs rapidly from underground parts after the top growth is removed by chemical or mechanical means. In non-crop land they pose a special problem because cultivation cannot be used for their control. Chemicals must kill the root system as well as the above ground parts to give effective perennial weed control.

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Related Links

• Weeds in Ontario
• Problem Weed Control in Field Crops
• Integrated Pest Management (IPM)
• Pesticide Application and Safety
• Pesticide Companies and Agents
• OMAFRA Sprayer Calibration Calculator
• Search the PMRA website
• OMAFRA Publication 505: Ontario Weeds
• OMAFRA Publication 75: Guide To Weed Control

   

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