CHEMICAL CONTROL OF WEEDS
Chemicals are cheap, long lasting, and the ground is not disturbed. Mixes are useful. They will be unnecessary if the preventative and cultural measures are employed well and frequently. The best situation in which to use them is in preparing or clearing new ground or in inaccessible places and hard landscapes. Many of these items are only available to professionals as of recent new laws (1999). Chemical type & usage information correct as of 1997. |
3.0 Chemical | |
3.1 Foliage Acting |
Chemicals acting on the plant, enter through the leaves. |
3.1.1 Translocated |
All types: Growing weeds: Inactive to soil. Moves from the leaves to the roots, destroying all. Used in vigorous growth. |
3.1.1a Glyphosate |
Inactive to soil. Do not use on lawns or beds. Kills all main weeds. |
3.1.1b Amitrole |
Control for cracks, crevices and paving. |
3.1.2 Contact |
Annuals : In-between shrubs: Growing weeds. Kills by direct contact, best for annuals. |
3.1.2a Paraquat/diquat |
Good for annuals. Also checks perennials. Any time, best in spring to kill overwintering annuals. Avoid all shrubs and green growth. |
3.1.2b Dichlorophen |
Algal growth, moss.liverwort on stone |
3.2 Soil Acting |
All Weed Seeds: Bare ground: In-between shrubs. Long lasting, residual. Applied to soil, and absorbed by roots of growing weeds, and then move to leafy growth. Best for emerging seedlings. |
3.2.1 Propachlor | Good for annuals in borders and veg plots. Few weeks only |
3.2.2 Simazine | High rates kill all weeds for 12 months. Low Rates: controls germinating seeds in shrub beds for 7 months. Use limited to Feb/March to moist free soils. May be damaging to shrubs. |
3.2.3 Ammonium sulphamate | Controls many herbaceous plants, tree stumps, 12 week residual. |
3.2.4 Dichlobenil |
Applied around bushes and shrubs that are two years old to suppress perennials and annuals and germinating seeds. Acts for several months. Best in March or April when soil is moist. May damage some trees. |
3.3 Selective |
These kill broad leafed dicots, and leave narrow leafed monocots alone, or visa versa. Best used in lawns. |
3.3.1 Alloxydium-sodium |
kills perennial grasses. |
3.3.2 Mecoprop/ |
kills most broadleafs in a lawn. |
3.3.3 Dichlorophen |
Kills moss. |
3.3.4 MCPA |
In lawns for those resistant to the above |
Weedkiller Use: Precautions
Precautions Before Using A Weedkiller.
Make sure you have purchased the correct chemical
Code Of Practice For Herbicide Usage
Only use approved herbicides Protection Of Public
Follow precautions as detailed in label.
Protection Of Farm Animals Wildlife
Protect animals and wildlife from sprayed areas until diluted
Protection Of Crops and Shrubs
Avoid spraying directly onto above |
Information Collated by James M. Burton as part of H.N.D. Course at Pencoed Agricultural College.
Chemical Information Correct as of 06:06:97. Always read and follow the instruction when using herbicides.