Herbicides
Herbicides prevent or eliminate weeds and thus replace or reduce manual and mechanical weeding. Because they reduce the need for cultivation, herbicides can also prevent soil erosion and water loss.
Herbicides can be divided in two categories:
Selective Herbicides:
can be directly applied on specific crops without damaging them.
Non-selective Herbicides (NSH):
eliminate all plants (if absorbed by green tissue). In recent developments, some NSH's can now be used in the same way as Selective Herbicides on crops that are genetically modified in order to make them tolerant to specific herbicides.
Introduction to Selective Herbicides
Weeds are undesirable plants growing within a crop. They compete for resources such as nutrients, water and light. Without weed control, crop yields can be significantly reduced (40-100%) depending on the competitiveness of the crop, composition of the weed flora and level of weed infestation. Weeds can also cause further problems by harboring pests and diseases, interfering with harvest operations, and increasing costs of cleaning and drying the crop produce. For efficient and profitable crop production, appropriate weed management is essential.
Until the mid-19th century, labor-intensive and rather inefficient hand weeding was the only form of control. Later, mechanical measures for weed control were introduced. But only the discovery of selective herbicides in the 20th century eliminated the tedious and demanding task of non-chemical weed control in many countries. These products contributed to substantial increases in yield and consistency of crop production.
Chemical weed management must be achieved without causing damage to the crop. This is referred to as "selective" weed control. Selective herbicides have been derived from a wide range of different chemical classes with varying modes of action. In some cases, "safeners" (eg. cloquintocet) have been developed. These protect a given crop from potential damage caused by a specific herbicide. Selective herbicides have allowed the intensification and spread of key crops such as corn, rice, soybeans and wheat.
Today, selective herbicides are an integral part of modern farming practice globally. They provide a highly efficient, cost-effective, flexible and convenient method of in-crop weed control. Syngenta, the worldwide number one supplier of selective herbicides, offers a portfolio of products that provide solutions for virtually all crops.
Introduction to Non-Selective Herbicides
NSH's are used under different patterns according to the crop:
- In plantation crops (rubber, oil palm, orchards, vines) they are applied on weeds growing between the trees for several purposes: to facilitate passage in tropical crops, to save moisture in vines and orchards, to reduce cultivation or erosion associated with cultivation. Typically these herbicides can be applied without damage to the bark of trees but not to the leaves.
- In annual crops in several modes:
- Preplanting to eliminate weeds prior to planting. The objective is also to reduce cultivation.
- Early post planting prior to crop emergence
- Post planting, interow spraying with spray guards to protect the crops
- Preharvest to desiccate weeds and crops
- Post harvest to reduce perennial weeds.
NSH's mostly belong to two groups according to their properties:
- Contact herbicides (and or desiccants) only affect the area sprayed, they are usually fast acting and rainfast. They work well on annual species and are adapted to quickly remove the vegetation prior to planting especially in tropical environment. Roots remain intact thus allowing good erosion prevention. Gramoxone is a good example of this class.
- Systemic herbicides: the product moves within the plant from the point of contact, typically towards the growing points that will be destroyed. They are well adapted to controlling perennial species that have strong root systems. They usually require time to penetrate and migrate within the plant and tend to be slow acting. Touchdown is a good example of such products.
Complete brand list selective herbicides
| Product Main Brands | Main Countries of Use | Description |
|---|---|---|
| ACHIEVE® / GRASP® | USA, Canada | A post-emergence product for excellent control of wild oats, rye grass and other annual grass weeds with selectivity in both barley and wheat. |
| APIRO® | S.Korea | A herbicide for consistent control of annual grasses in paddy rice, with the flexibility to apply from pre-emergence up to the 3-leaf stage. |
| AXIAL™ | USA, Canada, Germany, UK | A post-emergence tailor-made solution that offers control of an extended spectrum of grass weeds in wheat and barley and is based on the innovative chemistry of pinoxaden - the latest herbicide active ingredient developed by Syngenta. |
| BANVEL® | France, Argentina, Russia, Hungary, Spain | A well-established product for perennial broad-leaf weed control, primarily in corn and cereals, and also turf, pasture and non-crop land. |
| BEACON® | USA | A highly selective herbicide to control key annual broad-leaf weeds and perennial grasses in corn and grass seed production. |
| BICEP II MAGNUM® / PRIMEXTRA® GOLD |
USA, Brazil, Australia, Hungary, Spain | BICEP II MAGNUM is a strong, longer lasting corn herbicide for season-long, broad-spectrum weed control, and unequalled crop safety. |
| BOXER® | Denmark, Germany, Netherlands | A pre-emergence or early post-emergence herbicide for the control of grass and broad-leaved weeds in winter cereals and potatoes. |
| CALLISTO® | USA, France, Germany, Italy, Spain, Belgium | A unique corn herbicide developed from nature providing unprecedented broad-leaf weed control, with the flexibility to be apply at any time and excellent environmental, crop and human safety. |
| CAMIX™ | USA | CAMIX is a unique broad spectrum, broadleaf and grassweed corn herbicide, for use pre-emergence to early post-emergence, which provides: - Flexibility of use without restrictions - Unmatched safety to crop and land - Control of all herbicide resistant weeds |
| COLZOR TRIO® | France, Poland | A broad-spectrum, pre-emergence herbicide specifically designed for oilseed rape. |
| DUAL® GOLD® / DUAL II MAGNUM® |
USA, Canada, Brazil, Argentina, China, Russia, Ukraine, France, Italy | A new highly active, reduced rate product providing season long grass control in corn and soybean. |
| ENVOKE™ | Brazil, Argentina, Australia, USA | A unique new tool for herbicide programs in cotton, offering a high degree of strength, flexibility and choice to the grower. |
| FLEX® | Brazil, Mexico, Argentina, France | A highly selective product for the control of broad-leaved weeds in soybeans, dry beans and peas. |
| FUSILADE® / FUSION® | USA, Brazil, Mexico, France, Germany, Greece, Italy, Spain | With registrations in more than 60 crops and sales in over 50 countries, FUSILADE® is the leading post-emergence graminicide for broad-leaf crops worldwide. |
| GESAGARD® | Brazil, Mexico, Australia, Bulgaria, Greece | For use in cotton, sunflowers and vegetable crops, GESAGARD® provides effective control both pre- and post-emergence of a wide range of annual broad-leaf and grass weeds. |
| GESAPAX® | Mexico, Colombia, Cuba, Australia, S.Africa, Thailand | With flexibility for pre- or post-emergence applications and good residual activity, GESAPAX® is ideally suited for use in sugarcane, bananas and pineapples. |
| GESAPRIM® / AATREX® | USA, Canada, Mexico, Venezuela, Argentina, Australia, Thailand, Japan, S.Africa | With excellent selectivity in corn and sugarcane, GESAPRIM®/AATREX® offers reliable control of annual grass and broad-leaf weeds, and is a perfect partner for mixing with grass weed products. It can also be used in sorghum crops. |
| KRISMAT™ | Brazil, Colombia | A new broad-spectrum, post-emergence herbicide setting a new standard for weed control in sugarcane. |
| LENTAGRAN® | Germany, UK, Czech Republic | A highly selective herbicide to control annual broad-leaf weeds, including triazine and sulfonylurea resistant weeds, in corn, sweet corn and some vegetable crops. |
| LOGRAN® / AMBER® | Australia, USA, Russia, Spain, Italy | With excellent selectivity in all cereal crops, this product delivers season-long control of broadleaf and grass weeds, both pre- and post-emergence. |
| LUMAX™ | USA | A breakthrough, one-pass solution for corn, which offers new standards of crop safety and meets the challenge of season-long control of broadleaf weeds and grasses. |
| MILAGRO® | Poland, Czech Republic, Belarus, Greece, Netherlands | MILAGRO offers reliable control of annual and perennial grasses in corn. With excellent translocation properties, it is a perfect partner for post-emergence herbicides for broad-leaf weed control. |
| NORTHSTAR® | USA | A twin-action corn herbicide for consistent control of a broad range of grass and broadleaf weeds in corn. |
| ORDRAM® | USA, China, Turkey, Italy | ORDRAM® offers growers full flexibility to control grasses, in particular Echinochloa species, in rice. It can be applied pre-planting, pre-emergence or post-emergence. |
| PEAK® | USA, Argentina, Canada, S.Africa | A post-emergence herbicide with residual activity for the control of a broad spectrum of annual broadleaf weeds in corn, sorghum and cereals. |
| RIFIT® | India, Bangladesh, S.Korea, Japan | A pre- and early post-emergence herbicide that offers effective control of annual grasses, some sedges and broadleaf weeds in transplanted and dry-sown flooded rice. |
| SETOFF® | Italy, Spain | SETOFF® offers post-emergence control of most annual and perennial broadleaved weeds and sedges in transplanted and direct-seeded rice grown under tropical or temperate climatic conditions. |
| SUPREND™ | USA | SUPREND™ has been specifically designed for cotton. It combines superior crop safety with broad-spectrum weed control, including the difficult-to-control cotton weeds. The ready-mix formulation of SUPREND gives cotton growers greater convenience and ease of use. |
| TOPIK® / DISCOVER® / HORIZON® | USA, Canada, Mexico, Argentina, Chile, Australia, India, Iran, Spain, Italy , UK, Germany | A post-emergence grass herbicide with excellent selectivity on all varieties of wheat, rye and triticale, and to some minor extend in rice. |
Complete brand list non-selective herbicides
| Product Main Brands | Main Countries of Use | Description |
|---|---|---|
| GRAMOXONE® | USA, China, Mexico, Thailand, Malaysia, Japan | GRAMOXONE is a unique, fast acting, non-selective, contact herbicide with many varied uses in the control and management of weeds in a wide variety of crops. |
| TOUCHDOWN® | USA, Brazil, Canada, Spain, Japan | Through the integration of unique IQ technology, new TOUCHDOWN is the most innovative solution available today for controlling broad leaf weeds and grasses. |
| REGLONE® | USA, Canada, Brazil, France, Germany | REGLONE is the leading market desiccant. REGLONE works as a fast acting contact herbicide, and is simply the most effective and versatile chemical desiccant available. Used throughout the world, and for over 40 years, REGLONE has a proven track record of successful use and plays a vital role in the management of successful harvests, contributing both to optimum yields and crop quality. |
