Herbicides are a type of chemical that can be used to kill plants. They can be used on crops, lawns, and gardens. Herbicides work by either preventing the plant from forming essential proteins or by disrupting the way those proteins are put together. Some herbicides are also used as defoliants, which means they will cause leaves to fall off trees before they can produce seeds. Some common examples of herbicides include Glyphosate, Atrazine, and 2,4-D.
Herbicides come in many different forms, including solid pellets and liquids. Some herbicides must be ingested by the plant to be effective, while others can be absorbed through the leaves or roots. Some will kill only broadleaf weeds, while others will kill both grasses and broadleaf weeds. Most herbicides work by disrupting photosynthesis in the leaves or roots of a plant (or both).
Herbicides are chemicals used to kill weeds (unwanted plants) that tend to compete with the grown crops. Herbicides can be selective or non-selective. Each of these groups can be sub-divided into three namely;
These are weed killers which by their chemical composition are capable of acting bio-chemically on either broad-leaved weeds or grasses. They are used predominately in monocropping situations. However, when these herbicides are used in high concentrations, they tend to have phytotoxic effects on cultivated crops. Selective herbicides that kill grasses only are Alachlor, Pendimethalin, etc. also those that kill broad leaves weeds only are Atrazine, Imasaquine, etc.
A selective pre-emergent herbicide kills weeds as they germinate from their seeds, but leaves an established lawn safe to continue thriving. Broad-leaf weeds are easily controlled with a selective post-emergent herbicide as they are much more biologically diverse from your grass lawn. They are targeted at killing broadleafs while leaving grass plants to thrive.
How Selective Herbicides Work
Selective herbicides are designed to work in a particular way: they target specific plants while allowing other plants to grow. They work by targeting specific metabolic processes that plants rely on to survive. Not all plants have the same metabolic processes, so by using a selective herbicide that is safe for your plants or lawn, you can target and eliminate specific weeds without risking your lawn.
Selective herbicides work by interfering with the plant’s ability to absorb nutrients, damaging the plant’s roots and leaves. This makes it harder for the plant to grow and compete with other plants around it.
Selective herbicides work by inhibiting a plant hormone called auxin. This hormone causes cells to grow and divide, which produces new plant growth. Inhibiting auxin allows selective herbicides to kill the targeted plant while leaving nearby plants unaffected.
Some selective herbicides are applied only when the soil is moist (such as post-emergent grass control), while others are applied when the soil dries out (such as pre-emergent weed control).
In addition to nonselective herbicides, there are also selective herbicides that target certain plant parts or stages of growth. These can be used alone or in combination with nonselective herbicides to create an effective weed management system that works well on a variety of crops.
For example, Tenacity Herbicide is a herbicide that controls broadleaf weeds, white clover, plantain, capeweed, cat’s ear, and creeping oxalis. It is also suitable for use on zoysia grass, kikuyu grass, couch grass, and buffalo grass.
Examples of selective commercial herbicides are:
#1. AXIAL 045EC: this is the first of a family of tailor-made cereal grass weed solutions to be introduced to growers globally. It has been developed for worldwide use in both wheat and barley and offers unrivaled crop tolerance. It is highly compatible with many broadleaf herbicides.
#2. Turflon Ester Ultra: This is a post-emergent herbicide that works best on broadleaf weeds and vines such as kudzu and ivy.
#3. Battleship III Herbicide: This is a selective post-emergent herbicide that contains Triclopyr, Fluroxypyr, and MCPA and contains no 2,4-D for cool & warm-season grasses.
#4. DUAL GOLD 960EC: is another pre-emergence herbicide that can be used to control annual grass weeds and some annual broad-leaved weeds in pulses, maize, and Sugarcane. It exhibits excellent selectivity with superior safety on a wide range of crops.
#5. T-Zone SE: This selective herbicide contains several active ingredients; this makes it cover a wide spectrum of tough weeds. The Triclopyr component kills ground ivy, wild violet oxalis, and wild blackberry. The Sulfentrazone chemical is responsible for the rapid weed elimination of species like spurge, white clover, and dandelions. The 2,4-D present targets the growth regulator of plants causing curling and twisting of the weeds, which leads to the death of the plant. Dicamba, the fourth component, is responsible for inhibiting the growth of tough weeds as it reaches the leaves and roots.
#6. FUSILADE FORTE 150EC: is a superior post-emergence grass weed herbicide that is used in fruits and vegetables. Fusilade Forte is applied when weeds are between the 2- 8 leaf stage. Fusilade Forte kills all germinated Grass weeds and is able to select a wide variety of vegetables and fruits. It gives all-season grass weed control eliminating the need for manual weeding.
#7. LUMAX 537.5SE: is a herbicide for pre and post-emergence control of grasses and broad-leaf weeds in maize and sugarcane. It can be applied as pre or post-emergence of both the weed and the crop.
#8. TRAXOS 045EC: This is another effective post-emergence herbicide for the control of annual grasses in wheat. It is safe for the crops and environment due to the Safener.
#9. Tenacity Herbicide: This is an effective systemic selective pre and post-emergent herbicide that controls broadleaf weeds and grasses in cool & warm-season turf.
#10. SedgeHammer Herbicide: This is another selective post-emergent herbicide for the control of nutsedge and other weeds in turf-grass and landscaped areas.
Other active ingredients are:
- Basamaize for maize.
- Ronster for rice.
- Galex for cowpea, soyabeans, groundnut.
- Bagram for rice and maize.
- Cotoran for cassava.
- Primextra for maize, cassava and yam.
- Diuron for yam and cassava.
Non-selective herbicides are a class of herbicides that can be used in many different situations. They are most often used to control weeds in lawns, gardens, and other outdoor areas. These herbicides don’t discriminate between plants and other organisms, so they can kill both plants and weeds. Non-selective herbicides are also known as broadleaf weed killers.
These are otherwise known as total weed killers. They are used for weed control in any weed combination in the field, they will kill any kind of vegetation. An example is Glyphosate (Round-up).
Types of Non-Selective Herbicides
There are four main types of non-selective herbicides: Glyphosate (Roundup), 2,4-D, dicamba, and triclopyr. The first three are typically applied as liquid formulations while triclopyr is usually applied as a granular formulation. Each type has its own advantages and disadvantages depending on the situation you’re facing with your lawn or garden.
#1. Glyphosate: a broad spectrum, systemic herbicide that controls annual and perennial weeds, grasses, brush, and woody brush. Glyphosate can be used on both cropland and non-cropland sites. It is sold under the trade names Roundup, Rodeo, and others.
#2. 2,4-D (or dicamba): a selective plant killer that has been used for decades as a broadleaf weed control agent. It works by inhibiting the production of an enzyme called acetolactate synthase which is essential for photosynthesis. It can be applied to a wide range of crops including soybeans, corn, cereals, and cotton. 2,4-D can also be used in hay fields as long as it is applied before flowering begins in order to prevent seed formation.
Difference Between Selective And Non-selective Herbicides
Selective herbicides are designed to kill only certain types of plants. For example, if you wanted to kill all the weeds in your lawn but not your grass, a selective herbicide would be the solution. Non-selective herbicides are designed to kill all plants and weeds.
Non-selective herbicides are often more effective on broadleaf weeds than on grasses because broadleaf weeds have more complex root structures that make it harder for them to absorb the chemicals.
Classification Of Herbicides By Mode Of Action
According to their mode of action, herbicides can be classified as:
- Residual herbicides
- Systemic Herbicides
Herbicides are chemicals that kill weeds by contact, which means the herbicide moves into and affects only the part of the plant that it comes into contact with. Herbicides were the first type of chemical used to control weeds, and they still have a significant advantage over other types of herbicides when used correctly. They usually control small weeds with good coverage; however, some can also kill large Malva, Purslane, and some other difficult-to-kill weeds. These types of herbicides kill any vegetation or weeds immediately after application. They stop all biological activities.
Examples of contact herbicides are diclofop, dinoseb, diquat, and paraquat. Certain contact herbicides, like diquat and paraquat, are deactivated by soil particles. They must be mixed with clear water and applied directly to the vegetation.
Systemic herbicides are slow-to-action types whose effects are not noticed until a few days or weeks after application. They can be translocated to other parts of the plant. Their effect is a thorough but gradual killing of the most stubborn and perennial weeds. They have the ability to move around the transportation and translocation systems to achieve a total kill.
They alter the normal biological function of the plant by interfering with certain biochemical reactions. Thus, when applied to foliage or soil, they enter the plant and translocate to their site of action. Examples of translocated herbicides are atrazine, glyphosate 2,4-dichloro phenoxy acetic acid (2,4-D), and simazine. Systemic herbicides, like contact herbicides, also have diverse modes of action at the molecular level.
These are soil-acting weed killers whose effects on weed control are primarily as photosynthetic inhibitors. They can have both pre and post-emergence activity; they are applied to the soil after cultivation and effectively control germinating weed seeds. Examples are simazine, Diuron, etc.
Classification Of Herbicides Based On Time Of Usage
PRE-PLANTING HERBICIDES: This can be a foliar; selective or non-selective herbicide, applied before the crop is planted. Examples are Glyphosate , Paraquat.
PRE-EMERGENCE HERBICIDES: These are applied in the soil before the emergence of weeds, immediately after cultivation e.g Galex + Metolachar used for cowpea, Cotoran used for cassava, etc. You can buy any of these Pre-Emergence Herbicides For Weeds Control
POSTEMERGENCE HERBICIDES: These are applied after the emergence of weeds and can have both contact and systemic actions, but are usually selective so as not to have a phytotoxicity effect on the cultivated crops. Examples are Laddox in maize, Paraquat, Propanil, and Glyphosate.
How To Apply Herbicides
There are several Herbicide application methods. Herbicides are a lot like fertilizer. They’re meant to encourage plant growth, and they can help you get the most out of your yard.
The first step in applying herbicides is to identify the type of herbicide that you’re using. This is important because different herbicides work best on different types of weeds.
There are two main types of herbicides: systemic and non-systemic. Systemic herbicides work by entering through the leaves and penetrating deep into the plant’s vascular system. Non-systemic herbicides are absorbed through the leaves and affect only the top few inches of a plant’s growth.
Systemic herbicides are applied directly to plants with a sprinkler, sprayer, or backpack sprayer. They’ll need to be mixed with an appropriate amount of water before they can be applied to the ground or plant stems (which will need to be cut). To use these products, simply follow instructions on how much product you should use per area (usually about 10-20 gallons per acre).
Non-systemic herbicides can also be used for weed control but are typically applied as dry granules or pellets that are mixed into soils at a rate of 1 pound per 1000 square feet (about 1/2 lb/yd2). These products will need to be watered before they’re applied.
#1. Apply herbicides with a spreader sticker: This is the most common method of application, and it involves placing a sticker on the surface you’re treating, then spraying herbicide into the hole in the sticker. You can also use this method to apply mists to plants.
#2. Use a backpack sprayer: This is a sprayer that’s mounted on a stand so that you can spray herbicides at any angle or distance from your body while they’re still contained within the backpack. It’s usually more expensive than other types of sprayers, but it’s convenient if you want to apply relatively large quantities of herbicide without having to use lots of different nozzles and accessories (which could be difficult when using conventional sprayers).
#3. Use an air foamer: These are often used by professional gardeners who want to treat large areas with herbicides without having to move around too much, they’re often mounted on wheels or rails so that they can move around easily while spraying herbicides onto plants in different directions.
Herbicides are chemicals that can be used to kill unwanted plants and weeds. They’re effective because they can kill plants that are growing in areas where they’re not wanted, such as lawns and gardens. There are several different types of herbicides and they work in different ways.