Weed management can be frustrating to many farmers as some weeds are tough to control.
Unlike cultivated crops that require a lot of nurturing to survive, weeds are fast-growing and need little nutrients to dominate the field.
If care is not taking, weeds can drastically reduce the income of the farmer by rendering the planted crop unproductive.
As a farmer, you have to be familiar with how to handle these unwanted guests using the chemical control method.
What are Herbicide?
Herbicides are chemicals that are toxic to the plants and are capable of utterly destroying them or slowing down their growth.
You have to consider many factors such as the type of cultivated crop, the species of the common weeds, the age of the weed amongst other several factors before you can determine which type of herbicides to use.
Here are the lists of the types of the eight popular herbicides that you have to know to be successful as a farmer, lawn owner or horticulturist.
1. Pre-emergent Herbicide
These are herbicides that are used as a preventive measure against weeds rather than control.
Pre-emergency herbicides are targeted at preventing the germination of the seeds of these weeds, and as such, you have to consider the timing of application.
The best time to apply pre-emergence herbicide is when after planting your seed but before they germinate.
As in weeds, pre-emergence herbicide will attack the crops so you must be careful to avoid application when your planted seeds have begun to sprout.
Pre-emergent herbicide usually has a long-term effect on weed control since they act on the seeds of weeds.
2. Post-emergent Herbicide
Application of post-emergent herbicides means that you are focused on destroying the vegetative parts of the weeds and not necessarily their seeds.
Post-emergent herbicide will kill the leaves of the weeds without causing any harm to the seeds that are still in the soil.
A commonly used example of post-emergent herbicide is Round-Up.
3. Contact Herbicide
Just like the name implies, contact herbicides means that the chemical works by getting in touch with the leaves of the weeds that you want to destroy.
To get a better result when applying contact herbicide, you must ensure that the herbicide wholly covers the weeds to be controlled.
Contact herbicides are fast in their mode of action, within 24 hours, you will notice the burns on the weeds.
The only downside to contact herbicide is that it doesn’t give a lasting effect and neither does it affect the root of weeds.
Contact herbicides are usually cost-effective and readily available in the market.
A popular example of contact herbicide is paraquat
4. Systemic Herbicide
Otherwise called translocated herbicide, systemic herbicide act on the tissues (xylem and phloem) of weeds through the transport mechanism within the plants.
During photosynthesis, water and nutrients are translocated to the phloem tissue for absorption, as such, the harmful chemicals are transported along which gradually affect the weeds system until they eventually dry off.
Systemic herbicide is more effective as it destroyed both the shoot and the root of weeds using the vascular system of the plant.
Their only drawback is that they can take up to two weeks before you can observe the effects on weeds.
Glyphosate is an excellent example of systemic herbicide.
5. Non-selective Herbicide
Also known as knockdown, this type of herbicide kills all kinds of plants.
It cannot distinguish between weeds and crops.
Thus, you should only apply non-selective herbicide before plant your crop.
However, some species of weed may offer resistance.
When this occurs, you should try a second application or change the brand of the herbicide you used
If you want to enjoy the effects of non-selective herbicide to the maximum, you should try to apply it 3-4 days before planting.
Non-selective herbicide can either be contact or systemic.
6. Selective Herbicide
Preferences or selection are shown in selective herbicides.
For instance, if you plant rice a selective herbicide for rice will kill the weed in the categories of broad leaves, sedges, and thistle but may not affect any weeds that belong to the grass family.
However, there are selective herbicides that will spare the crop only and kill other forms of weeds whether grasses or broadleaves.
Selective herbicides can also be contact or systemic.
7. Residual Herbicide
With the increasing resistance shown by weed, residual herbicide can bring about long time effectiveness especially when they possess many modes of action.
If you want to experience a severe delay in the growth of weeds, you should consider going for residual herbicides.
Some pre-emergent herbicides fit into the category of residual herbicides.
You should mainly use residual herbicides if you notice that some species of weeds are showing resistance to the use of herbicide.
8. Drench Herbicide
If you are thinking of eliminating nay growth of weed for a long time, you should consider using a drench herbicide.
Drench herbicides are mostly applied directly to the soil with or without the plants. They have the most extended duration for effectiveness, and if rightly applied, you will see that no weeds will germinate for a long time.
However, as this can affect the growth of the plant too, it is not suitable for use when you intend to cultivate crop in such area of application.
Irrespective of the type of herbicides you are using, the first thing to do before you can apply any herbicide is to check the label for the direction of use.
A lot of people are guilty of assuming that they know it all, and occasionally they make a costly mistake that can jeopardize the health of their cultivated crop.
Also, all ways check for the expiry date before you make a purchase.
An expired herbicide may not be effective or can work abnormally when applied.
The best temperature to apply is at 25ºC.
If above that, it may speed up the rate of herbicide activity but could cause harms to plants especially when you are using a selective herbicide.
Herbicides are useful in weed management, and knowing the various types that exist will help in your decision making.