✅Definitions, Product uses, Generalised mode of action.

Agricura PVT Limited presents:
Acknowledgements: CropLife Zimbabwe


✅These are compounds used to control weeds, which are normally defined as plants growing out of place. Herbicides can be divided into different categories according to their selectivity and timing of application.

Non-selective or selective herbicides
A non selective herbicide will influence any plant with which it comes into contact, while a selective herbicide will control certain weeds without harming the crop.

Pre-emergent herbicides

These are applied at planting on or in the soil before the germination of weed seeds takes place, controlling the weed during seed germination or just before or immediately after emergence of the seedling from the soil.

Post-emergent herbicides

These are applied on growing weeds after they have emerged from the soil. Post emergence herbicides may be:

Contact compounds i.e controlling only the foliage exposed to the herbicide.

Systemic compounds which are those taken up by the foliage or other parts of the plant, translocated by the water conducting tissues, and then controlling the weed by interference with its normal physiological functions. These compounds may also be taken up by the roots and then translocated to the leaves.


These are compounds specifically developed to control nematodes. Amongst this group we find compounds with the following modes of action:

Contact nematicide is referred to when nematodes are controlled when they come into contact with the compound.

Systemic nematicide is absorbed by the plant and nematodes are controlled inside the infested tissue or when feeding on the plant tissue.

Soil fumigant is spread through the soil in the gaseous phase controlling the nematodes on contact. Nematicide may have a combination of the above mentioned properties.


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