Continuous herbicides, or, as they are also called, non-selective, have an effect on all the vegetation that is on the field. Such herbicides penetrate the plant through the leafy green surface. These substances are used if there are no cultivated plants on the field, that is, either in pairs, or before sowing, or after harvesting. However, the latest developments have allowed the use of a continuous herbicide in the same way as selective herbicides. This became possible due to the cultivation of genetically modified crops, such as sugar beets, potatoes, and soy. These cultures have a special gene for resistance to certain herbicides that do not adversely affect plants.
There are several ways to use these substances that are directly dependent on the culture. On annual crops, one can pre - sow field cultivation. This is done in order to prevent the appearance of weeds and reduce the number of mechanical treatments. You can also carry out early treatment after sowing before the plant has sprouted. For desiccation of weeds and crops, pre-harvest treatment is carried out. To suppress perennial weeds, post-harvest treatment is needed.
On perennial crops, that is, in orchards, vineyards, the processing is carried out between the trees so that continuous herbicides do not fall on the cultivated plants. This is done to prevent weeds, retain moisture and reduce the number of cultivations. Thanks to this treatment, soil erosion, which is caused by frequent cultivation , is prevented.
Continuous herbicides are divided according to the methods of application and signs of action on plants into 3 groups: contact exposure, systemic action and which affect the root system and germinating seeds.
Contact herbicides include drugs that affect stems and leaves of weeds in direct contact with the drug. Such herbicides are characterized in that they quickly act on weeds and are resistant to rain. Upon contact with the substance, the normal life processes of the weed are disturbed, and it dies. However, there is a drawback - quite often there may be an increase in new shoots.
Systemic herbicides against weeds act a little differently . The active substance gradually moves from the place of contact with the surface of the weed to the place of growth of the plant, causing rapid death. Such substances perfectly fight perennial weeds that have a strong root system, but they absorb much more slowly and move through the plant.
The third group includes continuous action herbicides, which are intended for the complete destruction of germinating seeds and plant roots. Usually, herbicides are introduced into the bud before sowing the crop at different periods of the growing season.
Effective continuous action herbicides are “Roundup”, “Alaz”, “Tornado”, “Glysol”. Roundup is widely used in all countries of the world. It effectively fights with both annual and perennial weeds, and destroys both their underground and terrestrial parts. In addition, this substance is devoid of soil activity, which means that any culture can be sown after applying the drug. Roundup is one of the safest herbicides. It poses no danger both to the environment and to humans when used correctly. The drug, which is applied to the surface of shoots and leaves, is absorbed for six hours, and is transferred to the roots and other parts of the weeds after about 7 days. The first signs of exposure are expressed in yellowing and wilting of plants. This effect is noticeable after 10 days, and the plants die off completely three weeks after treatment with the drug.