Agrochemicals are products intended for use in the production, processing and storage of agricultural products.


In most crops, the main agrochemicals used are insecticides, herbicides and fungicides however, the producer must take care to use only the agrochemicals sanctioned by the regulating authority, according to the legislation in force in his country and only use them under the guidance and recommendation of an agronomist.


According to the world convention for the use of agrochemicals, these are classified as toxicological class both for humans, as well as the ecological impacts they may cause to the environment.
The label of agrochemicals is the main form of communication between the manufacturer and the user, so it is important to read correctly all the information contained in the labels of the agrochemicals packaging.

All agrochemicals must be labeled with a label indicating their toxicological class.




      Class III


      Class IV

        Moderately toxic





 Little toxic


  Highly Toxic

Class II

   Class I

      Extremely toxic



The effectiveness of agrochemicals in controlling pests, diseases and weeds depends very much on their correct application.

The misuse of agrochemicals, in addition to jeopardizing their effectiveness, can contaminate people and the environment, so it is important to carefully read the packaging label of agrochemicals and follow the agronomist's guidelines.




The application technology is not limited to the application of the product, but rather to the interaction between several factors (crop, pest, disease, invasive plant, product, equipment and environment), seeking efficient control with low cost and minimal environmental contamination.


Main errors in the application of pesticides:


  • Inappropriate product use;
  • Deregulated equipment;
  • Incorrect dose (sub and overdose);
  • Moment of incorrect application (plant development phase);
  • Application under unsuitable weather conditions;
  • Water used to mix the pesticide in the tank is of poor quality (excess of suspended particles, PH incompatible with products, among others);
  • Stops/Blockage with connected equipment;
  • Draining and dripping;
  • Excessive area overlaps during application.



Climate conditions should be favorable to the absorption and translocation of products. In general, the climate conditions at the time of application should be as follows:

  • The minimum temperature of 10°C - The ideal of 20-30°C, and the maximum of 35°C.
  • Minimum air humidity of 60% - Ideal from 70 to 90%, And the maximum, 95%.
  • Do not carry out applications in the presence of winds with speeds below 5 km / h or above   10 km /h, on stressed plants and in the case of imminent rainfall, otherwise the treatment efficiency will be lost or crops will be damaged.

In order to know if the wind is too strong to make an application, it is possible to make a very simple and practical test, in which a sheet of paper is placed on the floor, if it moves by the force of the wind, therefore changing its position is a Sign that the wind is too strong to carry out the application of agrochemicals.

Application to stressed plants reduces the absorption and translocation of the product and can reduce the metabolism of the molecules by the crop, reducing the selectivity in the case of the herbicides.
The occurrence of rain soon after the application can wash the molecules of the product off the surface of the leaf of the plant and prevent its absorption.

Some herbicides require up to six hours of rainfall after application to be absorbed in sufficient quantity to be efficient.

The low relative humidity causes dehydration of the cuticle and the consequent rapid evaporation of the drop on the surface of the leave, causing crystallization of the product on it, thus hindering the absorption of the molecule.

High temperatures can cause volatilization of the molecules and increase the evaporation of the droplets. On the other hand, low temperatures can reduce plant metabolism and hinder absorption.
Application in the presence of wind at speeds above 10 km / h may cause drift and droplets will not reach the target and may reach sites with sensitive cultures. The drift consists of the movement of drops or steam to non-target locations, causing damage to nearby crops. The main factors that affect drift are:


  • Droplet size
  • Height or distance between target and nozzle,
  • Wind speed,
  • Speed of application,
  • Method of application, and
  • Product volatility.


It is common, for example, to observe toxicity of certain formulations (2,4-D Ester) affecting neighboring areas, especially when this herbicide is applied under inadequate conditions.

The ways to reduce drift are:

  • Apply at appropriate times
  • Apply during the right environmental conditions stated earlier above
  • Use appropriate formulations;
  • Proper calibration of spray nozzles, and
  • Use proper operating pressure.

One factor that the farmer must always consider is to respect the period of time between the last application of agrochemicals and the harvest, determined on the label of agrochemical packaging.


Success in pest and disease control depends on the choice of the right product and its correct application. The pesticides are sprayed onto the soil or plants and to ensure that the active ingredient reaches the entire target surface, it is necessary that the equipment is evenly distributing the correct amount of product per area.

The calibration of the equipment of application of agrochemicals is very important, since the equipment is not identical and suffer wear over time. Small variations can cause large differences in the application of agrochemicals and may cause ecological impacts and inefficient control.

The amount of active ingredient applied must be correct to avoid failure of control or crop damage. To do this, before starting the application, it is necessary to carefully review the equipment to be used. The nozzles should be examined individually to assess wear and alignment. In addition, the volume of chemical to be applied, the number and size of the droplets, the working pressure of the nozzles, the dosage, the dilution, the agitation and the need for the addition of adjuvants should be checked carefully.
The producer should always consult an agronomist to define the equipment's regulation and define, for example, the type of nozzle to be used, in order to evenly distribute the correct dose of the product in the area, avoiding waste and losses in yield due to toxicity caused to the crop. The occurrence of errors in the applied dose usually presents / displays reduced possibility of correction and are the main reason for the majority of the application’s failures.


3.1   Cleaning the nozzles:

Instruments such as needles, wires, pocket knives, wood chips to unclog nozzles should not be used. The correct way is to use an instrument that does not damage the nozzle hole, such as a nylon bristle brush (toothbrush), a nylon wire or compressed air. Never blow or place eyes near nozzles.

3.2   Nozzle exchange:

It is recommended to change the nozzles when the flow rate exceeds the flow rate of a new nozzle by 10%. When this happens, the whole assembly should be replaced. When it reaches more than 10% of wear its characteristics can hinder the application resulting in poor control and toxicity to the plants or environment. It should not be forgotten that the cost of waste of pesticides and possible toxicity to the crop could be much higher than the cost of replacing the nozzles.


3.3   Adjusting the sprayer:

Sprayer calibration should be performed periodically due to the natural wear of some components, such as nozzles, or due to loss of calibration from repeated usage and other field conditions.
In the calibration of sprayers, the steps to be followed are:

  • Use personal protective equipment (PPE);
  • Fill the sprayer with clean water
  • Activate the spray assembly and assess leaks
  • Determine the distance between nozzles, in meters
  • Determine the speed of work on a level ground, with characteristics similar to the spraying conditions on the field.


To determine velocity, a distance, preferably equal to or greater than 50 m, should be measured. Stroll the measured distance and note the time spent (in seconds). Drive the sprinkler and collect the water sprinkled in equal time to the time spent to travel that distance. Repeat this operation on several nozzles. Obtain the mean and calculate the flow rate, which can be determined with the Formula:

Flow (L / min) = 0.06 x volume collected (ml) / time (s)





























































  1. Personal Protection

Always use personal protective equipment (PPE) when handling agrochemicals





To avoid contamination of equipment and worker exposure, a logical sequence should be followed to remove PPE.

Note: The first procedure to be performed before removing PPE is to wash the gloves with soap and water before being removed from the hands to decontaminate them.

Gloves should be worn inside the overall sleeves when applying on low targets and out of the overall sleeve when applying on high targets.


The boots should be worn inside the overall, to prevent product ingress from draining.
If PPE is composed of pants and shirt, always wear the shirt on the outside of the pants.

5.1 Order to dress and remove IPE:













Nose mask














Nose mask

The routes by which one can get poisoned by agrochemicals are:

  • Oral (mouth);
  • Nasal (nose);
  • Ocular (eyes);
  • Dermatological (skin).


5.2   FIRST AID:

In case of an agrochemical accident, the exposed person should receive medical care immediately, never do what you do not know or have not been trained to do.

The packaging of the product, label or prescription, should be presented to the physician in order to aid in the diagnosis and treatment.

In case of:


  • Ingestion (Mouth): Do not induce vomiting of the person who has ingested agrochemicals. But if the vomit occurs spontaneously the infected person should be lying on the side. Never administer food or drink to the victim.


  • Inhalation (Nosed): If the pesticide is inhaled the person should be taken to an open and ventilated place.


  • Eye contact (Eyes): Flush eyes with plenty of water for at least 15 minutes. If only one eye has been reached, care should be taken to prevent the water used to clean the eye from reaching the other eye.


  • Contact with skin (Skin): Remove contaminated clothing and wash skin with plenty of running water and mild soap.






Humberto Da Silva Da Rosa

Agronomist / Farm Operations Manager