Cover Image
close this bookManual on the Prevention of Post-harvest Grain Losses (GTZ)
close this folder8. Pest control using insecticides
View the document(introduction...)
View the document8.1 Insecticides
View the document8.2 Application techniques
View the document8.3 Calculating the dosage of insecticides in stored product pest control
View the document8.4 Precautionary measures
View the document8.5 Equipment
View the document8.6 Further literature

8.4 Precautionary measures

Insecticides constitute greater or lesser dangers to humans and to all other living organisms. In order to minimize the risk of damage being caused, precautionary measures must be strictly adhered to when dealing with insecticides. Even apparently inconsequential violations of safety regulations may have serious results, many of which will not be immediately recognizable.

8.4.1 Storing Insecticides

When storing insecticides, it is imperative:

- that any danger to humans, animals or the environment be excluded
- that the insecticides remain effective as long as possible


Figure 115

The following points must therefore be observed:

- Keep insecticides locked away so that no unauthorized persons have access to them! For small amounts, a poison cabinet in a well-ventilated room will suffice; a pesticide store will be necessary for larger amounts.
- Store insecticides away from other commodities and never in offices or other rooms where people often spend time!
- Store insecticides only in their original packaging in order to prevent any possibility of confusion! Never fill insecticides into empty bottles or tins!
- Store insecticides in cool, dry and shadowed places!
- Purchase only amounts which can be expected to be used up in a single storage period. Especially dustable powders degrade fast under tropical climate conditions and loose their effectivity. Additionally this practice allows to change active ingredients regularly in order to prevent the development of resistance.
- The 'first in - first out! 'rule must always apply to insecticides.


Figure 116

8.4.2 Handling insecticides

When treating produce with insecticides, it is particularly important that the user is protected. Due to the great responsibility connected to this activity, treatment must only be performed by people who are sufficiently familiar with techniques and possible dangers. When less-qualified personnel apply insecticides, they must be instructed and supervised by a qualified technician.


Figure 117

The following rules must be observed:

- Always read the label and follow the manufacturer's instructions!
- Pay attention to the warning signs on the packaging and take them seriously! Highly toxic products bear the "skull and crossbones" symbol. Less toxic ones bear a cross:
- Simple graphic designs without words (pictograms) have been devised to communicate key safety informations to people of varied levels of literacy. Their meaning is shown on the next page.
- Preplan for emergencies: inform a nearby doctor about chemicals used, be aware of first aid measures and always have plenty of water and soap and medical charcoal at hand!
- Check that the equipment used for applying the insecticides is in good condition (dusters, sprayers, fogging machines)!
- Mix spraying liquids in the open air, not in the store!
- Avoid any contact with the insecticides!
- Do not inhale any insecticide vapours!
- Never use your hands to mix insecticides! Always use a clean stick!
- Never use your mouth to blow into blocked nozzles!
- Always wear protective clothing when mixing and applying insecticides!


Figure 118


Figure 119

Protective clothing consists of:

· Overall (made of light cotton material in the tropics) or trousers and long-sleeved shirt
· Hat (preferably with a rim)
· Respirator or a face shield with a fine dust filter
· Rubber gloves
· Wellington boots or firm leather footwear (no sandals)


Figure 120

- Do not drink, eat or smoke when working with insecticides
- Do not drink any alcohol either directly before or directly after insecticides, as this accelerates the body's intake of toxic substances.
- Use buckets solely for mixing insecticides and never for any other purpose, not even if they have been thoroughly cleaned!
- Never spill any left-over spray mixture!
- Only mix up as much spraying liquid as required in accordance with the calculated dosage. Small left-over amounts of the mixture can always be used for places in the store which are particularly endangered or for treating empty pallets.
- Dispose of all empty insecticide packages! They still contain traces of the insecticide even after being thoroughly cleaned.


Figure 121

The safest way of disposing is by destroying them (crushing cans, cutting up plastic containers, breaking bottles). Bury them in waste land, far away from wells, settlements or cultivated areas.

It is not advisable to burn them, as dangerous toxic gases may be produced on doing so.


Figure 122


Figure 123

- Thoroughly clean all material and machines used! Rinse spraying equipment, buckets, measuring cups, etc. using plenty of water.
- Wash protective clothing with sufficient soap (or washing powder) and water! Wash separately from other clothes!

Take care that wells or other water sources do not become contaminated when you wash your clothes!

- Take a shower or wash thoroughly after using insecticides for treatment!
- Always put on clean clothes after washing!
- If necessary, fix warning signs (e.g. after fogging) and lock buildings which have been treated to prevent any danger to other persons!

8.4.3 Poisoning and First Aid

If insecticides are used correctly, poisoning is not likely to occur. Most accidents are due to carelessness and disregarding rules and regulations.


Figure 124

Contamination with insecticide will take place:

- by swallowing (oral contamination)
- by absorption through the skin (dermal contamination)
- by inhaling the fumes of insecticides (respiratory contamination).

In addition, insecticides may directly enter the bloodstream through open wounds.

A distinction is made between two types of poisoning:

· Acute poisoning, when symptoms can be seen after absorbing the insecticide a single time.
· Chronic poisoning, when symptoms do only become apparent after absorbing the insecticide a number of times. Chronic poisoning may not be detected in some cases until years later.

Depending on the type of contamination, the toxicity, the amount absorbed, the insecticide formulation and the constitution of the person affected, the following symptoms may appear in varying degrees:

Should any of these symptoms occur, even slightly, first-aid treatment should be given immediately and the person concerned should be taken to the nearest doctor as soon as possible. Note that severe acute poisoning can lead to death!

The following first-aid measures should be carried out without any delay in the case of poisoning:

Slight poisoning

Moderate poisoning

Severe poisoning

Dermal contamination: irritation, perspiration, headache, nausea, dizziness, fatigue, weakness

excessive perspiration, rapid pulse, fatigue, nervous distress, slurred speech, confusion

convulsions, loss of consciousness, loss of pulse, respiratory failure

Eye contamination: irritation, watering

blurred vision, widened or narrowed pupils


Ingestion: diarrhoea perspiration, loss of appetite, irritated vomiting, trembling and mouth and throat

nausea, stomach cramps, extreme salivation, loss of pulse, twitching of muscles

convulsions, respiratory failure, loss of consciousness respiratory failure,

Inhalation: difficulty in breathing, of coughing

convulsions, loss chest pain

pulse, loss of consciousness

Skin contact:

- Remove any contaminated clothing!
- Wash the affected part of the body with plenty of water and soap!
- Should there be no water immediately available, wipe the insecticide off using a cloth and look for water!
- if the insecticide has come into contact with the person's eyes, rinse under


Figure 125


Figure 126

Inhalation or swallowing:

- Put the person affected in a shady place, open any tight clothing and lay him in a comfortable position until there is a possibility of taking hint to a doctor!
- If the person affected is unconscious, lay him on his side and take care that he is able to breathe freely (clear the respiration tract if necessary)!


Figure 127


Figure 128

- Make any affected person who is not unconscious vomit (by putting his fingers down his throat or giving him salt-water to drink (I teaspoon of salt in a glass of water) in order to remove any toxic substances still in his stomach!
- Apart from water and, if available, activated carbon, do not give the affected person anything to eat or to drink! Water will dilute any toxic substances ingested (important for caustic substances) and activated carbon will absorb most toxic substances.

Never offer affected persons eggs, milk, alcohol, etc! All of these substances accelerate the body's intake of toxic substances.


Figure 129


Figure 130

- In every case of poisoning or suspicion of poisoning, visit a doctor, even if the symptoms are not present! Symptoms often do not appear until several hours later, and important time may be lost for treatment.
- Take the packaging or the label of the insecticide with you in order to provide the doctor with all necessary details!