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SECTION 1: Definition and classification of pesticides in terms of type and grouping

1.1 Introduction

History does not tell us very much about chemicals used against insects. The earliest records of insecticides pertain to the burning of sulphur as a fumigant. A variety of materials have been used with doubtful results: extracts of pepper and tobacco, hot water, soapy water, whitewash, vinegar, turpentine, fish oil, brine and many others.

Even as recently as 1940, our insecticide supply was limited to several arsenic salts, petroleum oils, nicotine, pyrethrum, sulphur and hydrogen cyanide gas.

In this section we will discuss the following topics:

  • The RSA Classification Code
  • Definition and Classification of Pesticides
  • The major groups of insecticides
  • Formulations
  • Strategies to manage resistance

The following SABS Code of Practice is applicable: SABS 0228 The Identification and Classification of Dangerous Substances and Goods.

1.2 The RSA classification code

From 1992 South Africa changed to a new system for classifying and labelling all kinds of pesticides.

The new system makes provision for classifying formulated products according to the hazard the product holds for the user and not the toxicity of the active ingredient as it was the case in the old system. This step brings South Africa in line with international standards and uses as prescribed by the World Health Organisation (WHO) and the United Nations.

The matter is fully discussed in the publication of the Department of Agriculture and AVCASA. The title of this publication is "Guidelines for the RSA classification code of agricultural and stock remedies and associated labelling practices". The publication is obtainable from these two organisations.

According to the new RSA classification system, a product will be clearly labelled as seen in the table that follows. Labels will also be easy to read because the smallest print size must be 8 point (about 1.5 mm).

A very important new feature of the labels will be the use of pictograms on the sales panel (see pictures depicting pictograms in this section). The purpose of these pictograms (pictorial symbols) are to present symbolically potential dangers and precautionary measures to less literate users of pesticides.

1.2.1 Pesticide labels

According to the new RSA classification system, a product will be labelled as follows:

1.2.1.1 Colour coding

Poison Group Warning statements on container Colour of band* around container
Group IA Very toxic RED
Group IB Toxic RED
Group II Harmful YELLOW
Group III Caution BLUE
Group IV No warning statements GREEN

Table: Group classification and warning statements on labels.

A special feature of the new system is the use of a colour band around the sales panel at the bottom of the label, in the above-mentioned colours, to indicate the different poison groups (see ‘Hazard Classification” a little further on in this section).

Note: The RSA codes will be discussed in more detail later in this module.

1.2.1.2 Information on the label

The label of a pesticide container is supposed to supply you with the following information:

1. How to mix the pesticide
2. How to apply the pesticide
3. What special precautions are necessary with this product
4. Where and how to store the product
5. Where and how to dispose it
6. Sometimes the label informs you what protective equipment to wear.
7. First aid recommendations
8. A special note to the doctor in case of human poisoning (remember always to take the label with you to the doctor in case of poisoning)

1.2.1.3 Symbols, pictograms, etc.

Examples of Symbols, Pictograms, Advice and Hazard Classification that appear on Pesticide Labels nowadays are depicted as follows:

Very Toxic/Toxic:
This symbol is used to denote Group la (extremely hazardous) and Group lb (highly hazardous) remedies. The hazard statements VERY TOXIC and TOXIC are used respectively.

Harmful
This symbol is used to denote Group II (moderately hazardous) remedies, the hazard statement HARMFUL is used. Other groups do not require a hazard symbol. Also known as the St. Andrew’s cross.

Expiry Date
This symbol is used to draw attention is used to the expiry date mentioned on the label.

Pesticide Label Pictograms and Colour Codes
Meanings of Advice & Warning Pictograms
Wear gloves
Wear boots
Wear protection over nose and mouth
Wear respirator
Wear eye protection
Wash after use
Dangerous/harmful to wildlife and birds
Dangerous/harmful to fish - do not contaminate lakes, rivers, ponds & streams
Dangerous/harmful to livestock & poultry
Not for aerial application
Keep locked away and out of reach of children
Expiry date
Meanings of Activity Pictograms
Handling liquid concentrate
Handling dry concentrate
Application
Meanings of Colour Codes
(Listed from the most (1) to the least (4) hazardous)
Very toxic: Most toxic pesticide groups (Ia & Ib). Protected equipment & clothing MUST be used.
Harmful: 2nd most toxic pesticide group (Group II). Use all precautions stated on label.
Caution: Use carefully and use protection (Group III)
Relatively safe (Group IV)
All pesticides are toxic. Store away from children, food or animals. Keep locked away.

1.2.1.4 Hazard classification bands

The bands will, therefore, end up looking something like this. Note that it includes colour coding, pictograms and symbols. The level of toxicity is also stated on the band.

HAZARD CLASSIFICATION

GROUP Ia

GROUP Ib

GROUP II

GROUP III

GROUP IV

These colour bands appear at the bottom of pesticide containers, indicating the level of hazard of each group.

The etiquette will therefore end up looking something like this.

Pesticide Classification, Properties and Products

1.2.2 Classification according to Target Pest

Pesticides can also be classified in terms of the target pest which is supposed to be controlled by the pesticide. This is done as follows:

Its function:

It is therefore called:

Kill Insects

Insecticides

Kill Mites

Acaricides

Kill Snails

Molluscicides

Kill Birds

Avicides

Kill Weeds

Herbicides

Control Plant Diseases

Fungicides

Kill Nematodes

Nematicides

Kill Rodents (Rats & Mice)

Rodenticides

Pesticides are also divided into groups according to their chemical structure, for example: organo phosphates or synthetic pyrethroids. More detail on this a little later in this section.

1.2.3 Classification, Properties and Products

In this section, we will discuss various groups of pesticides, their properties, and where applicable the product range. This will be done in the following order:

  • Organic pesticides
  • Inorganic pesticides
  • Modern pesticides
  • Repellents
  • Rodenticides
  • Avicides and repellents
  • Fumigants (Space treatment)