Responsible Pesticide Use: Module 2

 

Module 2: Basic Approach to Responsible Use of Pesticides

Module overview

Welcome to Module 2. In the previous module we raised some risks that can be posed by pesticides and the FAO Code of Conduct that is designed to address these problems. In this second module we would like to give you an idea of a basic approach to minimising the risks. In the lessons included in this module we will cover the following 7 basic responsible use rules:

  1. Apply Integrated Pest Management principles as the first choice.
  2. Read, understand and obey the pesticide label.
  3. Only use pesticides for which the proper Personal Protective Equipment is available, and use it properly.
  4. Handle, mix and apply pesticides according to label instructions.
  5. Know poisoning symptoms and first aid procedures.
  6. Observe recommended withholding periods (pre-harvest intervals) to ensure that harvested crops do not exceed maximum residue levels (MRLs).
  7. Follow recommendations when transporting, storing, disposing of pesticides and cleaning up any pesticide spills.

Rule 1: Apply Integrated Pest Management Principles as the First Choice

Integrated Pest Management, or IPM, is characterized by management of pests so they do not cause economic losses, rather than total elimination of pests. IPM is a way to keep pest densities below the level where they ‘eat’ into farmer profits. IPM practitioners use a holistic approach to managing pests, combining or ‘integrating’ different ideas and methods from a broad range of disciplines into a comprehensive program. Agricultural professionals and farmers who understand and use IPM have a powerful tool at their disposal. There are several definitions of IPM. One that we like and use in our agLearn program is as follows:

“IPM is a set of management activities that farmers implement to maintain the intensity of potential pests at levels below which they become pests, without endangering the productivity and profitability of the farming system as a whole, the health of the farm family and its livestock, and the quality of the adjacent and downstream environments.” (John Wightman, 1998)

One of the most fundamental premises of IPM is also one of the most important concepts of responsible use. This is that every effort should first be made to prevent the need for pesticides and that they should only be used as a last resort. Prevention, preventing the occurrence of pest problems before they can cause economic damage or require an intervention, is by far the most preferred and most responsible tactic. The concept is illustrated in the cartoon below in which IPM is represented by the soccer team on the right, who are up against the pests on the left. The IPM team use knowledge (the IPM book), grow resistant varieties (best seeds) and make use of the control of the natural enemies of pests (predators and parasitoids). The last line of defence, the goalkeeper, is the sprayer who represents the use of pesticides.

Further information

http://www.fao.org/agriculture/crops/core-themes/theme/pests/ipm/more-ipm/en/

For additional information on health and environmental risk assessment:

Rule 2: Read, Understand and Obey the Pesticide Label

By law in most countries, all pesticides sold must have a label, and users must read and obey it. In most countries, for example, it is illegal to use a pesticide on a crop unless the crop is listed on the label. It is also illegal to exceed the given rate of application on the label. Reading and understanding the label should be your starting point for responsible use once a decision has been made to use a pesticide as a control tactic within your IPM programme.

The label should give you all the information you need for observing the rules of responsible use. It will tell you how dangerous (hazard category) the chemical is by hazard classes (PDF). The label will give you some idea of what personal protective equipment you should use (precautionary statements), often through the use of pictograms. It will provide information on handling, mixing, and application and may include recommended equipment. The label should also tell you the last date before harvest that it is safe to apply the chemical. This is known as the pre-harvest interval or the withholding period. The label will usually give you advice on what to do if the chemical is accidentally swallowed or spilled.

Further information

Rule 3: Only Use Pesticides for which the Proper Personal Protective Equipment is Available and Use them Properly

In the first module on health risks of pesticides we presented a simple formula – Risk = Toxicity x Exposure. This relationship tells us that one way to decrease health risks is to reduce exposure to chemical pesticides. Avoiding exposure is the primary function of Personal Protective Equipment (PPE).

Choosing the proper PPE for any activity involving pesticides starts with reading the label. By law, all legally registered pesticides must tell the user if and what PPE’s should be used. This information is usually in the form of Precautions statements on the label and many manufacturers also use pictograms, to tell users what PPEs should be used when using their products.

There are 2 critical rules associated with PPE’s. One is that if the required PPE’s are not available for a particular product, or if they cannot be used for various reasons (e.g. too hot, too expensive, etc.), then the pesticide in question should not be used. The second is that if PPE’s are available and appropriate then they should be used correctly.

A considerable amount of information on the proper use of Personal Protective Equipment (PPE) has been developed, collected and published by several organizations. Some examples can be accessed at the following websites:

Rule 4: Handle, Mix and Apply According to Label Instructions

Handling is any activity that involves exposure to a pesticide. This includes mixing, transporting, storing, disposing, applying, or working on pesticide equipment. Of course, the primary concern when handling pesticides is for personal safety and there are a number of safety steps that any operator should make whenever pesticides are handled. Before applying any pesticide, he or she must decide whether the pesticide is really needed. If the answer is yes, the operator must minimize environmental risks by analyzing the situation and making informed decisions. Some of these decisions include what pesticide to use, what formulation of a particular pesticide is best, what application procedure will give the best result with the least risk, what is the best time to apply and how much pesticide is needed. Responsible use involves selecting the least toxic and least persistent pesticide that will give the desired result. It also involves following all label recommendations when mixing, loading or applying any pesticide.

A key handling concern is the selection of the most appropriate application equipment, which commonly means what type of sprayer. When equipment is selected the user should consider the type of pest, the pesticide that needs to be applied and the recommended method of application. Additional considerations are the size and type of area to be treated. Proper maintenance of application equipment is important because the applicator wants to be sure to apply only as much as is necessary and only put it where it will achieve the desired effect. Applying too little is a waste of the product, puts pesticide into the environment unnecessarily and can accelerate the development of pest resistance. Applying too much raises costs and increases risks. Applying pesticides outside the target area is again an uneconomical waste of product and poses unnecessary risks.

When thinking about pesticide application it might be helpful to remember the “Three E’s” of application. These state that application needs to be:

  • Effective
  • Economical, and
  • Environmentally friendly.

Further information is given in the Guidelines on Good Practice for Ground Application of Pesticides (FAO) at http://www.fao.org/docrep/006/Y2767E/Y2767E00.HTM

The FAO Plant Production and Protection Division (AGP) documents on sustainable production at http://www.fao.org/agriculture/crops/core-themes/theme/pests/en/

At http://www.aglearn.net/resources/resUse/pestAppMeths.pdf the AgLearn booklet on Choice of Pesticide Application and Methods can be downloaded.

The University of Nebraska–Lincoln Pesticide Safety Education Program publishes several manuals on various aspects of pesticide use, and can be found at http://pested.unl.edu/psephome

Several US universities such as Michigan, Colorado and others publish guidance on how to calibrate spraying equipment, but one of the easiest approaches is to set up your sprayer with the nozzles that are recommended, then measure a small area and mark it. If you mark out 10 metres x 10 metres, the area will be 1/100 of a hectare. For backpack sprayers this would be OK, but for tractor-mounted machinery you would need a larger area, say 50 metres x 50 metres (1/4 hectare). Fill the sprayer with water (not spray liquid) and then spray the area you have marked out. Then find what volume you have used by looking at the marks on the tank or by measuring the volume to re-fill the sprayer. It is then easy to calculate your volume application rate. Once you know this, you can calculate how much of the concentrated pesticide to put into the spray reservoir tank. For example, if your volume rate was 400 litres per hectare and the pesticide label recommended 2 litres of product per hectare, the 2 litres must be mixed into 400 litres of spray liquid. If your volume rate was 500 litres per hectare, the 2 litres of concentrated product would need to go in 500 litres.

Rule 5: Know Pesticide Poisoning Symptoms and First Aid

As mentioned earlier, most pesticides are applied in order to kill, harm or repel a pest. As many pests have biological functions similar to humans it is not surprising that many chemical pesticides can also make people ill. Of course, the most important thing to remember when dealing with pesticides is that prevention is the best protection and all efforts should be made to avoid exposure in the first place. To prevent accidental exposure you should:

  • make sure the labels can be read
  • read and follow the label instructions
  • keep all pesticides out of reach of children and animals
  • store pesticides safely in a locked area
  • dispose of unused pesticides properly
  • keep pesticides in original containers with labels intact – decanting into other bottles is particularly dangerous
  • never re-use pesticide containers for food or drink
  • wear all the personal protective equipment the label suggests
  • destroy any food (or other items) you suspect may have been contaminated by pesticides
  • do not eat, drink or smoke when using pesticides
  • provide good ventilation when storing and using pesticides

We all know, however, that accidents happen – no matter how careful we are. People who use or work around pesticides, or people like participants in this on-line learning who are working with farmers who are using pesticides, must therefore be familiar with the signs and symptoms of poisoning. They must also know appropriate first aid procedures that should be applied while waiting for medical help. First Aid information is generally printed on the pesticide label.

The AgLearn site gives Information on what to do if something goes wrong, and someone is affected by pesticide.

The first thing is to avoid risking your own health or other bystanders by acting rashly. Then remove contact exposure removing the person from the scene of spillage or other contamination. Avoid further skin contact and remove contaminated clothing and use large volumes of water to wash away the pesticide. This is especially important if the eyes are touched by chemicals.

First Aid, including signs and symptoms of poisoning are dealt with in the file given above. In almost all cases the person who has been contaminated with pesticide will need to be taken to a medical facility for a check-up. It is a good idea to have an emergency phone number on your mobile when working with chemicals.

Further information

Rule 6: Observe Good Agricultural Practice Including Recommended Withholding Periods to Ensure that Harvested Crops Meet Maximum Residue Levels

One of the primary regulatory responses to promoting responsible pesticide use has been to establish maximum residue levels (MRLs) which are the legal maximum quantity in mg/kg, of a pesticide present in food.  Any agricultural product with residue levels above this limit may not be legally sold or traded. This MRL mechanism helps to verify that products have been used according to the label, and ensures that health risks are minimised. MRL’s are established as a part of the approval process for pesticides, and establishing these values involves performing trials to determine what levels of residues are present at harvest, when the product is used as directed (by following label instructions). The residue levels found in these trials help regulators to decide the value of the MRL, and the figures are usually incorporated into national food laws. Any produce with levels above the MRL is considered to be illegal and must be destroyed.

There are generally large margins of safety between allowable exposure in the diet and levels of exposure which could cause health concerns. The reason for setting and enforcing MRLs is not so much to establish safety or health limits, but to make sure that pesticides are used responsibly and according to the label, and enable national and international food trade to take place.

Pesticide residue levels above the MRL may result from several practices:

  • using a pesticide (or combinations of pesticides) not registered for the particular crop,
  • over application of chemicals (never exceed the application rates or the total number of applications recommended on the label), or most commonly,
  • chemicals applied too close to harvest time.

In order for a grower to avoid having produce rejected, or in some cases being fined because of illegal residue levels, registration authorities have determined what are known as withholding periods. A withholding period is defined as the period of time that must elapse between the last application of a pesticide and:

  • harvesting of plants;
  • grazing or cutting for stock food;
  • consumption by a human or animal after post-harvest use.

Most pesticide manufacturers include recommended withholding periods on the product label, generally under ‘Directions for Use”.

There may be a temptation use residue issues to manipulate the market when countries or regions are in competition for sales, and sometimes MRLs have been used as barriers to trade for economic reasons, rather than food safety reasons. To prevent or reduce such conflicts an international body created under the Food and Agriculture Organisation of the UN, and the World Health Organisation, and known as ‘Codex Alimentarious’ was charged with setting international residue standards for food including chemical residues in food. If any such conflict occurs it is the role of the World Trade Organisation (WTO) to intervene using its Dispute Settlement system.

Participants interested in MRLs and the international bodies that oversee trade should visit the links below:

Rule 7: Follow Label Recommendations when Transporting, Storing, Disposing of Pesticides and Cleaning Up Pesticide Spills

Of course, the actual application of pesticides on the farm is only one of several activities in which people need to observe responsible practices. Safety must also be a prime concern when transporting pesticide products from the manufacturing site to the retailers and then on to the farm. After production, during their journey to users and upon reaching their final destination they will need to be safely stored. On many occasions pesticides, or their containers, will have to be disposed of in a manner that will cause the least impact to human health or the environment. Finally, accidental spills do occasionally happen, and when they do, they need to be treated in an appropriate safe manner to minimise the risk.

Below are links to a number of documents that provide detailed information on all of these activities. Participants may also want to go through the following agLearn tutorials (the first three links) below.