PESTICIDE APPLICATION TECHNIQUES
IN WEST-AFRICA
Gert van der Meijden
Food and Agriculture Organization of the United Nations
FAO Regional Office for Africa
Accra, Ghana
and
Agricultural Engineering Branch,
Agricultural Support Systems Division,
FAO, Rome, Italy
August 1998
Note: The views expressed in this paper do not necessarily reflect the official views of FAO or its Member Countries
2. Pesticide application techniques: the current status
3. Perceived problem areas in pesticide application techniques
3.1 Malpractice and Lack of Safety Measures
4. Governments' policies and research
5. Conclusions and recommendations
Both safety and effectiveness of pesticide use are to a large extent determined by the technical state of the equipment that is used for application. In the majority of cases pesticides are applied using either a nozzle or a spinning disc to disperse the spraying liquid into a spraying cloud of small droplets. Both of these parts of the equipment but also others represent relatively sophisticated pieces of engineering that require not only certain levels of maintenance but also of training and knowledge of the user. Knowing what exactly the problems are in these areas will first of all help us to find entries for improvement of the current practice of pesticide application to increase not only effectiveness but also safety of the user. Secondly, an increase in effectiveness will result in a reduction of usage representing a decrease in costs and in environmental hazard.
The question could be asked if it serves a purpose to try to improve the current practice of pesticide use while there is an international drive to cut down on it. To answer this question we have to consider the following; pesticide use has increased in developing countries ever since its introduction and it still is. Next to traditional methods such as tillage, burning and crop rotation, it still represents a vital pest control strategy for farmers in developing countries. Thanks to techniques such as Integrated Pest Management and the use of crop varieties with higher resistance, the current growth of use will be declined. Thus the curve of pesticide use will bend downwards but still show a rising trend. We can therefore safely state that African agriculture is still dependent on pesticides to attain acceptable levels of crop production. Furthermore pesticides have over the years become more powerful and more specific and therefore demand for a higher standard in application technique. For as long as these two situations prevail it does serve a purpose to make an effort to apply the pesticides needed with an efficiency as high as possible, as safe as possible and with a minimum of environmental hazard. And, as stated before, improving the practice of pesticide application will, through improved efficiency, contribute to the drive to diminish the use of chemicals. This paper tries to identify the possible areas of intervention to attain this situation, concentrating on the current practice of pesticide application and the equipment that is used in the process.
This study was carried out by the Agricultural Engineering Branch of FAO through the FAO Regional Office for Africa. A questionnaire was elaborated which was sent to 110 addresses in 17 West African countries. In total 25 questionnaires were returned which is a rate of response of 23%. From 15 out of 17 countries, at least one questionnaire was received. The countries that did not respond are Cap Verde and Sierra Leone. The results of the questionnaire have been combined with a literature study.
Pesticide application equipment has been introduced into the African farming systems, together with the pesticides to be applied, ever since they were used in the industrialized countries. Practically all different techniques available have, at a given point in time, been introduced more or less successfully. Of the three major groups of application equipment, e.g. portable, tractor mounted and aeroplane mounted, only the portable equipment is used on a significant scale in West Africa.
From the 25 questionnaires that were returned, the following use of equipment was identified. Since respondents reported various varieties of the same type of equipment more than once, the total can add up to more than 25.
Knapsack sprayer (reported 27 times)
There are two major types of knapsack sprayers:
Lever-operated knapsack sprayers
These are the most widely used small-scale sprayers in developing countries. Through a hand-operated pump and a nozzle/nozzles, they produce a wide range droplet size spectrum and use about 200 l/ha.
Compression sprayers
With these sprayers the whole of the container that contains the spraying liquid is pressurized. Sizes range from less than 5 litres (in which case they are hand-carried) to over 10 litres.
In practically all cases this was reported as the most important application technique. The underarm lever operated type is most popular but shoulder pump sprayers and compression or pneumatic sprayers were also mentioned. Knapsack sprayers are used to apply any kind of pesticide (e.g. mostly insecticides, followed by fungicides and herbicides). Water volumes range from 100 to 400 l/ha. Most likely because of the costs involved, a sprayer is more often used on cash crops such as cocoa, maize and cotton, and also on garden crops and to a lesser extent on the staple food crops.
Spinning disc sprayer (reported 13 times)
Spinning disc sprayers use a plastic rotating disc, powered by batteries, to disperse the spraying liquid into very small droplets. Application volumes can be as low as 3 litres per ha which is a major advantage in cases of water scarcity and also their relative simple technique and ease of use have contributed to the widespread use of spinning disc sprayers. Cauguil (1985) reports that over 80 per cent of farmers' cotton crops in francophone Africa are sprayed with hand-held, battery-driven spinning disc sprayers. Drift of the spray cloud and total dependence on air movement for distribution of the spray cloud is a disadvantage. The concentration of pesticide in the spraying liquid can be very high (up to 100%) which increases the risks of phytotoxicity and intoxication of the operator.
Notwithstanding the disadvantages, results show that spinning disc sprayers are indeed second in use after the knapsack sprayers and were reported 13 times. Mali, C�te D'Ivoire, Burkina Faso, Togo, Senegal and Nigeria report the spinning disc sprayer to be even more commonly used than the knapsack sprayer. Insecticides are the most common pesticides for a spinning disc sprayer, followed by herbicides. The sprayers are most widely used in cotton and garden crops, followed by niebe and other food crops.
Mist blower (reported 12 times)
Mist blowers belong to the group of air-carrier sprayers that, as a common feature, provide an air stream in which droplets are projected towards the target. Mist blowers produce large spray clouds and are therefore often used in tree crops. The spraying volume used is relatively low; 20l/ha.
Twelve respondents reported the use of it. Cocoa and citrus are the crops it is used in most but also food crops were mentioned. Mist blowers are generally used for insecticides.
Others
On a less significant scale there is the use of other methods such as; sprayers mounted on tractors or other vehicles in industrial crops, rice, cotton and cowpea (reported 6 times), different ways of applying powders (i.e. a plastic bottle with holes (for post harvest), a hand operated duster and plastic bags containing insecticides)(reported 5 times), the use of a fogging machine (reported twice) and of post harvest application by sprinkling pesticides by hand (reported once).
To explore the problem areas in pesticide application techniques, as the specialists working in the field in West Africa perceive them, the questionnaire contained three questions to elaborate on this subject. Classifying and grouping the complex network of causes and consequences gives the results as shown in figure 1: Problem Areas in Pesticide Application Techniques on the next page. The numbers between brackets is the number of times that that particular item was mentioned in the questionnaire.
Figure 1: Problem areas in Pesticide Application Techniques
It is clear that application of pesticides is a field that requires efforts to improve the current situation in order to diminish intoxication and environmental damage, and to improve effectiveness of pesticide use. The problems centre around the malpractice in pesticide application due to ignorance and the bad state of the equipment.
Notwithstanding efforts from many governments to improve the situation on safety and pesticide use, the lack of safety precautions still causes many contaminations and poisonings in the field. Poisoning of humans (in most cases the operator) remains the most often raised and the most salient consequence of malpractice in pesticide application. This is primarily caused by the lack of training and the inherent ignorance of operators on the hazardous effects of pesticides, in combination with the fact that protective materials may not be available, not affordable, too hot to wear or, as one respondent replied, too ludicrous to wear. One of the major problems here is that investments in protective clothing, masks or gloves only pay back in terms of health and well being, not in financial terms. Farmers, not fully aware of the hazards of pesticide contamination, with low income are very unlikely to pay for such items, especially in cases where they are scarce. Nigeria reports that farmers do not wear any protective materials at all, no matter what pesticide is being applied. Illiteracy further adds to the problems whereas farmers cannot read instructions nor cautions on the product label.
Pesticides have over the years become more specific and generally less toxic to humans but still hardly any pesticide is harmless to humans. Moreover, many of the products classified by the World Health Organization in category I, signifying that they are highly or even extremely toxic (WHO, 1992, as in Friedrich, 1996), are still used in developing countries. The figures that illustrate what the situation is like are horrifying; some sources report up to 25,000,000 cases of poisoning per year worldwide (Knirsch, 1994, as in Friedrich, 1996). WHO reports 500,000 cases of acute poisoning every year. With a mortality rate of only 2% this would mean there are 10,000 fatalities every year, which mostly take place in developing countries. Legislation and the actual implementation of the legislation on the use of these pesticides could bring improvement in this situation.
Ignorance on the side of the farmer brings about health hazards but also contributes to misuse and inefficient application of pesticides. Problems that were mentioned specifically in the questionnaire include: the inability to distinguish one pest from the other, usage of the wrong type of nozzle, mixing of pesticides that should not be mixed and using ULV formulations for knapsack applications.
ULV applications are a more `sophisticated' way of applying pesticides that demand more knowledge and skills from the user and also increase the risks of contamination. The spray liquid contains high concentrations of the active ingredient and walking through the spray cloud and through the treated foliage easily contaminates the operators' clothes and skin with high doses of pesticide. Phytotoxicity through overdoses also occurs more easily with ULV applications.
The first party to enlighten farmers on safety precautions as well as general knowledge on pesticide application is the front line staff of the extension system. In so many cases however, these systems are limited in output, understaffed and ineffective. Extensionists generally lack support, are poorly trained in pesticide management, lack motivation, and there seldom is any problem follow-up. One respondent mentioned also that extensionists are generally trained more on which pesticides should be used for which pest rather than on the equipment and application techniques. Given the fact that extension workers will more often than not be unavailable for advice, the farmer relies on the vendor of the product and the product label for information on how to apply the pesticide and on safety precautions. The major producers of pesticides have in most cases not taken the responsibility to provide training for their retailers to enable them to assist the end users with advice. This, in combination with illiteracy leaves the farmer in an `information vacuum' concerning information on the pesticides that he or she is using.
Youdeowei (1989) reports stunning examples of pesticide misuse:
- Gammalin 20 and other pesticides poured into rivers and ponds for killing fish which is then sold for human consumption;
- Rodenticides used in baits to kill wildlife which are later sold to humans for consumption;
- Aerosols and powder formulations applied to dried fish, grains or kolanuts to preserve these products;
- DDT powder and DDVP aerosols applied directly to the heads of humans infested with head lice.
Farmers generally have a tendency to use more pesticides than really needed. One reason is that a farmer desires to reduce risks. Secondly, the perception by farmers and extensionists of yield losses due to pests is often higher than actual losses. This induces the farmer to use large quantities of pesticides that have only marginal or no benefits in terms of yield gains or may even induce pest outbreaks. Also, in many countries, the overuse of pesticides was and still is encouraged by pesticide subsidies (Alexandratos 1995).
The answers show a high incidence of mismanagement of equipment such as incorrect handling, off-season storage that damages the equipment, leaving mixed pesticides in the sprayer overnight, damaging the disc of spinning disc sprayers etc. Farmers reportedly also occasionally damage nozzles by enlarging the hole to increase the flow. Training on the basics of pesticide application could largely improve the situation.
It is the combination of `active' mismanagement and the `passive' lack of maintenance that make that the average piece of pesticide application equipment in West-Africa is in a bad state (reported 10 times). The respondents find the lack of maintenance to stem from two important shortages: the lack of spare parts (because of unavailability or unaffordability) (reported 8 times) and the lack of specialists to repair and maintain the equipment (reported 7 times). The latter implies that the specialists working in the field assume that repairs and maintenance will have to be done by specialized mechanics and cannot be done by the farmers themselves. The equipment available at the village level is usually the cheapest and least durable. The enthusiastic farmer may persevere and improvise repairs, but as appropriate spare parts are seldom available, most will be discouraged and abandon further attempts to improve their pest control.
Respondents reported that cracks and leaks in containers and in overaged rubber hoses, and not renewing or loosing washers are a great cause for leakages that often poison the user, for waste of pesticides, for environmental pollution and for phyto-toxicity where pesticides fall on the crop in high doses. A major cause of poisoning when using a knapsack sprayer, is the spilling of pesticides over the back of the operator because of a faulty locking cap of the container.
Even when sprayers are working correctly, they will still need to be calibrated, especially in cases where the same nozzles are used for extensive periods of time. Although practised and taught in research and training institutes, the results show that calibration is hardly ever done in practice, resulting in incorrect dosage.
As the use of pesticides has negative impacts next to the positive effects, the question could be raised whether or not the current level of crop protection using chemical pesticides should be increased. Respondents generally have the opinion that the current level of crop protection in their country is too low; the lack of equipment and pesticides on the farm level was reported 15 times. Inconsistent pesticide availability is a major constraint to good pest control. Due to limited infrastructure and an inefficient supply chain, pesticides are not present when needed, thus defeating one of their most significant advantages, that of rapid effectiveness during sudden pest population increases. Another major problem is poor availability of application equipment and its appropriate maintenance. Obviously a breakdown of spraying equipment at the time when it is needed, which is mostly the time when farmers find out that the equipment is faulty, can lead to disaster in pest outbreak situations. These results from the field show that it is likely that farmers will increase the use of pesticides on their farms if they have the (financial) means to do so. Whether or not this is desirable remains an issue for discussion.
For some circumstances the equipment available is simply not appropriate. The problem that was reported most is that knapsack sprayers need considerable amounts of water per ha. For example, when a volume of 200 litres/ha is used, this requires some 10 headloads of 20 litres over distances of up to 1 km, which will involve over 6 man-hours effort. In other cases clean water may simply not be available and in many areas of the tropics, especially in the drier savannah areas, water remains the most crucial constraint to crop protection.
Farmers in the field are often unaware that pesticides should be used in a specific dosage in order to be as cost-effective as possible. Adding to this problem is the unavailability of measuring instruments, illiteracy of farmers and non-calibrated equipment. A means of assuring that at least the concentration of the pesticide in the spraying liquid is correct is the supply of pesticides in sachets containing sufficient for each knapsack load, as has been done in Central Africa. The system proved to be remarkably successful and durable for farmers who could obtain water (Gower and Matthews, 1971, as in Matthews, 1987). Still, this does not solve the problem of calibration.
Wrong dosage was reported nine times. In case of overdose farmers will incur financial losses because of waste of pesticides and phytotoxicity may decrease yields. The biggest risk however, of overdose and underdose, is the increased likelihood for the development of resistance against pesticides, which can have devastating large-scale effects on crop production. Not as much an example of the effects of under- or overdose specifically but more of the effects of general misuse of pesticides is the classic example of the development of resistance of the whitefly in cotton production in Sudan. Since the early 1960's endrin and dimethoate were introduced to control this insect. In spite of greatly increased pesticide use during the 1970's (less than one spray per year in 1960 to eight applications in 1980), cotton yields have continued to decline, mostly attributed to resistance of the whitefly to dimethoate. Now, a long-term program utilizing IPM concepts has been introduced using resistant varieties, biological control, improved agricultural practices, and more judicious use of pesticides. Unless the whitefly problem is solved, it could mean disaster for cotton production in Sudan and the crippling of their economy.
d. The environmental hazards that can result from pesticide use are only fairly recently known in the temperate world but far less is known about transport and fate of pesticides in the water and soil of desert and tropical areas. It is only poor comfort that most toxic and persistent pesticides that build op in the food chains are now banned. Pesticides have over the years become more specific and less toxic but environmental pollution still exists and since practically no data exist on this issue, the extend of the problem can only be guessed.
Environmental hazard as such was reported five times by the respondents. The kind of hazard was not specified further.
Fortunately it is generally believed that not only the present trend for a slowing down in the overall growth rate of chemical pesticide use will pursue but also that a combination of greater emphasis on integrated pest management (IPM) and biological control methods in general, and concerns about public health risks and ecosystem protection, will reduce both the rates of application and the environmental risks per unit of pesticide use (Alexandratos 1995).
It is clear that malpractice in pesticide application attributes greatly to the environmental hazard caused by pesticide use. Given the nature of pesticides, this hazard can never be eradicated but improving the situation, ranging from using better and properly functioning application equipment to training farmers, would minimize the damage.
All respondents pointed out that the problems they raised are very important and demand for an urgent solution. Although different respondents find different problems important, the answers point in direction of the final and main negative consequence of the shortcomings in today's crop protection practice: the decrease in yields and production. Environmental and health hazards were also mentioned but to a lesser extent. A conclusion of this could be that farmers generally lack the means to efficiently protect their crops against pests. Either they do not dispose of the machinery or pesticides to do it, or due to faulty equipment and lack of training and knowledge the treatment is done ineffectively, untimely and at high costs. To what extent this results in decreased yields is hard to quantify and varies from crop to crop and from zone to zone. Nevertheless some respondents point out that pests are the main cause of reduction in crop production.
In the regulation of pesticide application, government bodies have an explicit role to play. This is because of the fact that both producers and users are not likely to limit themselves in the sales and use of pesticides. Neither are they likely to be `self-regulating' in terms of minimizing health and environmental hazards, since this, in most cases, represents extra costs and no visible, short term profits. In relation to this issue an interesting response came from Senegal where a representative of a distributor of pesticides and equipment reported that the commercial sector in Senegal has committed itself to instruct farmers on the use of application equipment and on safety precautions. It would be a major step forward if not only distributors and retailers but also the producers would take on these responsibilities, even when this is contradictory to their natural desire to increase turnover.
Meantime this regulatory role of the government is generally not carried out satisfactorily. The effective control of pesticides in the West-African sub-region remains poor and seriously hampered by several factors including (Youdeowei, 1989):
a) lack of proper legislative authority;
b) shortage of trained personnel in pesticide regulatory procedures;
c) lack of infrastructure, transportation, equipment and materials;
d) very low budgetary allocation of operating funds;
e) lack of formulation control and pesticide residue analysis facilities and capabilities.
There are examples where these weaknesses in the abilities of the government-designated authorities to enforce approved regulatory procedures are fully exploited by producers of pesticides. Some of them export products to these countries in containers that are inadequately or wrongly labelled intentionally and in total disregard of the international guidelines approved for labelling and marketing pesticides. FAO has elaborated an International Code of Conduct on the Distribution and Use of Pesticides that should avoid these practices. The document sets forth and establishes voluntary standards of conduct for all public and private entities engaged in or affecting the distribution and use of pesticides. Although not yet legally binding, it is becoming increasingly mandatory. With the constraining factors, named in the last paragraph, governments and other institutions face difficulties to actually implement the code of conduct.
Although facing constraints in actually carrying out their activities, all responding countries except for Liberia and Sao Tom� and Principe have institutions in place that train farmers or extension workers on the use of pesticides, using the equipment, safety precautions etc. Normally it is the department of plant protection that carries out this task through the extension system of the ministry of agriculture. Additionally, a substantial number of farmers and extensionists is trained under projects such as the `Projet de Protection V�g�tale' in Burkina Faso or through parastatals such as the cotton societies.
In the ideal situation, governments should regulate and control the use of pesticides but leave the actual trade and importation of pesticides and equipment to the private sector. Unfortunately, in many countries, the Government is, through the Ministry of Agriculture, still the main importer of pesticides. As it is often the Crop Protection Service of the same Ministry of Agriculture that is regulating pesticide use, the implication is that the Ministry is regulating itself. This issue has been resolved in Ghana and Nigeria by the creation of bodies outside the Ministry of Agriculture. In Ghana this is the Environmental Protection Council and in Nigeria it is the Food and Drugs Administration and Control Department of the Ministry of Health (Youdeowei, 1989).
Quality control of pesticides is generally non-existent and farmers in developing countries can normally buy whatever is available on the global market. In practice this means that registration of pesticides is mostly based on the results of quality control and research carried out in the industrialised countries with temperate climates, which does not automatically qualify pesticides for use in the tropics. Additionally there are cases where countries allow or cannot prevent the use of pesticides that are generally banned elsewhere.
Concerning testing and controlling import and use of pesticide application equipment, Nigeria seems to be most advanced whereas it evaluates different types of equipment on a national level. Most countries reported no national control measures over the type and quality of equipment being used. This control is rather ad hoc and scattered over various institutions: In some countries, like Burkina Faso, specialised teams that visit farmers carry out pesticide control. These teams do carry equipment that has been tested and evaluated. In C�te D'Ivoire the `Centre Ivoirien de M�canisation Agricole' used to have a programme on pesticide application techniques but it collapsed because of budgetary constraints. Finally there are the cotton societies that carry out some testing and evaluation of equipment such as the `Compagnie Ivoirien de D�veloppement de Textile' in C�te D'Ivoire and `Sotoco' in Togo.
In general the regulations and control over the use of pesticides and the quality of the equipment leaves too many gaps. The result of this on the farm level is misuse and inappropriate use of pesticides with equipment that does not meet the minimum of quality standards. Next to health and environmental hazards this leads to waste of expensive pesticides, resistance of pests and decreased yields.
Existing problems: Low level of crop protection and bad state of equipment
The specialists in the field in the sub region, generally find the level of crop protection insufficient to effectively protect the crops against the number one constraint to increased production; pests. On the one hand they find that an increased availability and affordability of both sprayers and pesticides would improve the situation. On the other hand, it is the malpractice in pesticide application and the bad state of the equipment that hinders an effective application.
Specific equipment related problems that were mentioned are: firstly, leaks in containers and hoses and faulty locking caps that directly contaminate the user. Secondly, damaged or purposely enlarged nozzles that seriously hamper effective pest control and increase the use of costly pesticides. Thirdly there is calibration. In farming practice this is not done, resulting in incorrect dosage. Spinning disc sprayers may partly solve some of these problems because of being of a less complex technology, but risks of intoxication may increase.
Enhancing the knowledge that a farmer needs
The obvious solution for these problems is to create an environment that actively supports the end user with both `software', the knowledge that a user needs, and the `hardware', the physical inputs that a user needs. Concerning this knowledge, advising or training farmers on the basics of spraying could avoid most abuses. There is a strong call to strengthen extension systems, where needed, in their capacities to enlighten farmers on safety aspects, equipment issues, calibration, spraying techniques etc. All these efforts are not contradictory to the current trend of trying to reduce the use of pesticides, rather they are complementary to each other.
In cases where extension systems are not likely to be very efficient, small groups of specialized trainers could train the farmers. Another source of advice should be the retailers, be it co-operative societies or commercial retailers, as these are often the only source of information and farmers are inevitably in contact with them. It would show a good deal of goodwill from the side of the producing multinationals if they trained the retailers to be a reliable source of information for the farmer. Also the provision of protective clothing, gloves and masks with pesticides should be considered. Instructions on the label of pesticides could be improved but high illiteracy rates may prove this not to be effective.
Enhancing the equipment that a farmer needs
On the `hardware' side the private sector has a role to play. Due to `active' mismanagement of the equipment (damaging etc.) and the `passive' lack of maintenance, the majority of the equipment is in a bad state. Two of the main reasons are the lack of spares and the lack of trained mechanics for maintenance and repairs. From maintenance and sustainability problems with other technical farm inputs we have learned that an enabling environment for delivery of inputs and services is best created through enhancing the private sector. The set up of local outlets that also serve as service/repair centres deserves recommendation. Both farmers and these centres should benefit; farmers by cutting down on pest control costs by using properly adjusted and calibrated sprayers and the commercial sector earns by providing services and supplies. Also the cotton societies and other crop growers associations should be called in for co-operation since they have already proven to have the capacity to promote a more efficient and effective use of equipment and pesticides. On a national level a governmental body needs to promote and co-ordinate the commercialization of the supply chain. In combination with this enhancement of the supply chain, the set up of national or, preferably, regional testing and certification institutions could be considered. These institutions should operate within a legal framework and test, evaluate and certify sprayers before sale, preferably in combination with recurrent testing and certification of equipment in the field, after sales. In general, national governments should provide the basic conditions for a largely self-sustaining development of the agricultural equipment subsector within a policy of minimum direct intervention.
Safety
Next to the effectiveness of the application there is the safety aspect. Despite many efforts of governments to avoid acute and gradual poisonings, they still occur. Again, ignorance of farmers is one of the main causes. Unavailability and unaffordability of protective materials is another. Farmers may not be willing to invest in items that only protect their health but give no financial return. Farmers that are not fully aware of the hazards of pesticide contamination are not likely to make this investment. Government led improvement of the safety situation in pesticide application is still needed.
Reducing health and environmental hazards
Both producers and users are not likely to regulate themselves in the sale and use of pesticides, nor in minimizing health and environmental hazards. This is where government entities will have to play a regulatory role. The current level of regulation varies from country to country and queries in the questionnaire in this subject yielded answers ranging anywhere from no regulation whatsoever to full regulation. Thus it is dependent on the country to what extent this regulatory role needs to be strengthened. One aspect that calls for attention is the quality control of pesticides, which is non-existent in practically all countries. This means that registration of pesticides is based on registration in countries with temperate climate. Additionally, pesticides that are banned elsewhere are, in some cases, still used in developing countries. Promotion of the FAO code of conduct will attribute to strengthen the regulatory role of governments in this respect. Complementary to this code of conduct, the application and equipment issues, which are not covered by it, demand urgent attention, as discussed earlier.
Overall conclusion
The overall conclusion from specialists in the field is that farmers lack the means to efficiently protect their crops against pests. This problem overrules the problem of health and environmental hazards. The general urge to reduce pesticide use through systems like IPM and biological control needs to be encouraged but the use of pesticides is likely to show a moderate increase for some years to come and this aligns with the need for improved crop protection in a world with ever expanding needs for food. Thus next to the drive to reduce pesticide use we also need to face reality and promote the safe, effective and timely application of pesticides in those cases where it cannot be avoided.
References
Alexandratos (1995) World agriculture: Towards 2010, An FAO Study Food and Agriculture Organization of the United Nations. Rome
Cauquil J. (1985) Cotton pest control in sub-Saharan French-speaking Africa: Principle and review of techniques. Cot. Fib. Trop., 40, 195,202
FAO (1994) Pesticide application equipment for use in agriculture FAO Agricultural Services Bulletin nr. 112/1, FAO Rome
Friedrich, T. (1996) Agricultural Pesticide Application FAO Agricultural Engineering Branch AGSE, FAO Rome
Matthews, G.A. (1987) The integration of new technology in pesticide application systems for small-scale farmers in the tropics in: Marini Bettolo G.B. (ed.)(1987) Towards a second green revolution pp331-336.
United Nations (1991) Agro-Pesticides, Properties and functions in integrated crop protection Economic and Social Commission for Asia and the Pacific (ESCAP), United Nations, Bangkok
Youdeowei, A. (1989) Provisional report on pesticide management in Anglophone West Africa prepared for FAO Rome