Pesticides used on cotton

Cotton is the major market for insecticides and consumes almost 25% of all use each year, for example 23.9% of the US$7,400 million market in 1992(1) . Substantial volumes of herbicides are used to defoliate the cotton to allow mechanical harvesting. A study of pesticide use in cotton in the 1988 crop year(2) indicated that the main active ingredients used were the synthetic pyrethroids cypermethrin, deltamethrin and fenvalerate/esfenvalerate;  the organophosphates (OPs) monocrotophos and parathion/parathion methyl;  the carbamate aldicarb; and the organochlorine endosulfan. Apart from the synthetic pyrethroids, all these active ingredients have been reported to cause health or environmental hazards in developing countries(3). OPs are particularly hazardous to workers health, but are cheaper and are thus used more widely in developing countries.  Insect resistance to pesticides is a major problem and while IPM techniques could successfully reduce pesticide use and minimise insect resistance, they are not widely practised, rather there is rotation of different classes of pesticides, especially OPs and pyrethroids.  Industry expects all  principle insecticide categories, except organochlorines, to rise in the coming years, and OPs will be by far the largest individual category, almost twice as much as carbamates, and pyrethroid sales will slow.

Hazard warnings 
WHO hazard classification is in brackets the first time a pesticide appears. This indicates the acute risk to health of exposure (mainly oral or dermal) over a relatively short period of time and refers to the technical compound. Formulations and spray strength may be weaker. FAO recommends that WHO Ia and Ib should not be used in developing countries. Organophosphates appear in italics.
    The WHO classifications are:  Ia extremely hazardous;  Ib highly hazardous;  II moderately hazardous;  III slightly hazardous;  5 unlikely to present acute hazard in normal use.

Use in selected countries

US:(4) 1994 sales of insecticides on cotton US$418.5 million. Leading products were acephate (III), aldicarb (Ia), lambdacyhalothrin (II).

Greece:(5) Greece and Spain are the only two cotton growing countries in the European Union and Greece is by far the larger. Main pesticides used were reported as cyanazine (II), ethalfluralin (5), glyphosate (5) and pendimethalin (III).

Africa:(6)  Cotton is the largest market for pesticides in Sub-Saharan Africa. Major products are cypermethrin (II), dimethoate (II) and profenofos (II). West African production is dominated by French interests and benefits from French research:  spraying is generally limited to a maximum of 7 times in the 4-6 month season.

Egypt:(7)  Pesticides used include dimethoate, malathion (III), methamidophos (Ib), methomyl (Ib).

Benin:(8) Main pesticides used are chlorpyriphos (II), cypermethrin, dimethoate, lambdacyhalothrin, profenofos and triazophos (Ib).

Senegal:(9) The main pesticides used are cypermethrin/alphacypermethrin, deltamethrin (II), dimethoate, monocrotophos (Ib) and methamidophos. Of the US$2,200 million spent on pesticides in 1992, the majority was for use on cotton.

Sudan:(10) Pesticides registered for use on cotton in Sudan have been (some of these may be superseded): aldicarb, carbaryl (II), chlordane (II), demeton-S-methyl (Ib), dicrotophos (Ib), endosulfan (II), heptachlor (II), leptophos (Ia), malathion, monocrotophos, phosphamidon (Ia), thiometon (Ib), tri-allate (III), toxaphene (II). A total of US$30-40 million is spent on pesticides each year, mainly on cotton.

India:(11) Recommended insecticides include aldicarb, carbaryl, carbofuran (Ib), chlorpyriphos, cypermethrin, decamethrin, demeton-S-methyl, dicofol (III), dimethoate, endosulfan, fenvalerate (II), monocrotophos, phosalone (II), phosphamidon, quinalphos.  (Aldicarb and carbaryl were made at the Bhopal plant by Union Carbide for use on cotton.) Sales increased in 1994.

Brazil:(12)  Pesticides used include carbofuran, demeton-s-methyl, dicofol, disulfoton, endosulfan, monocrotophos, paraquat (II), parathion methyl (Ia).

Nicaragua:(13) Approximately 80% of pesticides imported are for cotton production and include acephate, alphamethrin, bifenthrin (II), Bt, chlorpyrifos, cyhalothrin (II), cypermethrin, deltamethrin, dicrotophos, malathion, mephosfolan (Ia), methamidophos, methomyl, methyl parathion, paraquat, profenofos, terbufos (Ia), thiodicarb (II); also toxaphene which is now made in Nicaragua.

Paraguay:(14)  A great many pesticides are available on the market, many of which are smuggled into the country. The most commonly used on cotton are fenvalerate and monocrotophos. (BD)

References
1.  Francois Colliot and L le Roux de Bretagne, of Rhône Poulenc, reported in Agrow No. 199, 7 January 1994, p.17.  
2.  Rosier, M.J., of MTM Agrochemicals, 'Cotton Crop Profile', Pesticide Outlook, 1:5, November 1990, p. 19. 
3.  Dinham, B., et. al., The Pesticide Hazard: A global health and environmental audit, The Pesticides Trust [now PAN UK], 1993. 
4.  Mike Buckley and Associates, 1994 Cotton Insecticide Study, San Francisco, US, 1995. 
5.  Greek Cotton Association, pers. comm. to Anne Davidson of the Consumers Association, 25 May 1995.  
6.  Agrow No. 213, 5 August 1994. p. 21. 
7.  Dinham, op. cit.  
8. Ton and Vodouhe, see page 14.  
9.  Senegal case study, The Pesticides Trust [now PAN UK], 1993.  
10. Sudan case study, PT, 1993. 
11.  ICAR (Indian Council of Agricultural Research), India, 1991.  
12.  Dinham, op. cit.  
13.  Nicaragua case study, PT 1994.  
14.  Paraguay case study, PT 1993.

[This article first appeared in Pesticides News No. 28, June 1995, page 23]