TWENTY FIVE YEARS OF PRESENCE OF THE COTTON BOLL WEEVIL IN THE SOUTH CONE

The cotton boll weevil, Anthonomus grandis Boheman, was first detected in Brazil in February of 1983. From there, it moved to neighboring Paraguay in 1991 and subsequently to Argentina in 1993. Today, it is present in the most important cotton producing areas of the region. This insect pest has caused much economic and social damage in the South Cone of South America, repeating the havoc it had previously brought to cotton producing countries in more northern latitudes. At its arrival to Brazil, an eradication program was proposed but never implemented for political and environmental reasons. The boll weevil changed Brazilian cotton geography and the way cotton was grown, from the traditional subsistence crop-sharing system in the Northeast and small holder agriculture system in the mid- South, to present fully mechanized large farming systems of the mid-West, previously not yet infested by the pest. In Paraguay, where cotton was vital to an essentially agricultural economy, the pest has brought an overall area reduction of 80%. In Argentina, it was contained for many years from the great Chaco producing area, now also infested. Control actions are carried out by farmers individually and are a combination of cultural and chemical control methods. Since the arrival of the boll weevil to the region, an increase in pest control costs due to recurrent insecticide sprayings has made cotton production less competitive in the world market. The presence of the boll weevil in the South Cone nullifies any potential benefit of the recently introduced bollworm resistant GM cultivars. Area wide suppression efforts have been initiated in some Brazilian states. With the eradication in the US, countries to the South will have to strengthen their research efforts if they are to continue to produce cotton in the presence of the boll weevil. The author analyses the cotton production in the South Cone since the arrival of the boll weevil.