Book of Abstracts
11th IFOAM Scientific Conference
11-15 August 1996, Copenhagen, Denmark
Danish Institute of Plant and Soils Science, Department of Plant Pathology and Pest Management, Lottenborgvej 2, DK-2800 Lyngby
Intercropped sorghum and pigeonpea are the primary crops of subsistence farmers in the semi-arid tropics of peninsular India. Helicoverpa armigera Hübner (Lepidoptera, Noctuidae) (HA) is the major pest, -highly polyphagous, fertile, and mobile. Insecticide resistance levels are high. Regional changes including increasing irrigation are suspected to contribute to increased HA damage.
Farmers' control methods of HA, and their knowledge of predators, were assessed in a case study in collaboration with a research/extension programme targeting duel purpose sorghum in the sorghum/pigeonpea intercropping system. It supplemented an experimental study of the potential role of predators in this cropping system.
Ten farmers having access to 1-3 ha of land were interviewed. Average fieldsizes were 0.2-0.4 ha. Sorghum and pigeonpea were grown for home consumption. All farmers indicated that intercropped sorghum/pigeonpea gave higher yields than either species grown as a sole crop. On sorghum, HA was a minor pest. In 1993 total yield losses in pigeonpea were 67% (range25-100%), similar results were experienced in 1992. Of these losses farmers attributed 30-40% to HA. Total crop failures were attributed to drought. Forty percent had sprayed against HA, none reported any insect control. Farmers were not familiar with any other control measure.
HA and its arthropod predators were sampled in the participants fields with the farmers present. Only one farmer recognised HA eggs, others recognised larger larvae. Most had seen the larger predators before, but did not know that they were beneficials. The smaller predators were not recognised.
This study showed that farmers' knowledge focused on the cropping system per se rather than separate elements, as pests and beneficials. They recognised obvious advantages in the system, but changes to improve natural control of HA on pigeonpea are needed in this system. This conclusion is supported by experimental results. Poor, illiterate farmers do not have the resources to develop such alternatives.
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