Resumo

HOLGUIN A, CLAUDIA MARÍA  e  BELLOTTI, ANTHONY C. Effect of chemical insecticide application for control of the whitefly Aleurotrachelus socialis (Homoptera: Aleyrodidae) in cassava Manihot esculenta Crantz. Rev. Colomb. Entomol. [online]. 2004, vol.30, n.1, pp.37-42. ISSN 0120-0488.

In recent years the whitefly Aleurotrachelus socialis Bondar has been the most important pest affecting the cassava crop in Colombia. In order to search for different alternativos in an integrated management program, three experiments were conducted under field conditions in Jamundi (Valle del Cauca) in a complete randomized block design, with the cassava variety Reina. In the first trial the foliar application of different insecticides was evaluated. The treatments corresponded to imidacloprid 1, buprofezin, carbosulfan, tiametoxan, diafentiuron, piriproxifen and imidacloprid 2. In the other two experiments we sought to delay appearance of the pest by evaluating different doses, forms an application periods of imidacloprid: drench of the seed at planting and emergence of the first leaf, and stake immersion, reinforced with foliar applications. In all experiments egg, nymph and adult populations were evaluated based on a population scale ofl to 6. The foliar application with tiametoxan, imidacloprid 1 and 2 presented the lowest population valúes for adults, eggs and nymphs compared to the control. When imidacloprid was used at planting and immersion or seed drenching, the crop was protected between 45 and 60 days. At the economic level, for farmers with large planting áreas the benefits are greatest by using only foliar applications. For small-scale farmers chemical control is only beneficial with one product in foliar form. When used from planting on, the small-scale farmer gained no benefits from any of the treatments.

Palavras-chave : Chemical insecticides; Frogskin; Cost - benefit rallo.