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Antibiosis and antixenosis to Aphis gossypii (Homoptera: Aphididae) in Colocasia esculenta

Coleson, J.L., Miller, R.H.
Journal of economic entomology 2005 v.98 no.3 pp. 996
Aphis gossypii, Colocasia esculenta, taro, Xanthosoma sagittifolium, pest resistance, antibiosis, antixenosis, cultivars, varietal resistance, germplasm screening, population density, mortality, fecundity, longevity, Guam
Fifty cultivars of taro, Colocasia esculenta (L.) Schott (Araceae), collected from islands in Micronesia and Polynesia, eight cultivars from the University of Hawaii's taro germplasm collection, and a closely related aroid, Xanthosoma sagittifolium (L.) (Araceae), were screened for antibiosis and antixenosis to Aphis gossypii Glover. Life history data for A. gossypii were collected by assessing survivorship and fecundity of aphids caged on taro leaves in the field. Significant differences in aphid reproductive rate and longevity were observed among the taro cultivars, and cultivars were ranked from most resistant to most susceptible. Antixenosis was assayed in the laboratory in a multiround choice test where A. gossypii were offered four leaf discs excised from different taro cultivars. Additionally, field observations of aphid abundance on taro cultivars were made to corroborate clip cage studies and laboratory experiments. 'Iliuaua', 'Rumung Mary', 'Maria', 'Ketan 36', and 'Agaga' were the most resistant in terms of reducing aphid fecundity and survivorship, whereas the Iliuana, 'Purple', 'TC-83001', and 'Putih 24' were least preferred in aphid choice tests. X. sagittifolium consistently exhibited strong aphid resistance. Resistant cultivars identified in this study may form the basis of breeding programs seeking to combine aphid resistance with other desirable agronomic traits in taro.