|Survey of virus diseases of taro, Colocasia esculenta, in American Samoa|
N. ATIBALENTJA (1), E. M. Ilaoa (1), S. T. Fiafia (1), I. B. Gurr (1). (1) American Samoa Community College, Division of Community and Natural Resources, Pago Pago, U.S.A.
Taro, <i>Colocasia esculenta</i>, is the most important staple crop in the U.S. territory of American Samoa, where it also serves in many cultural functions. In this South Pacific archipelago, taro diseases caused by viruses come second only to taro leaf blight (<i>Phytophthora colocasiae</i>), which devastated taro production in the early 1990s. This study investigated the incidence of taro-infecting viruses in the two major taro growing islands of American Samoa: Tutuila and Aunu’u. Leaf samples were collected from each of 164 symptomatic taro plants in both islands. Total genomic DNA and RNA were extracted from each sample, and the extracts were assayed by PCR and RT-PCR for each of five viruses known to infect taro worldwide. Dasheen Mosaic Virus (DsMV) and Taro Bacilliform Virus (TaBV) were the most prevalent viruses, infecting 80% and 6%, respectively, of 96 plants examined in Tutuila, compared to 76% and 28%, respectively, of 68 plants in Aunu’u. Many of the plants that tested positive for DsMV also were co-infected with TaBV. Cultivar ‘Palau 10’ was particularly susceptible to DsMV in Tutuila, with 100% of 22 plants testing positive. In Aunu’u, ‘Talo Manua’ was the most susceptible to both DsMV and TaBV, with 100% and 38% of 13 plants, respectively, testing positive. This is the first report on the incidence of taro diseases caused by viruses in the Aunu’u Island.