A network that helps people worldwide obtain rapid advice and information on crop protection, including the identification and management of plant pests.
PestNet is a network that helps people worldwide obtain rapid advice and information on crop protection, including the identification and management of plant pests. It started in 1999. Anyone with an interest in plant protection is welcome to join. PestNet is free and is moderated, ensuring that messages are confined to plant protection.
Disease-like symptoms were reported from a small field of Colocasia taro on Tutuila, the main island of American Samoa. Leaves showed severe chlorosis and yellowing that appeared to radiate outward from the petiole and from each vein. The condition is scattered throughout the field and affects all leaf ages. There was no information on recent chemical application, either on-farm or nearby.
Several suggestions were made, but the concensus was that the problem was due to Dasheen mosaic potyvius, DsMV.
1. Mites – suggested but rejected 2. From Hawaii – some Samoan taros were said to be very susceptible to Dasheen mosaic potyvirus. The commercial Hawaiian taros are very tolerant. Unfortunately, they are susceptible to Phytophthora leaf blight. Some of the hybrids created by Cho and Trujillo have good resistance to Phytophthora leaf blight and are tolerant to Dasheen mosaic potyvirus infections. 3. From Samoa – the yellowing of leaf is similar to cv. Palau – 7, but plants looks normal and healthy. 4. From Queensland University of Technology – QUT is currently characterising the viruses infecting taro and developing diagnostics. As part of this, a taro virus survey is being organised throughout the Pacific Islands and it would be useful to collect taro with these symptoms. 5. From past experiences, plants free from DsMV grown from tissue culture often show severe symptoms of the DsMV when first re-infected.