Distribution and transmission of Sugarcane Yellow Leaf Virus (SCYLV) in Hawaii and its elimination from seedcane

Abstract

Sugarcane yellow leaf syndrome (YLS) was first recorded in the late 1980s on the island of Hawaii. One form of YLS is caused by the sugarcane yellow leaf virus (SCYLV). A survey of the distribution of SCYLV revealed that all plants of some cultivars contained the virus, often when there was no symptomatic leaf yellowing. However, some cultivars were always virus-free and were classified as resistant to SCYLV. Possible alternative hosts, such as grass weeds and cereals, were always virus-free. Surprisingly, so were plants of susceptible cultivars that had survived as volunteer plants in former plantation fields that had not been cultivated for 20-30 years. Virus-free plants were produced with high efficiency from susceptible cultivars by meristem tip culture. Reinfection of virus-free plants when fed upon by viruliferous Melanaphis sacchari proved that SCYLV is transmitted by this aphid. Three weeks after viruliferous aphids were removed from the leaves of the test plants, virus particles were detected in the shoot and tiller meristems and root tips. After three months, all parts of inoculated plants were infected. The rate of spread of SCYLV from plant to plant, both down and across rows, was slow, in the range of 2-5 m per year. f