Controlling sugarcane diseases in Florida: a challenge in constant evolution

Diseases are limiting factors for the sugarcane crop in almost any sugarcane growing location. More than 40 diseases have been recorded in Florida, with brown rust, orange rust and yellow leaf currently impacting on sugarcane production. Ideally, these diseases should be controlled using resistant cultivars, but most cultivars grown in 2015-2016 in Florida are susceptible to either brown rust or orange rust. Several cultivars that were initially resistant to orange rust became susceptible when grown over large areas, suggesting a change in the rust pathogen populations. At the present time, control of the two rust diseases relies mainly on use of fungicides. Most cultivars are also susceptible to infection by Sugarcane yellow leaf virus (SCYLV) and it has been shown that this virus can reduce yields even in absence of disease symptoms. Use of healthy seed cane is only partially successful and the recently discovered new host and potential vector of SCYLV may explain the difficulty in controlling this virus in Florida. Identification of sustainable resistance sources and transfer of these resistances to new cultivars are critical for successful control of sugarcane diseases in Florida. (Résumé d'auteur