Preliminary attempts to identify pathogens as biological control agents against Cestrum species (Solanaceae) in South Africa

In 2008, a field survey was conducted in northern Argentina to collect natural enemies of Cestrum species (Solanaceae) for use as biological control agents in South Africa. The rust fungus Uromyces cestri Bertero ex Mont. (Pucciniales: Pucciniaceae) was found on Cestrum parqui L'Her. and imported into quarantine facilities in South Africa. No damaging pathogens were found on Cestrum laevigatum Schltdl. Preliminary host-range studies showed that U. cestri was able to infect and cause disease on C. parqui and on Cestrum elegans (Brongn. ex Neumann) Schltdl. in South Africa, and could have potential for the biological control of these species. The rust did not infect any of the other Cestrum species tested, and neither did it infect C. laevigatum which is the most problematic Cestrum species in South Africa.