Pathogenic fungal diseases of perennial trees require innovative management strategies. Curative treatments, effective at all points of the disease cycle, are crucial to protect perennials with long generation times. Myrtle rust (caused by Austropuccinia psidii) impacts more than 400 species across 70 genera of perennial trees and continues to spread throughout the Southern Hemisphere. Its invasion in Australia is rapidly leading to the imminent extinction of 16 endemic rainforest species in a single generation, with at least 20 more at high-risk. Our previous study demonstrated that double-stranded RNA (dsRNA) significantly inhibited the infection physiology of A. psidii and reduced disease symptoms on plants. We have since shown that dsRNA can be applied to plants exogenously pre- and post-infection to prevent and cure myrtle rust at different stages of infection. Plants treated with dsRNA exhibited decreased disease coverage and increased growth and photosynthetic capacity. Curative dsRNA provides a new tool in the management of the catastrophic, decade-long epidemic of myrtle rust in Australia. Beyond control measures, dsRNA-based assays provide new possibilities in the study of rust fungi and obligate fungal pathogens, where gene-editing techniques are not feasible. Our current work utilises dsRNA to investigate the evolution of effectors in polyphagous rust fungi. Through cloning and colony PCR screening of a predicted effector, we have identified a family of candidate effector genes that have proliferated in the genome of A. psidii. Our recent findings suggest that dsRNA-mediated knockdown of closely related genes in this family produce differential, target-dependent effects on spore germination.