Fig Rust

Fig rust, caused by Cerotelium fici, is an obligate fungal pathogen that completes its life cycle entirely on fig tissue. Unlike many rust fungi, it does not require an alternate host, which means infections can cycle repeatedly through the same planting as long as living leaf tissue and sufficient moisture are present.

The disease favors warm, humid conditions typical of southeastern summers, particularly when nighttime temperatures stay above 60°F and leaf surfaces remain wet for extended periods. Spores released from the reddish-brown pustules on leaf undersides spread by wind and splashing water, allowing rapid progression through a planting once established. The visible damage, yellow lesions on the upper leaf surface followed by premature defoliation, rarely kills established trees outright, but repeated late-season leaf drop can reduce the carbohydrate reserves that support the following year's fruit crop.

Management is most cost-effective when it starts with site selection and sanitation rather than fungicide applications. Figs sited in full sun with good airflow dry faster after rain, which meaningfully reduces infection periods. Collecting and removing fallen leaves in autumn interrupts the local inoculum cycle. Where trees are planted in marginal sites or disease pressure has been severe in prior years, copper-based fungicides applied at early signs of infection can slow spread, though they do not eliminate established lesions. No varieties are listed in the current dataset as having confirmed resistance to Cerotelium fici; variety selection guidance may be updated as regional trial data becomes available.