ABSTRACT Recent reports of tomato severe rugose virus (ToSRV, Begomovirus solanumseverugosi ) infecting common bean ( Phaseolus vulgaris ) and soybean ( Glycine max ) in Brazil, together with the observation of high ToSRV incidence in tomato crops adjacent to ToSRV‐infected soybean fields, reinforce the hypothesis of the occurrence and epidemiological relevance of ‘amplifier hosts’. One objective of this work was to characterise the conditions under which this phenomenon occurs. The results revealed that plants of all tested soybean and bean cultivars were susceptible to infection by different ToSRV isolates. Furthermore, soybean plants at vegetative stages were more susceptible to ToSRV infection than those at reproductive stages; a similar pattern was also observed in bean plants. When ToSRV‐infected soybean and bean plants reached later reproductive stages, they acted as important sources of ToSRV inoculum for tomato plants. Another objective of this work was to provide experimental evidence of the amplifier host concept under field conditions. After removing an initially ToSRV‐infected tomato crop, high levels of asymptomatic ToSRV infection (62%–94%) were detected in adjacent soybean plants, which subsequently served as the inoculum sources for a second tomato planting. In this subsequent tomato crop, disease incidences reached up to 95%–100%. The ability of soybean plants to sustain asymptomatic ToSRV infections while supporting Bemisia tabaci populations positions soybean as a key epidemiological bridge between infected tomato plants and new tomato crops, providing a strong but short‐term infection pressure that initiates new ToSRV epidemics.
Bello et al. (Fri,) studied this question.