Identification of potential hosts plants of Cowpea aphid‐borne mosaic virus

Among the major pathogens affecting passion fruit orchards, the cowpea aphid‐borne mosaic virus (CABMV), also known as the fruit‐hardening virus, has gained prominence owing to its role in the drastic reduction in fruit production in yellow passion fruit orchards ( Passiflora edulis f. flavicarpa) from the second year of cultivation. To mitigate the damage, several regions adopt the annual planting system where a sanitary void is maintained from August to September. However, the virus is believed to remain dormant in weeds. This study aimed to identify potential weed hosts of CABMV. The study was conducted with a randomized design with four replications in Londrina, PR. Twenty‐eight weed species were tested, and a sample of yellow passion fruit leaves symptomatic for CABMV infection was used as the virus inoculum source. Mechanical inoculation was performed using the extract from the symptomatic plant. Symptoms were visually evaluated every 3 days. For molecular confirmation, total RNA was extracted, followed by RT‐PCR with CABMV‐specific oligonucleotides, reinoculation in passion fruit plants and sequencing. CABMV infection was observed in southern sandbur ( Cenchrus echinatus ), Siberian motherwort ( Leonurus sibiricus ), showy rattlepod ( Crotalaria spectabilis ) and yellow passion fruit ( Passiflora edulis ). The CABMV‐positive weed species extract was able to infect yellow passion fruit plant when a fresh mechanical inoculation was performed. Showy rattlepod ( Crotalaria spectabilis ) was the only weed species to exhibit observable symptoms of CABMV. C. echinatus , L. sibiricus and C. spectabilis act as a source of CABMV inoculum.