YIELD EFFECT AND VECTOR CAPACITY OF PEA APHID IN TRANSMITTING PEA SEEDBORNE MOSAIC VIRUS ON CHICKPEA AND FABA BEAN

Pea seed-borne mosaic virus (PSbMV) is an important potyvirus affecting pulse crops, yet its impact on chickpea and faba bean in Western Canada remains poorly characterized. This study examined PSbMV symptom expression, yield effects, and aphid-mediated transmission in chickpea (CDC Orkney) and faba bean (CDC 1310-05) and pea (CDC Meadow) under controlled conditions. Plants were mechanically inoculated with the L09 PSbMV isolate, and infection was verified using RT-PCR and qPCR. Symptom development, plant growth, pod formation, seed characteristics, and infection status were recorded. Additional assays assessed transmission efficiency using viruliferous pea aphids (Acyrthosiphon pisum) at different densities. Chickpea showed high susceptibility to PSbMV. Infected plants exhibited pronounced mosaic, tip necrosis, severe stunting, and complete failure to produce pods. Plant height was reduced by approximately half relative to healthy controls, and viral accumulation was consistently detected. In contrast, faba bean expressed milder foliar symptoms, maintained normal height and pod set, but produced seeds with mottling, wrinkling, and discoloration. Seed counts in faba bean showed a downward trend, though not statistically significant. Pea developed characteristic PSbMV foliar symptoms, including mosaic, chlorosis, leaf curling and stunting, consistent with typical potyvirus infection. Aphid transmission exhibited a clear dose-dependent pattern, with infection occurring even at low aphid densities in faba bean. Overall, the results indicate that early PSbMV infection can cause complete yield loss in chickpea, while faba bean, although more tolerant, can sustain infection and contribute to virus persistence. These findings highlight the importance of clean seed, early detection, and vector management in reducing PSbMV risk in pulse production systems in Western Canada.