Assessing yield impacts of bean leaf roll virus and pea enation mosaic virus in lentils inoculated at different growth stages by pea aphid (Acyrthosiphon pisum)

Pea enation mosaic virus  (PEMV) and Bean leaf roll virus (BLRV) are the most serious viral diseases affecting cool season food legumes in the Pacific Northwest.  In this region, these two viruses are almost exclusively transmitted by the pea aphid (Acyrthosiphon pisum). There are few studies to quantify the injury caused by pea aphids in lentils due to their direct feeding, and none that incorporate the effects of virus transmission. Management decisions are traditionally based on the rules of thumb, which are imprecise and only account for the direct feeding damage, but not the disease damage.

A field study was carried out at the University of Idaho to assess the injury resulting from inoculation of lentil plants with PEMV and BLRV at different growth stages. Plants were inoculated with the viruses using aphids at different times after emergence and the effects were assessed in terms of yield at harvest. Yield loss was greatest for plants inoculated at 10 days after emergence and declined thereafter. The relationship can be used in conjunction with virus prevalence data to guide producers in making decisions about the timing of aphid control measures.