Pea aphid (Acyrthosiphon pisum) outbreak cycles in the US Pacific Northwest

The pea aphid adversely affects the health and vigor of field peas in the U.S. Pacific Northwest by sucking sap from plants and transmitting viruses. When massive pea aphid flights arrive in this region without warning, pea producers are caught off guard and cannot implement timely control measures. This talk documents pea aphid outbreak cycles over a 26-year period in eastern Washington where 1983, 1990, 1996, and 2005 were 'outbreak years'. While the database does not demonstrate a consistent link between mild winters and aphid outbreaks, it reveals a periodicity with outbreaks occurring every 5-9 years in this region. This study represents a new long-term data set that will improve understanding of how different abiotic and biotic factors influence the life-history processes of a pest aphid.