Unusually mild symptoms of potato leafroll virus in the progeny of late-infected mother plants

Summary In a field experiment in which the date of potato leafroll virus (PLRV) inoculation was controlled, progeny plants derived from late infection of mother plants in the previous year showed much milder symptoms than progeny plants derived from mother plants that became infected earlier in the season. Plants with these milder symptoms contained as great a concentration of PLRV as progeny plants with more obvious symptoms derived from early primary infections.