The SPCS Aphid Monitoring Programme is suspended for 2013. SASA recommends that growers take advice from their agronomists over their virus management programmes for this season.
The levels of virus present in the 2012 seed crops, which provides the inoculum for virus infection in 2013, were relatively low. The incidence of crops containing leafroll fell to the lowest level on record in 2012 and the incidence of mosaics was the lowest since 2006. As the aphid vectors that transmit the viruses causing mosaics symptoms were very scarce last year, mosaics are expected to fall again in 2013. Although leafroll is expected to be a little more frequently observed this year, levels should not be much above those observed in 2012. Following a moderately cold winter, aphid vectors of leafroll are not expected to be numerous during the early season so the risk of further transmission is low. It is not possible to make long range forecasts of the abundance of the aphid vectors of mosaics. SASA therefore advises growers to consult the aphid monitoring pages where information on the abundance of aphid vectors based on the catches from a network of suction traps and