If you have not yet started trapping please note that traps should go out 2 weeks before emergence.
If you have started trapping please ensure that you have sent us a grid reference.
23 samples have been received so far this year.
Peach-potato aphids and potato aphids have been found in samples from the Midlands, East Anglia and the South West during the last week. We have also found peach-potato aphids in samples from other crops in the Northern England.
Black-bean aphids were found in samples from the Midlands and East Anglia. Twice as many black-bean aphids were found compared with the average for all previous years in samples from the Midlands.
North of Scotland: No samples
Grampian: No samples
Angus and Perthshire: No samples
Borders: No samples
Northern England: No samples
Midlands: Virus pressure was high. Peach-potato aphids were found at 2 sites (27 at one site). Potato aphids were found at 2 sites. Other potato virus vectors found: black-bean aphid (a good vector of PVA), cabbage aphid, grain aphid, leaf-curling plum aphid, pea aphid, willow-carrot aphid. Twice as many black-bean aphids were found compared with the average for all previous years.
East Anglia: Virus pressure was low. Peach-potato aphids were found at 3 sites. Potato aphids were found at 1 site. Other potato virus vectors found: black-bean aphid (a good vector of PVA), bird-cherry oat aphid, currant-sowthistle aphid, grain aphid, leaf-curling plum aphid, willow-carrot aphid.
South West: Virus pressure was moderate. The virus pressure was five times higher than the average for all previous years. Peach-potato aphids were found at 1 site. Twice as many peach-potato aphids were found as the average for previous years. Potato aphids were found at 1 site. Other potato virus vectors found: bird-cherry oat aphid, cabbage aphid, currant-sowthistle aphid, leaf-curling plum aphid, rose-grain aphid, willow-carrot aphid. Three times as many currant-sowthistle aphids were found as the average for all previous years.
The black-bean aphid (Aphis fabae) has been found to transmit PVA so if you are growing PVA susceptible varieties (Desiree, King Edward, Maris Peer, Marfona etc) you may wish to take this into account.
Cereal aphids: Grain aphids have been found in samples from the Midlands and East Anglia in the last week; Rose-grain aphids have been found in samples from the South-West in the last week.
Along with the results from your aphid trap you need to take into account the following
factors when considering the risk of virus spread.
Mature plant resistance. Crops are generally at their most vulnerable
within the first four weeks from emergence. After this time 'Mature Plant Resistance'
builds up which makes it more difficult to transmit virus within the crop. The crop is
again more vulnerable to virus spread if there is regrowth after dessication.
Cultivar resistance. Different varieties of seed will have different
inherent natural resistance to PVY. Using a more resistant cultivar will reduce the
risk of virus transmission.
Volunteers and seed quality. In most situations it is unlikely that
aphids will bring PVY into your crop (see next note). The greatest risk is from aphids
spreading what little virus may already be present. This can come from two possible
sources. Volunteers from previous potato crops and low levels of virus in the seed
Surrounding crops. The risk of aphids spreading PVY to your crop
from elsewhere is increased when ware crops are grown close to your seed. This is
because there will be greater numbers of aphids and ware crops generally have a
higher incidence of virus present.