Myzus aphids on potato leaf - 4 July 2013

Aphids can infest potato leaves if left unchecked

Potato growers need to be alert to aphid infestations in their crops as warm dry weather continues, agronomists have warned.

The hot, dry weather has seen aphid numbers rise in potato crops, according to crop protection specialist Syngenta UK. Stephen Williams, the firm’s potato technical manager, said winged peach potato aphids were identified in a crop of Maris Pipers in south Lincolnshire on 4 July.

Williams said: “After the late planting and slow start to spring, many seed crops are still at early tuber initiation stage, when they are most susceptible to virus transmission by feeding activity of infected aphids.

'Seed crops must be protected as soon as possible. Growers with ware crop varieties susceptible to virus should adopt the same strategies.” Syngenta recommends the use of its Plenum product to control even resistant strains of aphids.

Peach potato aphid poses the most dangerous threat for transmitting potato viruses and presents one of the most difficult control challenges, but other aphid species can also spread infection and may even be present in far higher numbers that will affect yield. If winged aphids are seen on the crop, Williams said growers need to delve deep into the canopy and inspect a number of plants closely to see if the aphids are isolated pests that have flown in, or have developed from existing colonies in the crop.

Meanwhile, although aphid populations have been slower to develop in Scotland this season, seed potato growers are being advised to instigate aphicide programmes as quickly as possible.