23 February 2022
As more restrictions are placed on insecticide use for 2022, we look at the implications and how to minimise virus transmission by aphids
FURTHER restrictions on insecticide use and a rise in potato leaf roll virus (PLRV) over the past two seasons are reinforcing the need to accelerate adoption of integrated pest management (IPM) methods in 2022.
Over recent seasons, seed potato growers across Great Britain have been paddling against the current of insecticide resistance in aphid populations, insecticide product losses and, consequently, rising levels of non-persistent potyvirus like PVY.
Recent industry communications from Belchim and Syngenta, both of whom market products containing ISK’s active substance flonicamid, have advised growers not to use the insecticide in potatoes until further notice.
The issue relates to its maximum residue level (MRL) and manufacturers cannot guarantee there won’t be exceedances, even where the product is used in strict accordance with the product label.
There is already a label restriction which permits flonicamid being used with adjuvant oils, a practice which resulted in MRL exceedances in The Netherlands a few years ago.
It is understood that ISK IS working on raising the MRL in potatoes to solve the problem but acquiring the relevant data to submit to HSE-CRD will take time and there is no guarantee the situation will be sorted for the upcoming growing season.
Scottish Agronomy’s Eric Anderson says systemic insecticides like flonicamid are targeted at the main colonising aphids of Myzus persicae (peach potato aphid) and Macrosiphum euphorbiae (potato aphid).
In recent seasons, these species have started their flights early, arriving in potato crops soon after emergence with the threat of spreading virus.
To read our fuller feature, see the March issue of Potato Review. You can subscribe here.