Aphid management to minimise the spread of non-persistent viruses in potato seed crops

Potyviruses, principally strains of PVY, have become increasingly prevalent in ware crops, leading to concerns over the health status of seed tuber supply chains. Methods for reducing spread in seed crops are limited, due to loss of insecticides, resistance to remaining products, and the difficulty of controlling non-persistent virus transmission with insecticides. Generally milder winters are also increasing vector pressure early in the season. Mineral oils are known to be effective in reducing virus incidence, but effects have been inconsistent. Recently, work in Europe and Canada showed that frequency and timing of sprays is critical, and that certain cultural techniques (straw mulches and intercropping) can provide additional benefits. Some of these approaches are being trialled under GB conditions.

2020

The trial was located at Cambridge and compared eight aphid managment programmes. The treatments were applied from 30% emergence at weekly intervals and consisted of combinations of untreated, a full insecticide programme, mineral oils, an adjuvant spray oil, straw mulch and a vetch inter-row crop. Plots were harvested and graded, and tubers taken from each plant for virus testing by ELISA. There was no statistical evidence that a full programme of insecticides alone reduced the very high levels of virus seen in untreated plots (100% for PVY^O/C and 85.4% for PVY^N). However, all of the oil products, oils plus insecticide, and oil with either straw mulch or vetch, reduced the incidence of PVY^N in harvested tubers compared to untreated plots. The trial was repeated in Scotland in 2021 and the final report will be published in spring 2022. 

The project aims to understand newer approaches for the management of aphids in potato crops, and how these contribute to minimising the spread of potyviruses in seed tubers