A BYDV alert tool developed over the past four seasons by Agrii’s decision support team is proving invaluable in helping agronomists and their growers across the country maintain the most effective winter cereal aphid control in the face of increasingly variable national and local weather.
The tool – in the form of an app for agronomists’ smart phones, tablets or laptops – employs the company’s national network of physical and virtual weather stations to provide daily in-season tracking of local aphid risks using the established T-Sum method. It is also proving useful ahead of the season in assessing local risks for both treated and untreated seed at any sowing date based on the warmest and coolest seasons of the past 30 years.
“Our BYDV Alert App gives an immediate graphic representation of the accumulation of day degrees over 3oC for any site each day through the key aphid risk period for autumn-sown crops,” explained developer, Dr Francesca Salinari.
“We know it takes an average of 170 of such day degrees for the second generation of wingless aphids to be produced, leading to the rapid spread of BYDV. After a further 170 degrees the third generation will appear, at which stage their progression and BYDV spread becomes exponential.
“We also know the benchmark temperature requirements for wheat emergence and the length of effective protection given by both seed treatments and pyrethroid sprays.
“By bringing this intelligence together with automatically up-dated daily temperature records from our weather stations we can provide accurate estimates of aphid risk and spraying alerts for first and follow-up insecticide foliar applications at any site in the country.
“Our decision support app gives agronomists an up-to-date map of the UK colour-coded for aphid risk in 25km squares, together with the ability to assess the current risk for any of their crops by individual location and sowing or last spray date at the touch of a button,” she pointed out.
Agrii’s BYDV Alert App records for the past few years underline the extent to which aphid risk has varied with sowing date, seed treatment and season as well as location, making spraying decision-making increasingly difficult.
