Data from a 2025 trial has been published by Richard Austin Agriculture that demonstrates how using biostimulants has reduced the impact of late potato blight and increased yield. The results show positive outcomes which may help to offset the recent upsetting news that a first confirmed case of the dangerous EU_43 blight in the UK has been established.

“Blight control is becoming increasingly challenging as new strains continue to emerge and resistance to some fungicides continues to develop. This trial looked at how biostimulants such as Sirius and Trident Plus could be used alongside a conventional fungicide programme to support crop performance. The results were encouraging in terms of yield and crop response, but further field-scale trials will be needed to better understand their role within an integrated approach to late blight management,” says Richard Austin Agriculture trials manager, Michael Rodger.

The plot trial used the Melody variety and applied the biostimulants from July to October, along with fungicides Enervin and Privest. The best total yield was achieved with a mixture of Sirius and Trident Plus, which also had a comparable percentage of blight infection to using just Privest and a lower percentage than the combination of Phusion and Enervin.

“Biostimulants may help reduce the impact of late blight indirectly by improving plant resilience rather than directly controlling the pathogen. Silicon can strengthen plant cell walls and create physical barriers that make infection more difficult. It can stimulate natural plant defence responses so the crop reacts more quickly to infection,” adds Mr Rodger.

He further suggests that biostimulants can improve overall plant vigour, nutrient uptake and stress tolerance, helping plants maintain growth and yield even under disease pressure.

“Some products may also influence leaf surface characteristics, which can make conditions less favourable for pathogen establishment. When used alongside conventional fungicide programmes, these effects may help support crop performance and contribute to an integrated approach to blight management,” he says.

The favourable combination of Sirius and Trident Plus was applied between 2 July and 30 October 2025 with a spray interval of between 7 to 10 days. 0.5l/ha of Sirius was combined with 3l/ha of Trident Plus.

“To see both yield improvements and a reduction in blight using this rate of application makes the use of biostimulants both a sustainable and cost-effective option. A healthy, stress-free plant is more resilient to both biotic and abiotic stress, which may help crops better tolerate disease pressure when used alongside conventional fungicide programmes,” concludes Mr Rodger.