Episode 3 of 21: Soybean rust control: A stitch in time…

In this podcast episode of ‘We’ve Bean around the Block’, sponsored by Pannar Seed, host Antony Jarvie interviews his guest Dr Rikus Kloppers about chemical control of soybean rust. In his long career, Rikus has worked on the genetic defense of crops through pathology and biotechnology services and now has turned his hand at chemical protection of the crop. He has a truly 360 degree vision of crop protection, making him the perfect guest for the show. In this episode, the fungicidal control of soybean rust is dealt with by looking at: ‘When’; ‘What’; ‘How’. Control treatments are made after flowering of the crop and before symptoms are visible. A strong case is made for ‘A stitch in time, saves nine’; preventative action is critical for good control of soybean rust. The contrast is made between maize rust and soybean rust, where some Strobilurin products may cause cessation of sporulation in maize rust but not in the case of soybean rust. In terms of ‘What’ to spray, there are 33 products registered for soybean rust control in South Africa. Many of them are combination products with more than one active ingredient. Combining multiple modes of action is an important strategy in fungicide stewardship, and if this is combined with different products in a spraying sequence, it adds robustness and longevity to the programme. The fungicide needs to penetrate down to the lower leaves within the crop canopy to be effective. The ‘How’ this is done is not important, whether it is ground or aerial application, the important factors are good droplet distribution and effective penetration. The direction of new product development is not only to improve effectiveness but also to improve safety. As new genetic traits are added to the crop, the value of the crop increases and thus the protection of the crop yield becomes more important.