A greater focus on holistic plant health will be more important than ever to address gap filling in vegetable root crop agronomy programmes, according to Simon Jackson, Syngenta Field Technical Manager.

Speaking at the industry Carrot & Onion Conference last week (27 November), he said: “We do have exciting conventional chemistry in the R&D pipeline and working through the legislative framework. However, developments in biologicals are already offering an important bridge in crop agronomy and nutrition strategies.”

He urges that growers and agronomists will need to take all the best elements of existing cultural controls, including varietal selection, rotation and nutrition, and then add in new proven products and technologies that will deliver more consistent yields and crop quality. 

“There’s no get out of jail card that some fungicides historically offered,” he warns. “New biological technologies typically have to be utilised earlier in the strategy, and before issues are encountered.” 

Simon notes that Maxicrop biostimulant trials and growers’ experiences have shown hugely beneficial results for carrot and onion crops when under periods of stress at key points in the growth cycle. “There has been up to a 10% yield increase and a greatest proportion increase in 30-35mm roots in VCS carrot trials,” he said. Other trials results have been less evident, which emphasises the importance of timely and tailored use of products to address specific stresses.

Syngenta vegetable crop research also pinpoints how biological products could complement existing chemistry to give prolonged results through the season. If a conventional fungicide treatment at planting, for example, provided efficient control and reduced pathogen numbers through to mid-summer, then biocontrols could maintain effects through to winter harvesting, when the original fungicide had declined. 

“As we research more about the products involved and understand where they are working in the plant’s biochemistry, we can be far more precise in recommendations for use,” he advocates.     

Better use of disease forecasting and predictions of stress pressures can achieve appropriate application timing to achieve effective results. As well as greater emphasis on application techniques to get the best performance from products where leaf coverage is essential.

“The good news is that fresh produce growers are typically well versed in the techniques involved,” he believes. “Many have already invested in equipment and systems that are well suited to the IPM approach.”

Nutrient capture

New biostimulant technologies offer potential to enhance vegetable root crop growth right from the start and through the growing season, advises Simon Jackson. Already well proven in other crops, including cereals, maize and potatoes, carefully selected bacteria species can contribute to both the crops’ phosphate and nitrogen needs. 

Nuello iN seed treatment includes two unique endophyte bacteria that fix atmospheric nitrogen into a form readily useable by the growing plant. One of these bacteria, Curtobacterium Salicaceae, is also capable of mobilising soil insoluble phosphate to be available for seedling rooting and establishment.

Furthermore, the foliar applied Vixeran is a highly efficient atmospheric nitrogen fixing bacteria Azotobacter Salinestris, that colonise roots and the soil biosphere. This  has been shown to contribute N equivalent of up to 30 kg/ha in crop growth and yield.

“The rooting enhancement seen with Nuello iN in cereal crops could offer great potential for root crops, especially on the premium sandy soils where nutrient retention can be a challenge,” Simon suggests.

Further research and growers’ split field trials are also planned to identify the optimum timing for foliar Vixeran applications and assess response to either reducing artificial N applications, or using the more consistent N supply to promote stronger growth and yields through the season.

Both technologies can be readily integrated with conventional agronomy programmes, alongside existing seed treatments or tank-mixed with fungicide applications. Also, registered with OF&G (Organic Farmers and Growers) certification the products can be used to enhance the reliability and performance of organic growing systems.