Green Headlands offer IPM pest check
Green Headlands create the opportunity to enhance the numbers of beneficial predators in the field, as well as a potential barrier to hold up pest species from infesting or infecting crops, advocates Syngenta Insecticide Technical Manager, Dr Max Newbert.
Over 330 hectares of the Syngenta Operation Pollinator Green Headland seed mix was planted in 2020, an equivalent of over 550 km of six-meter margin.
That had doubled the area from previous years and demonstrated growers’ interest in enhancing soil health and harnessing the opportunity for IPM benefits, he said.
“The original concept behind Green Headlands, instigated by Syngenta with ASDA, IPL and Kings Seeds, was to utilise uncropped areas around potato and vegetable fields to protect soils, increase fertility and increase biodiversity.
“Through extensive research we’ve demonstrated it ably achieves all those objectives, as well as a potentially important role in IPM.”
Detailed entomological monitoring of Green Headlands in 2020, including analysis of 10,000 insects, revealed the areas were a magnet for flying insects, including many pollinating and beneficial predator species. The work has shown it can significantly enhance what is naturally in the environment.
“From the monitoring it has shown the mix typically holds a ratio around of 3:1 of species that might be considered pests, to those that are known predators. However, since each predator would eat 100-120 pests that is a very good balance in the natural environment,” advised Dr Newbert.
“Importantly, there is no indication of the Green Headland attracting or creating any reservoir of pest species, or propagating the incidence of virus.”
Dr Newbert has also carried out trials on the potential of Green Headlands to mitigate virus transmission from aphids, essentially acting as a barrier to intercept aphid migration. Some of those aphids would be caught by predators, whilst others held up in the mix would lose the propensity to transmit non-persistent virus.
Research had shown evidence the technique could prove effective in carrots, and another potential tool in the armoury for potato growers, he reported.
One of the challenges is how to extend the benefits of the margin out into the crop and exploring the optimum ways to integrate into on-farm practice?
He highlighted the monitoring had indicated that 25 meters into the crop there was a 90% drop off in the numbers of insects found in the new habitat. That would suggest a Green Headland strip running at 36m tramlines through the crop, for example, could move the beneficials evenly throughout the field.
“It has also demonstrated that the Green Headlands can work effectively alongside existing agronomy practices and provide another layer of resilience against pest populations.
“The next step to develop IPM solutions is to evaluate thresholds for predators and that balance with pest numbers. That could mean growers and agronomists can become more reactive, with interventions only as and when pest numbers are building or reach unacceptable levels.”