A new beneficial insect attractant is promising to bolster the IPM toolbox to help growers combat aphids and therefore reduce the threat of the viruses they can transmit. CPM learns about Apthena.
“It’s an enabling technology rather than a straight solution.” PROFESSOR TOM POPE
By Janine Adamson
Instead of developing a product to directly control insect pests such as aphids, a new concept is aiming to achieve the same results, but by making the most of what already exists in nature.
The solution – a beneficial insect attractant – flips the concept of control on its head. Rather than being a new ‘icide’, or even a biological equivalent, it works by manipulating the behaviour of natural enemies, helping to entice them into the crop earlier.
Launched by BASF, Apthena contains the organic signalling compound (E)-β-farnesene (EBF) – an alarm pheromone used by aphids that also attracts beneficial predators and parasitoids, including ladybirds, lacewings and some parasitic wasps.
“EBF was first discovered in the 1970s,” explains BASF’s Rob Storer. “It operates between aphids, between the aphid and the plant, or between the aphid and its predators.”
At a basic level, EBF signals danger, prompting aphids to flee or stop feeding. It also acts as a semiochemical kairomone where EBF is released by aphids but instead attracts natural enemies. “Because beneficials can use this to their advantage, exploring EBF as a kairomone has been our primary interest,” adds Rob.
However, while Mother Nature can easily apply the benefits of EBF, recreating this as a practical solution for on-farm use was a different matter, notes Rob. “EBF is a volatile compound and degrades rapidly, meaning we had to find a successful delivery mechanism.
“So what makes Apthena unique is its proprietary formulation – it’s been developed using microencapsulation technology for controlled release over 20-30 days. By encapsulating EBF in its vapour phase, it’s then released into the air by diffusion,” he explains.
Initial field trials suggest in sugar beet, Apthena can reduce the presence of aphids by more than half (from 2% to 0.5%). Then in peas, the product increased the quantity of plants containing beneficial insects by 18%.
Equally, in controlled laboratory conditions, ladybirds exhibited a significant preference for air containing Apthena – opting to move toward the source of this odour more frequently than for the controls.
Harper Adams University’s Professor Tom Pope believes Apthena has the potential to either draw natural enemies into a crop early, or, encourage them to remain in the area for longer. However, it shouldn’t be used in isolation. “We have to make intelligent selections of compatible IPM tools – those that deliver the best outcome for a profitable crop while posing the least impact on the environment,” he says.
“Apthena can’t provide crop protection alone, but used alongside other methods such as wildflower margins and buffer strip habitats, can attract more beneficial insects into the crop at a potentially earlier time than they’d ordinarily migrate. It’s an enabling technology rather than a straight solution,” stresses Tom.
According to Rob, Apthena should perform particularly well in scenarios where there are already high levels of beneficial insects. “Then it’s a case of manipulating their behaviour with EBF, which should then help to suppress aphid populations.”
With this in mind, the product should be applied when natural enemies are already present and active. Equally, growers should be mindful if using non-selective insecticides in the rotation.
In the main, Rob believes the main barrier to its success will be grower acceptance. “It fits across all cropping systems, but the biggest challenge will be the willingness to adopt the technology on-farm. It’s likely the protected horticultural sector will be its initial breakthrough, as these growers purposefully release mass-reared populations of beneficials so have an instant use case.”
BASF recommends applying Apthena at intervals of 14 days at 0.3-0.5 l/ha with water rates of 100-300 l/ha. Its rainfast within 24 hours, requires no buffer zone or maximum application limit, and so should prove a flexible addition for existing IPM strategies, concludes Rob.
This article was taken from the latest issue of CPM. Read the article in full here.
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