New era for in field biocontrols
Biocontrol of insect pests stands on the cusp of a new era, with the development of exciting technology offering the potential for highly-selective species specific targeted treatments, using an entirely naturally occurring mechanism.
Speaking at the latest Farmers Weekly Future Farming lecture, supported by Syngenta, Max Newbert, Syngenta insecticide specialist, highlighted future opportunities created by the company’s development of RNA-based biocontrols.
'What's Next for Biocontrols?' speakers: Max Newbert; Professor Simon Leather and Dr Rob Jacobson.
Utilising selected fragments of RNA with identical sequence to an insect pest’s own RNA sprayed onto the crop, will, once ingested by the target pest the biocontrol agent can prevent protein synthesis within the insect’s cells and effectively kill it before the crop is unduly damaged. “As RNA is naturally occurring everywhere it is not introducing anything new to the environment,” reported Max. “Furthermore, since all RNA is unique to individual species, it has no effect on any non-target organisms.”
He demonstrated trials with Colorado Beetle in potatoes offered complete control and protection of the crop, when untreated plants were decimated in hours. Also, the research trials on a crop scale had shown that RNA biocontrols have be developed to target individual pests, or combined together to counter a range of pests, whilst still leaving non-targets – including beneficial predators - unaffected.
Max identified that RNA products can overcome some of the issues with existing biocontrols, including having an immediate effect without having to wait for the predator numbers to build up, for example. Virtually all existing biocontrol only offer a suppression of pest populations, whereas RNA products could offer higher levels of control, at or above existing chemical options.
Furthermore, with new formulation technology , the RNA products have been developed to remain effective for longer, to move systemically in the crop plants - to target sucking insects, as well as chewing pests - and even for take up and efficacy in the soil. They can also be easily applied with existing application techniques.
“Finding new chemical actives is increasingly difficult and highly expensive,” said Max. “We are losing existing products to regulatory hurdles at a rate of four removed to every one new ai registered. Biocontrols can offer real and viable alternatives to fill some of the space being lost from conventional chemistry.
“We do need to develop the regulatory process and the practical implication and utilisation at a farm level for successful introduction and use of the technology,” he said. Max pointed out that there was no timescale for introduction in the UK, with products currently in development primarily aimed at crop pests of the US and South America.
Professor Simon Leather, of Harper Adams University College, highlighted that future developments in precision agriculture could prove entirely compatible with more effective use of biological controls. He cited the potential for the College’s development of an artificial nose that could ‘sniff-out’ the volatile pheromones of individual plants under pest or disease attack, combined with drones that could deliver topical hot-spot application of microbial biocontrol solutions, for example.
For the future, gene sequencing plant breeding techniques, to develop crops with greater natural immunity to pest or disease, could slow down development of a pest that would enable biocontrols to work more effectively, he believed.
He also reported the College’s research into tracking slugs that would give a better understanding of habits that would enable better application of biocontrol nematodes, for example.
“With the right levels of research support and funding, we are at a position to look at field-scale trials and evaluation of crop production that could be implemented almost immediately,” he said.
Also presenting at the Future Farming lecture, What's next for biocontrols?, independent pest management consultant, Dr Rob Jacobson, highlighted the history of implementing biocontrol use in glasshouses had some important lessons for wider application in field-scale crops.
“We quickly found that by successfully controlling one target pest with a biocontrol, meant that a host of secondary pests that had hitherto been controlled with a broad-spectrum insecticide programme, suddenly became pest in their own right,” he said. “Knowing your pest spectrum is crucial.”
Rob pointed out that the adoption of bumblebees for pollination in glasshouse tomato production – which was essential for economic production in the UK - precluded the use of broad-spectrum insecticides.
“In glasshouse tomatoes we are typically looking at eight pest species occurring simultaneously, under conditions that are often perfect for pest development, and over a long growing season,” he advised. “It’s a highly complex and dynamic interaction, so a change of any one factor will have implications for others.
“It requires an immense amount of skill, knowledge and constant monitoring to keep it all working smoothly.” Staff training was imperative for biocontrol to be successful, he advocated.
Rob also pointed out that, in his experience, the use of biocontrols was overall more expensive than conventional chemical control, which presents an challenge for the industry and for consumers as to who would pay for their introduction.
He added that, since traditional biocontrols typically only offer suppression of the pest, with the aim to keep populations below the level of economic loss, – and the fact that the reliability of existing biocontrols is subject to variable environmental factors, most pests require at least one secondary line of defence that can be brought into action as a safety net, if things start to go wrong.
“There are always new challenges for biocontrol: new pests arriving; new cultivars that are more susceptible to pest or disease and require earlier intervention; the loss of target specific chemicals and resistance, plus we are still learning how to get the best results. All these challenges, and more, will face the widespread field use of biocontrols,” he added.