Beat glasshouse pests with biopesticides

The biopesticide industry is growing fast. But is there any substance behind the substances that are being sold for plant protection?

In the past six months of 2012 about US$2bn (£1.25bn) was spent on acquisitions of biopesticide companies by such notable names as BASF (Becker Underwood), Syngenta (Pasteuria) and Bayer CropScience (AgraQuest).

The market in 2012 was estimated to be worth $1.6 (£1bn) at grower level, however, projections estimate that by 2016 that could be in the region of $3bn (£1.9bn).

So what is all the fuss about?

Biocontrols and biopesticides offer a way of reducing the use of conventional chemistry, offering a "greener" and more sustainable way of protecting crops.

As part of the spate of acquisitions, BASF took control of Becker Underwood - a firm that developed products such as Nemasys and Nemaslug.

BASF specialty crops product manager Robert Storer says the products use various species of living parasitic nematodes to control pests such as vine weevil in strawberries and slugs in a range of crops and they are proving a success in fresh produce sectors.

"Specialty crops are the driver, where growers are closer to the end user and have been required to be more dynamic in their crop protection practices," he adds.

Globally, the fruit and vegetable sector accounts for 80% of biopesticide sales and there have been a number of UK success stories.

Loss of pesticide actives from tighter regulation, along with pressure from supermarkets and consumers with zero tolerance for residues on food has pushed many growers away from conventional chemistry and to biocontrols.

Luke Hughes-Burton, herb-growing manager for VHB, says it would be extremely hard to supply his produce without biocontrols and biopesticides.

 
Based in West Sussex, the firm is the largest supplier of fresh herbs in the UK retail market and has reduced the use of conventional chemistry in its glasshouses to minimal levels.

"We have been successfully using biocontrols for pest control for many years and it has been a huge step forward for our business."

Mr Hughes-Burton is using Nemasys for sciarid fly larvae control and Nemasys C for shore fly larvae control, applying the liquid suspension - containing the nematodes - through an overhead gantry irrigator in the glasshouse.

The nematodes then attach themselves to the larvae, killing them within days and reducing the impact from feeding and ensuring no pests make it on to the supermarket shelf.

A higher cost is associated with biocontrols or biopesticides and although Mr Hughes-Burton concedes that they are costly on a pack-for-pack comparison with traditional chemistry, it's not that simple.

"If we have a large outbreak of flies it can push costs up, but with conventional insecticides you would need multiple applications and there is the risk of insecticide resistance also," he explains.

Fly numbers in the glasshouse are constantly monitored and peaks and troughs are identified and the level of nematodes is increased to mitigate high numbers.

Conversely, where populations are low the supply of nematodes can be slowed to a trickle to reduce costs.


"They are used all year round, but the peak of fly incidence is in March, so that's when we release the greatest quantity of nematodes."

Mr Hughes-Burton is also using parasitic wasps to control leaf miners, mites to control thrips, lacewing larvae to predate aphids and biopesticide DiPel (Bacillus thuringiensis) for caterpillar control.

Despite the successes VHB are having with biocontrols and biopesticides, Mr Hughes-Burton acknowledges there are challenges making it work in the wider environment.

"The nematodes would have potential and we have successfully used Nemaslug to control slugs in outdoor chive crops, but natural predators are harder to contain," he explains.

The technology has to improve and biopesticide expert Bill Dunham of Dunham Trimmer - a company that specialises in bringing plant protection products to market - says those improvements are just around the corner.

"Those improvements will see biopesticides take off into the cereal and row crop sectors, with technology such as micro-encapsulation, for example, improving the length of activity natural products have in the field," he explains.

However, it is in seed treatments he sees the initial growth into broad acre crops, with nematicide seed treatments already available for soya bean crops in North America.

"In my opinion, within 5-10 years broad acre growers will start to see the benefits of biological seed treatments, foliar treatments and bio-stimulants," he adds.