Wetenschap - 24 juni 2010

Trailblazers for the good bug

Joop van Lenteren, an international authority on biological crop protection, delivered his farewell lecture as professor of the Laboratory of Entomology in mid June. He criticizes the approach to pesticide use in farming. ‘The Ministry of LNV isn’t doing anything about it.’

‘We have to step up efforts in using biological pest controllers in outdoor horticulture, orchard farming and field crop cultivation. The crop in these areas is like an incubator baby which cannot do without pest control agents. This problem needs to be tackled by new fundamental research involving a combination of plant breeding and biological pest control to develop robust crops and to reduce pestilences. We had plans to carry out such research, but we did not have enough financial support. The Ministry of Agriculture, Nature and Food Quality has left us to our own devices by not making pesticide reduction a legal requirement. It has chosen instead for a agreement in which the pesticide lobby and the conservative farming lobby can argue the toss and discuss terms with one another.'
Joop van Lenteren, who delivered his farewell lecture as professor of Entomology, remains a proponent of biological crop protection measures and a critic in farming policy. Insects were just unpopular little creatures to be killed with poison when he set out in the nineteen seventies to study them.  It was little known then that they could play a useful role in pest control in agriculture and horticulture. It was Van Lenteren who blazed the trail for research into biological crop protection.
Bad bugs
Other pioneers in biological pest control conducted mainly applied research, by collecting insects from nature to find out if they feed on bad bugs, and then releasing them in areas where bad bugs proliferate. Van Lenteren found this useful, but not good enough. ‘It was trial and error. There are hundreds of natural predators for a pest insect. How do you select the best and how do you know if the insects will differentiate between good and bad bugs?' Van Lenteren decided that fundamental research was needed to make a breakthrough, and put his words into action from 1983 as professor of Entomology in Wageningen.
Via a series of experiments, he showed that insects have very specific preys and can learn from experience. He discovered too that the aroma of de prey can lead the hunter on its trail. His colleague Marcel Dicke discovered that plants lure natural predators to them as soon as they are plagued by pest insects. ‘We now understand how a parasite gets hold of a host and how it determines if it's got the right one', Van Lenteren lectured at his departure. His research has produced criteria which a good pest controller should have, for example, to counter plant lice, caterpillars, spider mites, thrips and white flies. A biological pest controller has to be specific, can eradicate pests in big quantities, detect new pests quickly, get to work where pest attacks are most serious, has no negative side-effects on other useful creatures and can be reproduced quickly by companies introducing biological pest controllers into the market. ‘Various countries make use of this risk analysis at present', adds Van Lenteren.
Industry
Karel Bolckmans, R&D director of Koppert, presented a Life Time Achievement Award to Van Lenteren at his departure. Koppert, located in Berkel-en-Rodenrijs, is a market leader in the world of biological pest controllers.
‘Van Lenteren is an international authority in the area of biological crop protection using insects', says Bolckmans. ‘This is because of his research work, which has enabled us to understand the ecology and biology of natural predators much better. Secondly, he has brought science and industry together and convinced companies to cooperate. Thirdly, he has put a lot of effort at the end of the nineties into developing an environmental risk assessment for biological pest controllers, by finding out if a newly-introduced creature can harm the ecosystem. The companies did not understand this at first, but Van Lenteren has influenced new legislation such that ecological research is taken into account. He is critical, but always with the best of intentions. He keeps advocating biological pest control instead of the use of poison, as Joop calls it all the time.'
Van Lenteren himself does not approve of the lobbying strength of the biological crop protection sector. ‘We are not aggressive enough in defending our work. The 250 million in market value are peanuts compared to the 30 billion euros spent on pesticides annually. The pesticide industry has a powerful lobby against biological crop protection, because you can't take out a patent on biological controllers and the profits are lower.' The outcome of this is visible to Van Lenteren. ‘The use of pesticides is growing again. We were trailblazers, but the Ministry of LNV has withheld its support for biological crop protection since 2003. Very disheartening.'
Bolckmans also feels that the Netherlands was ‘the epicentre' of biological pest control in the world. ‘That was because of the good cooperation among research, horticulture and industry sectors. When cucumber breeder Jan Kopert set up our company in 1967, he had already been working together with the experimental station for horticulture in Naaldwijk on the use of predator mites. Wageningen UR Greenhouse Horticulture in Naaldwijk is still a major contributor, but we watch with a lump in our throats as the research into biological crop controllers at Entomology slid into the background', he professes.
Silver platter
Van Lenteren does not agree to this. ‘Koppert of course wants natural predators presented to it on a silver platter. But the company has twenty researchers in its employment to search for new pest controllers. Our task is fundamental research and methodology development. In greenhouses, biological crop protection has already become the standard. Market gardeners are very progressive; they embrace the reduction of poison.' Another positive development, Van Lenteren feels, is that supermarkets are intensively intervening in the use of pesticides in agriculture. ‘They demand residue-free foodstuff and are starting to promote integrated crop protection.'
He is optimistic about the future. The European Union will remove 750 of the one thousand currently used pesticides from the market. ‘In twenty years' time, one third of crop protection will be biological', he predicts. ‘Another one-third will be protected by having resistance against pests built into the plant. That leaves just one third more to be tackled by other clever methods, which will include a bit of selective chemical pest control.'
400 billions
Hundreds of biological pest controllers are responsible for sustainably suppressing 165 pestilences in the world. Chief among these controllers is the ladybird from Australia, which has been protecting citrus plantations from the devastating plant lice in California and fifty other countries for 120 years. ‘The ladybird offers permanent protection, and you don't have to do anything else', says van Lenteren. He estimates the cost of this classic form of biological pest control at several billions of euros a year. ‘If you were to kill all the natural predators of crop pests by spraying, you would need to spend 400 billions on pesticides annually.'
 

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