Four ways with pesticides

Pesticides graphic-1Pesticides, substances designed to prevent, destroy or mitigate any pest, are beneficial in many ways. They protect crops from infestation, allowing for higher and more stable yields, and they protect humans from insect attack, crucial in the fight against insect-transmitted diseases such as malaria. But they also pose serious threats to the environment and to human health. In response to the concerns over the impact of pesticides on bee populations, for example, the European Union, earlier this year, issued a partial ban on neonicotinoids.

A new special issue of Science, The Pesticide Paradox, through a series of papers, explores the benefits and impacts of pesticides and discusses what more can be done to track pesticide use, reduce our reliance and its impact, and find alternatives.

Track their use and evaluate their impacts

Understanding how and where pesticides are used and what hazards they pose is the first step to minimising their impact. For example, pesticide degradation and its effect on the landscape is little understood, as are the impacts of pesticides on non-target organisms and communities, and on human health and development. One paper shows the alarming impact exposure to pesticides in early life can have on brain development – reducing IQ and causing ADHD-like behavioural problems.

Verger and Boobis in their article, Reevaluate Pesticides for Food Security and Safety, discuss the use and sale of generic versions of pesticides, which account for some 30% of total pesticide sales. As the original producer has little impetus to assess the usage and hazards, these pesticides, despite being more affordable to farmers in developing countries, may not meet internationally accepted criteria. Authors describe how these generic pesticides can be monitored.

Reduce their use

The next obvious step is to minimise their use. For some farmers, prudent use of pesticides can boost crop production but for others, particularly under intensive farming, pesticides are over-used, sometimes creating new pest problems or pest resistance. For example, in Indonesia where the Brown Panthopper became a serious pest of rice, pesticides were found to be ineffective because they also killed parasites and wolf spiders, natural enemies of the Brown Planthopper. Use of Integrated Pest Management, a combination of pest control techniques, reduced the use of pesticides while at the same time raising rice yields. More holistic methods of pest control, however, can be knowledge-intensive. In Vietnam, large-scale experiments and use of radio have shown farmers how to use pesticides more judiciously to increase their profits.

Develop more benign pesticides

Reducing pesticides entirely is unlikely and perhaps, given the benefits they convey, unwarranted, so ensuring pesticides are selective for target organisms is crucial. Cutting edge technologies can help produce pesticides that reach high regulatory requirements, are environmentally benign and cost effective, and many of these are already in development.

Green chemistry, for example, is growing as an industry and could produce more environmentally benign pesticides. Green chemists employ the tools of traditional chemistry, but use renewable resources as their building blocks. Instead of ending up with hazardous toxins, they use less hazardous solvents and aim to avoid detrimental impacts altogether. Over the past 15 years, green chemistry inventions have reduced hazardous chemical use by more than 500 million kilograms.

Find alternatives

As well as ending over-use of pesticides, we can reduce pesticide use further if there are viable alternatives. Eric Stokstad investigates a diversified approach to weed management including non-chemical techniques such as seed burning. Agrocecology is just one approach that utilises the relationships between organisms in a farming system to minimise pest problems. Genetic technologies are also being used to develop long-lasting disease resistance within plants.

Clearly there are a lot of options for minimising the harmful impacts of pesticides and there is a lot of public pressure for governments to regulate pesticide use. We will require significant political leadership and understanding if pesticides are to be less impactful and we need solutions tailored to farmers themselves if food production is to be maintained.

PICTURE CREDIT: G. Grullón/Science.



  1. Reblogged this on AGRI-NEWS.

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