Posted: October 24, 2017

Costa Rica is deservedly famous for its impressive national parks, tropical rainforests, and beaches. Costa Rica is also known as a major exporter of coffee, bananas and pineapples, and most people are probably vaguely aware that this implies large scale monocropping. The country is less known, however, for being one of the largest consumers of pesticides per area in the world, not only on – often vilified – monoculture plantations but also on smaller farms. Up to a third of the fruits and vegetables destined for local consumption in Costa Rica are currently exceeding established limits for pesticide residues. Is this an inevitable price that we’ll just have to pay for ‘feeding the world’ by means of industrial agriculture?

Alternatives exist and business as usual is hardly an option, if we want to feed a growing population without wrecking ourselves and the planet. Research shows that agroecological practices, such as soil conservation, crop diversification, or integrated pest management are far more resource efficient, and in some cases even more productive than industrial agriculture. But how do we implement agroecological practices in a local context? How do we educate producers and consumers? And ultimately how do we upscale sustainable practices in terms of area and market shares? The key is research. If you want to increase agricultural production you either follow the current by intensifying the application of agrochemicals, or you intensify the knowledge about the agroecosystem that exists on your farm. One key component of that system is ‘pests’ and diseases. They may consume more than 15% of global crop production. So, you’d better know your bugs.
We have started to grow our mangoes and oranges organically 6 years ago. Since then, admittedly, production has dropped by more than half with the oranges doing somewhat better than the mangoes. The good news is that our knowledge base is growing, as we have monitored the occurrence of ‘pests’ and diseases along with meteorological data from the beginning.

This semester, students designed and conducted field experiments over several days with the goal of putting our accumulated data to work and deepen our knowledge on how we can improve tree health and fruit production organically. Teams swarmed out to collect field data, design insect traps, and / or they crunched large amounts of numbers from our growing data bases, along with studying the existing literature. In the past, not all our prevention and control strategies have worked. Leaf cutter ants have remained admirably resistant to our attacks, which involved working diatomaceous earth and compost into their nests. But our research now reveals possible weaknesses in other ‘pests’ and or diseases. The bizarre scale insects for instance, soar in particularly dry years and appear to have mutual relationships with certain ant species. Scales in turn promote fungal diseases. So, controlling scales (which can be easily done, e.g. by applying soap) will also decrease fungal infections. Another example is fruit flies, which appear to fall for high sugar concentration bait in traps.

It is amazing to see how invested students are in working on their projects. People can get quite passionate about statistically significant (or not significant) results, when they are analyzing data that represent the effort of several hours of fieldwork or of sorting through data bases. Before you know it, you’re getting a serious kick out of doing stats. And passionate researchers are what we need to tackle the central questions of our time.

→ Sustainable Development Studies in Costa Rica