Biodiversity is key to produce watermelons without pesticides – an example from an organic farm

Los Grillos, Spain, March 2023

A sunny day in March is the one chosen for cutting off the Gatinho watermelons (mini striped) that Esther Molina has cultivated on her organic greenhouse farm in Los Grillos without the use of insecticides thanks to conservation biological control. Esther is one of the farmers of the Spanish greenhouse hub of the Horizon 2020 project IPMWORKS led by the hub coach Eduardo Crisol Martínez.

At sight, between bands and aisles, scattered throughout the greenhouse, all kinds of reservoir plants (marigold, immortelle, lobularia, nettle, fennel, sunflower, coriander, among others and of course, cereal bankers) are present. These reservoir plants are not decorative, but fully functional.

Last year was a difficult watermelon and melon season due to adverse weather, abundant rainfall, dark days and haze, so aphids have become a big issue for many farmers. However, Esther has been able to dominate this enemy of cucurbits thanks to the practice of conservation biological control. Conservation biological control is a pest management strategy that supports natural enemies of pests present in the agroecosystem and promotes their effectiveness as predators, parasitoids or pathogens. These natural enemies then regulate the spreading of pests on the farm.

“All I do is taking care of biodiversity. The reservoir plants have been in place since last June, and from my own experience it is the most effective tool. They conserve the environment but also your beneficial insects, which keep the aphids at bay. ” Esther says. She has also been calm despite the bad weather this year. “I have suffered less because I have a great biodiversity, and thanks to bees, bumblebees, but also hoverflies, lacewings and other insects, pollination has neither slowed down nor stopped,” she assures.

Esther is a member of the Spanish greenhouse hub of the Horizon 2020 project IPMWORKS, consisting of a mixed group of 12 organic and conventional farmers which are led by the hub coach Eduardo Crisol Martínez from COEXPHAL. In this hub, the greenhouse farmers exchange their knowledge on applying integrated pest management (IPM) strategies. IPM is based on the combination of a diversity of pest management measures, like prevention or non-chemical control, at the farm level in order to reduce the reliance on pesticides. “On Esther’s organic farm, we can see that with the right combination of pest management strategies the use of pesticides is not necessary to produce agricultural products. It is great to have such an example in our greenhouse hub so that Esther can share her experiences with the other farmers.” Eduardo says.

The sector leader of the cross-cutting organic sector in IPMWORKS, Lisa Sinnhuber from IFOAM Organics Europe, highlights: “As we can see on Esther’s farm, organic farmers are experts in pest management without using pesticides. In organic farming, plant protection is based on the ecosystem services provided by well-maintained and functional biodiversity, as well as preventive measures to be as little dependent on external inputs as possible. As a last resort, organic farmers can use natural plant protection products, but the use of synthetic pesticides and herbicides is prohibited. I hope that this example of Esther’s farm inspires other farmers in IPMWORKS.”

In summary, using conservation biological control, Esther is able to produce high-quality organic watermelons without using insecticides. She is focusing her effort on protecting and enhancing the activity of natural enemies of pests with a wide diversity of plants that provide shelter and food to this noble army.


The Horizon 2020 project IPMWORKS builds a European farm network to demonstrate integrated pest management (IPM) strategies and to promote the adoption of such strategies via knowledge exchange. IPMWORKS coordinates existing networks promoting IPM and launched new hubs of farms in regions or sectors where IPM pioneers were not yet engaged in a relevant network. Hub coaches coordinating hubs will have a major role in facilitating knowledge sharing, coaching farmers to find their own IPM solutions, and organising local demonstration activities.

Contact details:

IFOAM Organics Europe, sector leader of cross-cutting organic sector in IPMWORKS:

Lisa Sinnhuber, Research and Innovation Coordinator