Agricultural cooperatives in the Ponent regions are working together to develop new strategies to combat the corn spider mite. This pest can dry out corn plants prematurely, potentially halving the harvest. One of the techniques being tested involves releasing predatory mites, known as phytoseiids, which feed on the spider mites, using drones. This method allows for more precise treatment of larger areas compared to traditional manual application.
This biological control system is also being considered as an alternative to chemical pesticides, especially after the Ministry of Agriculture did not authorize the use of abamectin this year, the primary product previously used to control this pest. The spider mite, which is actually a mite and can vary in color, can cause significant losses in corn crops, with its incidence as a pest notably resurging since 2017.
According to Núria Ris, a technician at the Sant Miquel de Bell-lloc d'Urgell Cooperative, the presence of this mite, particularly during flowering in July, causes corn plants to dry out before the kernels can mature, leading to a halved yield. The lack of an effective solution and the European Union's ban on abamectin since 2023 have spurred the search for alternatives.
In response, the Bell-lloc d'Urgell Cooperative, along with other cooperatives in Ponent, are undertaking research projects, including the drone-based release of predatory mites. These initiatives are led by Agrotecnio-Universitat de Lleida and the company Agronatur Biocontrol, with drone applications handled by Agronedia. This year marks the first time drones are being used for this purpose, replacing previous manual applications.
David Valverde, head of insect production at Agronatur and project manager for the drone operations, explains that introducing phytoseiids helps maintain the pest population below damaging levels, although it does not eliminate it completely. The main challenge is ensuring the mites establish themselves permanently in the fields. Once established, the use of abamectin becomes unnecessary, and positive effects are observed quickly. Unlike abamectin, which provides a temporary shock effect, biological predators, if they adapt, offer a more sustainable long-term solution.
