January 24, 2022

Farming right next to protected areas is possible with pheromones

The Ebro Delta is one of the most important wetlands in Europe. It is well worth protecting. There is just one problem. The Ebro Delta is interspersed by marshes and paddy fields that traditionally are treated with pesticides to kill insect pests. The futility of this biological tug-of-war is clear for all to see. But what to do? Spoiler alert – the solution involves pheromones.

The Ebro Delta of Spain spans more than 30,000 hectares (320 km2). Its lagoons, marshes, pans and beaches shelter 77 protected plant and vertebrate species. With more than 343 species of birds recorded, it is a haven for birdwatchers. Not surprisingly, part of the area is a designated Natural Park in Spain and protected under the EU Birds and Habitats Directives, the Ramsar Convention and UNESCO. 

Unfortunately, the 7,800-hectar Natural Park is surrounded by 22,000 hectares of rice, a favoured crop of the striped rice stemborer (Chilo Suppressalis). This is a pest notoriously difficult to control. On hatching from the eggs, the larvae quickly bore into the rice stem, where they stay until they emerge from the pupae, making them difficult to control with traditional insecticides. As a result, the Ebro Delta was sprayed with hundreds of thousands of litres of aggressive insecticides such as organophosphates in the 1980s and 1990s, killing off pests and beneficial insects alike, along with birds, fish, amphibians and other lifeforms.  

Something had to be done, and that something became the introduction of pheromone-based mating disruption. Pheromones are natural molecules secreted by moths in particular to attract a mate. If a farmer disperses the same pheromones in a field, the insects’ I-am-here pheromone trail is veiled, and they can’t find each other. No mating means no eggs and no plant-munching larvae. 

The transition from insecticides to mating disruption in the Ebro Delta happened gradually in cooperation with SEDQ, a Spanish company specialising in biological pest control solutions based on pheromones, which BioPhero is partnering with in the PHERA Project. The growers began with mass trapping in 2000, using pheromone-loaded traps to attract the moths, combined with aerial spraying if needed, and only if needed. In 2012, they introduced mating disruption, and by 2015, all 22,000 hectares of rice were cultivated using mating disruption only. 

The results speak for themselves. Today, the growers of the Ebro Delta have almost eliminated the use of pesticide – only a few percent of cultivated area need to be sprayed – to the benefit of the area’s fauna. Further south along Spain’s eastern coastline, one finds the Albufera Natural Park, another important wetland surrounded by paddy fields. Here, the growers were a little quicker at embracing mating disruption, spurred on by an impending ban on aerial spraying by 2009. A study of waterbirds in Albufera from 2009 to 2017 found that the number of breeding pairs had increased by over 40 times. 

The pheromone blend used in the Ebro Delta is incorporated into a polymer dispenser together with UV blockers and antioxidants to protect the active ingredient. The growers simply have to place the dispensers on sticks in the field – and only once. Treatment no longer must be repeated, and the biodegradable canes can be left in the field to decompose. It is easy and more cost-effective than conventional spraying. 

The EU-funded PHERA Project is scaling up BioPhero’s fermentation method for production of affordable pheromones at an industrial scale with the objective to make pheromones accessible for pest control in large-scale row crops. The project brings together the fermentation expertise of BioPhero with the production capacity of the Bioprocess Pilot Facility, the pheromone formulation and application skills of SEDQ, ISCA, Russell IPM and NovAgrica, and the life cycle knowledge of Fraunhofer.