“Under the Spanish Sun”

A study into the safety of neonicotinoids is being carried out in Spain

A multi-year honey bee monitoring study in sunflower has been launched in Spain in 2015, aiming to investigate the relationships between bee health and advanced plant protection technologies in order to ensure the co-existence of agriculture and apiculture. Both activities entail remarkable socio-economic impacts in Spain. Bayer is fully committed to sustainable agriculture and, therefore, is contributing to this study.

“Under the Spanish Sun”


// The use of the crop protection products clothianidin and thiamethoxam in bee-attractive crops has been restricted in the European Union since 2013.

// Bayer and industry partners are supporting bee researchers who are carrying out tests in Spanish sunflower fields to determine if these crop protection products have any impact on honey bee colony health.

The golden age of oil and honey

Spain is an important producer of honey: Its honey bees produce around 33,000 tons of honey each year – roughly 15 percent of Europe’s total output. Sunflowers are an important crop in Spain due to the valuable oil that can be extracted from their seeds. Balancing the protection of pollinators, like the honey bee, with productive agriculture is another example of Bayer’s commitment to “Science For A Better Life”.

Researchers dressed in white protective clothing and surrounded by thousands of honey bees are at work in the middle of a huge sunflower field. They are removing honeycombs from the beehives lined up across the field and recording the number of bees and brood combs they find. Small samples are taken from the individual combs, which are then packed up ready for detailed analysis back at the laboratory. The researchers are carrying out this work to determine the honey bees’ level of exposure to the plant protection products used on the crops in the field. Bayer has teamed up with bee researchers from the University of Córdoba, Spain’s lnstituto Nacional de lnvestigación y Tecnología Agraria y Alimentaria (INIA), and industry partner Syngenta for this large-scale study – the first of its kind to be carried out in Spanish sunflower fields.

The aim is to investigate if there is any effect of seed treated with the substances clothianidin and thiamethoxam on the health of bee colonies. “We are carrying out an in-depth study of these bee colonies over a period of three years. Assessments are made twice before the beehives are installed in the fields, twice during the crop pre-flowering season, twice more when the flowers are in bloom and then three times after bloom – the last when the beehives have overwintered,” says Dr María Dolores Hernando of the Departamento de Medio Ambiente at the INIA. “We are looking at wax, honey, pollen, bee larvae and adult bees.”

The motivation behind the study was the EU-wide restriction in certain crops of the use of these two neonicotinoids back in 2013, due to suspicions they could be harmful to honey bees and other pollinators. The evaluation on the basis of which the restrictions were implemented is still being intensively debated, however, and the restriction is having negative consequences for farmers, who now lack highly effective means of protecting their crops against destructive pests.

Sunflower cultivation in Spain
Agustí Soler, Food Safety and Good Agricultural Practice Manager at Bayer, coordinates the input of Bayer to the Spanish sunflower field study.

Agustí Soler, Food Safety and Good Agricultural Practice Manager at Bayer, coordinates the input of Bayer to the Spanish sunflower field study.


Sunflowers are important for both farmers and beekeepers in Spain. In recent years, farmers have cultivated roughly 800,000 hectares for sunflower production – bringing in around 350 million Euros in 2013. This is mainly a dry land crop – only ten percent of the cultivated surface is irrigated. Owing to its ability to develop taproots the crop is capable of penetrating soil to a depth of four metres. Sunflowers bloom during summer, when high temperatures and water scarcity limit the development of wild flora, resulting in depleted sources of food for honey bees. Therefore, beekeepers consider this crop a valuable source of nectar for their hives, which are often sited in the vicinity of sunflower fields during the hot and long summers of central and southern Spain.

“Sunflower seeds treated with insecticide allow for early sowing, which in turn boosts yields and farmer’s income,” says Agustí Soler, Food Safety & Good Agricultural Practice Manager at Bayer Iberia. Previous research conducted in Spain has shown the absence of a correlation between small residue concentrations of insecticides in stored pollen in beehives and colony failure. “Nevertheless, large-scale field trials in treated crops, addressing potential effects of neonicotinoid seed treatments on honey bee colony vitality and survival, have never been conducted in Spain,” says Soler.

That is why Bayer and Syngenta decided to finance the current field study, which began in February 2015. Both companies provided sunflower seeds that had been treated with the substances in question.

“We chose sunflowers as the test crop because bees collect a particularly high quantity of pollen and nectar from these plants in comparison to other field crops, such as corn,” says Germán Canomanuel, Corporate Relations Manager at Syngenta in Spain.

“To avoid compromising the results, we had to ensure there were no other sunflower fields within a two-kilometer radius. This was no easy task,” explains Canomanuel. The research partners chose fields in the southern province of Cádiz in Andalusia and in the south of the regions of Extremadura, Ciudad Real and Madrid. The combined area of all fields equates to some 24 hectares.

"We positioned the beehives in the fields,” says Professor Dr José Manuel Flores of the Departamento de Zoología at the University of Córdoba. “A total of six bee experts from the university are responsible for assessing the bee colonies. The project partner INIA analyzes and evaluates the honey bees’ state of health.” The data gathered in Spain should help to complete the data bases available for the assessment of potential risk of neonicotinoids to bees. Farmers in many European countries have a keen interest in the results: If the substances are shown to have a safe use, the results can feed into the ongoing regulatory process, perhaps to the point where these products can once again be used to protect crops such as sunflowers against pests and thus help provide a more sustainable future for agriculture.

Spain is home to the most beehives in Europe: Some 2.5 million colonies are found here – 18 percent of the continent’s honey bee population.

Spain is home to the most beehives in Europe: Some 2.5 million colonies are found here – 18 percent of the continent’s honey bee population.



Pooling Knowledge in Research

The cooperation between industry partners and the various project partners is critical for the overall success of the field study. Dr María Dolores Hernando of the INIA, Germán Canomanuel of Syngenta, and Professor Dr José Manuel Flores of the University of Córdoba bring together many years of invaluable experience and knowledge, complementing one another’s expertise perfectly.


What is the basic situation regarding bee health in Spain?

Dr Hernando: Various factors have been identified in causing an increased mortality of pollinators. The current challenge is to consolidate research on the issue using risk weighting, and the evaluation of potential convergence between the key factors that affect the abundance of bee populations.

What is the main goal of the study?

Professor Dr Flores: We as scientists hope to get reliable field data on honey bees exposed to treated sunflower under realistic conditions. Our team of six researchers is keeping and assessing the honey bee colonies that collect pollen and nectar from sunflower blooms grown from seeds treated with neonicotinoid insecticides.

What is your role in the project?

Dr Hernando: The INIA research group is in charge of evaluating residue levels of plant protection products to develop a robust and science-based understanding of the implications of the use of these products. This ongoing research aims to gain additional monitoring data and assess whether there are unacceptable risks for honey bee colonies.

What are the prospects for the future?

Germán Canomanuel: This project will last for three years and is part of a European initiative supported by Bayer and Syngenta that includes studies in oil seed rape and sunflower. I am sure that both companies will continue providing their support with their high standards of technology, expertise and know-how to help deliver the necessary knowledge to take decisions based on science and real facts.


Dr Maria Dolores Hernando


Germán Canomanuel

Prof. Flores

Professor Dr José Manuel Flores



The large-scale field study in Spain is running until spring 2018, after which researchers will analyze the gathered data.
The results of the joint Bayer/ Syngenta-supported study will provide additional data about potential side effects of neonicotinoids, clothianidin and thiamethoxam, on honey bee colonies foraging in sunflower fields. It will make an important contribution to the bee health debate in Europe.


Ensuring Bee Safety in Sunflower Fields

In Spain, sunflowers are an economically important crop that needs protection from pests. To ensure that the usage of crop protection products does not harm honey bees, Bayer has teamed up with academics and industry partners for a large-scale field study.


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“Under the Spanish Sun” A study into the safety of neonicotinoids is being carried out in Spain

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