SR14 What is known about the impacts of neonicotinoid insecticides?

Neonicotinoid insecticides (NNIs) are broad-spectrum, systemic insecticides with a wide range of uses from crop protection to urban pest and veterinary ecto-parasite control. In arable crop protection, they are used to suppress direct damage by herbivorous insects and indirect damage by insect transmitted viruses.

Rapeseed can be protected from insects by neonicotinoid insecticides. Photo: iStockphoto, copyright: mtreasure

Rapeseed can be protected from insects by neonicotinoid insecticides. Photo: iStockphoto, copyright: mtreasure

Review status

NNIs have become increasingly important for crop protection where there is pest resistance to alternative insecticides such as pyrethroids. They offer long lasting residual crop protection reducing the need for multiple applications, are generally more toxic to insects than vertebrates so increasing operator safety, and are versatile in terms of application method.  These attributes have contributed to an increase in the popularity of NNIs and exponential growth in their use since they were first introduced in the early 1990s.

In parallel with the recorded increase in use of NNIs there have been increasing concerns and debate about the potential negative effects of these insecticides on non-target organisms, particularly on bees. Against this background, in some countries legislators and politicians have been faced with a need to make decisions on the future registration of some or all of this class of insecticides.

Although there have been a number of recent reviews published about the potential environmental impacts of NNIs, many have focused on bees and most have not been conducted systematically. The systematic map with which EviEM will be involved will have a broader scope than bees alone, focusing on all non-target organisms, and will also include socioeconomic consequences of not using NNIs. Neonocotinoid insecticides considered in this systematic map include imidacloprid, thiamethoxam, clothianidin, dinotefuran, acetamiprid, thiacloprid and sulfoxaflor.

The primary objective of the study is to systematically collate and map all the research evidence regarding:

  • Adverse effects on non-target organisms (lethal and sub-lethal effects) and exposure via occurrence of NNIs in various parts of the environment (e.g. pollen, nectar, soil, water, etc.).
  • Mitigation measures to lessen these impacts.
  • Potential environmental, economic, and socio-economic consequences of a ban on this class of insecticides.

The systematic map will provide a broad overview of the available research and describe the volume and key characteristics of the research. It will also identify evidence clusters and knowledge gaps. The systematic map will not extract findings of relevant studies but will extract meta-data on study setting and experimental design. One of the key outputs of the systematic map is a searchable database that will enable users to select studies relevant to sub-topics of interest.

The project was initiated at Harper Adams University with funding from the John Oldacre Foundation under the leadership of Nicola Randall. EviEM will support the project by providing expertise and reviewer time.

Protocol has been published

After consultations with stakeholders the review team has now authored and published a protocol, i.e. a detailed plan for how the map of NNI research is to be conducted (see link in the margin at right).

Searches for scientific literature in databases have been completed, and approximately 22,500 unique articles that potentially could be of interest for this systematic map were found. Now, a screening process is ongoing where we aim to identify the truly relevant studies. When that is completed, the relevant studies will be critically appraised.

Review team

Nicola Randall (Chair), Centre for Evidence-Based Agriculture, Harper Adams University, the UK
Katy James, Centre for Evidence-Based Agriculture, Harper Adams University, the UK
Keith Walters, Crop and Environment Sciences Department, Harper Adams University, the UK
Magnus Land (Project manager), EviEM, Stockholm, Sweden
Neal Haddaway (Project manager), EviEM, Stockholm, Sweden