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Report finds systemic pesticides not as effective as once thought, cites pest resistance as key reason to end mass uses of the harmful substances.

Overview
A new study published in the academic journal Environmental Science and Pollution Research calls into question the value of neonicotinoid insecticides (“neonics”) in agriculture. The research, conducted by the international Task Force on Systemic Pesticides, reviews more than 200 studies on the performance of neonics in controlling a wide range of insect pests on agricultural crops worldwide, including corn, wheat and many types of fruits and vegetables, as well as the available alternatives.

The study shows that the application of integrated pest management (IPM) principles and practices is affordable and effective. Major highlights include:

• The use of neonic-treated seeds does not increase crop yields in most cases
• Early and reliable detection methods to assess the risks of pest presence exist, at low costs
• Effective strategies are available to protect farmers against economic risks and achieve efficient pest control – e.g., the “mutual fund” (MF) model (described in further detail below), a novel insurance method designed to protect farmers against crop failure
• All scenarios – whether using IPM and/or insurance cover – are cheaper than using neonic-treated seeds

Drawing from studies throughout Europe, the review highlights evidence that widespread use of neonic seed treatments generally has little effect on crop yields because, in many cases, pest populations are below levels that would cause significant economic damage. Moreover, the review finds that the value of neonics is undermined by rapid development of resistance in target pests, and because the insecticides cause harm to insects and soil organisms that are beneficial to agriculture, such as bees and other pollinators.

Other effective alternatives are available and can benefit farmers, because crops cultivated without chemical insecticides may be sold at higher prices (e.g., certified organic produce). These alternatives include better farming methods (e.g., crop rotation, resistant crop varieties), biological control and crop insurance programs that are cheaper than insecticides and that compensate farmers for all events of losses, without placing any pressure on the environment.

Low-cost and reliable prediction method
The TFSP review highlights a model developed in Italy to predict which fields are at high risk of pest problems, in order to appropriately target pest management strategies. A 29-year, large-scale study characterized factors that increase risk of wireworm damage. Assessing the risk of wireworm damage provides a solid basis for identifying farmland that can be left untreated, without any risk of yield reduction – instead of indiscriminately using neonics on a prophylactic basis. In NorthEast Italy, 96 per cent of corn fields do not need any insecticide treatment (because relevant pest threats are not present above the economic damage level).

Novel Insurance Method
Where risks exist, the study shows that a “mutual fund” (MF) insurance model piloted at a very large scale in Italy is a cost-effective approach. It shows that the total cost of damage to maize (e.g., the need for re-sowing and yield loss) plus the MF cost was much lower than the total cost of the insecticide treatments, even when all the fields are left untreated. When adding IPM strategies to the MF strategy, the economic advantage was even greater. In addition to economic advantages, MF avoids the environmental harm associated with the use of neonics.

Evidence of harm
First introduced in the 1990s, neonics and fipronil — another systemic insecticide used in parts of Europe and Asia — are now the world’s most sold insecticides. They are extremely toxic to biodiversity at very low doses because they are watersoluble and very persistent (i.e., do not readily degrade) in soil. This results in sustained and chronic exposure in terrestrial and aquatic environments. Scientists have further reported that extensive and routine application of neonics in agriculture is causing large-scale environmental contamination, including lethal and sub-lethal impacts to bees and other pollinators, as well as soil invertebrates, all of which are crucial to agriculture.

Conclusion

Many governments have been slow to take action on neonics despite evidence of worldwide environmental contamination and harm to many species. Decision-makers frequently justify inaction on the basis that the controversial insecticides are a necessary tool for pest management, and that their withdrawal would cause economic losses in the agricultural sector.
The TFSP’s review of the published evidence shows that alternative integrated pest management methods are available to protect farmers against economic risks and achieve efficient pest control below the economic injury level (Table 1). This latest study proves that neonics can be phased out without further delay to protect bees, aquatic invertebrates and other beneficial organisms, while maintaining agricultural productivity and even increasing benefits for farmers.