Oilseed rape in crisis: can fresh approaches to pest management save this vital crop?

Bright yellow fields of oilseed rape are becoming a rarer sight in western Europe as growers struggle to control pests with an ever-limited arsenal of chemical products. In some areas of the UK for instance, the crop area has fallen by as much as 70%. Yet demand for seed oils is increasing. Recent political turmoil, such as the war in Ukraine, has only exacerbated the supply problem. Without effective pest control strategies, further declines in production seem inevitable.

It is timely, then, that a special edition of the journal Pest Management Science seeking to shed some light on new integrated crop protection approaches for oilseeds has been published this month. The focus is on the development and use of more sustainable alternatives to synthetic pesticides. These are urgently needed to ensure sustained and sustainable production of oilseed crops. 

Oilseed plants have a very important place among cultivated crops. They provide vegetable oil and high-energy animal feed, thus provide a healthy option to address the need for fats in the diet of humans and animals. Oilseeds are also increasingly used as biofuels and significant rises in demand have resulted in vast increases in their cultivation globally. 

″This popularity has led to proliferation of the pests that affect the crops, in particular insects that feed on the plants and pathogens that cause diseases,″ said lead editor of the special edition Dr Sam Cook, a crop protection specialist at Rothamsted Research. ″Like most of arable agriculture, pest control in oilseed crops has become reliant on synthetic chemistry but overuse has resulted in serious problems including pest resistance and environmental pollution.″ 

A working group (WG) of the International Organization for Biological Control (IOBC) was formed in 1990 to address these issues. The Special Issue of Pest Management Science is inspired by the biannual meeting held online in 2022; and contains papers presented at this meeting as well as contributions from other members of the rapeseed research community. 

The issue focuses on integrated pest control in rapeseed, mainly oilseed rape (Brassica napus),which represents 60% of the current oilseed production of the European Union. This makes the EU the biggest producer of oilseed rape worldwide. Its main pests include cabbage stem flea beetle (CSFB), pollen beetles and fungal diseases like Phoma leaf spot and stem canker.

″In many field situations the cultivation of oilseed rape requires high amounts of pesticides, which has negative environmental impacts and leads to pesticide resistance. Legislation in the European Union has decreased the number of effective active substances so alternative plant protection strategies are in great demand. Biological control approaches offer exciting potential,″ said Dr Cook. 

Papers in the journal include studies showing the potential for control of CSFB by based on nematodes and pathogenic fungi, details of how new approaches to the taxonomy of disease-causing organisms are opening up novel avenues of control, and advances in surveillance technology such as using optical sensors to spot invading bugs. Improved understanding of the migration and ecology of insect pests is also providing promising insights for more targeted management strategies.

″We hope these lines of research can ultimately contribute to healthier and safer food products and a less polluted environment through reduced use of synthetic pesticides,″ said Dr Cook.

PUBLICATION

INTEGRATED PEST CONTROL IN OILSEED CROPS—NEW ADVANCES FROM THE RAPESEED RESEARC…