They also have the potential to be an important predator of aphids, sawfly and midge in blackcurrant crops. Both the projects oulined below have produced key findings into the role of earwigs.
The work set out to understand the impact of applying crop-protection products in blackcurrants and examine how to integrate such products into pest-management programmes without causing harm to earwig populations in apple and pear crops.
In the blackcurrant project (SF168), the results appeared to show that plantations with higher toxicity scores from spray programmes had fewer earwig numbers, but there was no significant correlation. Earwig numbers varied between plantations where spray programmes were similar, suggesting other abiotic and biotic factors may have influenced earwig abundance, so further research is needed. However, research from TF 220 in orchards has shown that earwig populations can be affected by routine crop-protection programmes.
To protect earwigs in orchards, growers are advised to avoid early-summer applications of Envidor and Agrimec because young earwigs appear to decline in trees treated at this time. Building up earwig populations in orchards by selectively using crop-protection products will increase the natural control of many major pests and allow occasional sprays of more harmful products if needed. Results also suggest that an occasional application of Gazelle or Calypso is unlikely to have long-term effects on populations.