Cherry damage and the spatial distribution of European earwigs, (Forficula auricularia L.) in sweet cherry trees

Abstract

BACKGROUND: The European earwig, Forficula auricularia is an invasive insect pest found in many temperate regions of the world. Despite being well known predators, earwigs are considered pests in sweet cherry though this has never been empirically tested. Our aim was to quantify the relationship between damaged cherry fruit and earwig population size, cherry bunch size and earwig distribution in cherry tree canopies in the cherry varieties Ron's Seedling, Lewis, Sweet Georgia, and Lapin. RESULTS: Significant differences in earwig damage type and frequency were observed between varieties with earwig exclusion significantly reducing damage by 21% in Lapin and 34% in Ron's Seedling. Earwigs were strongly aggregated within cherry bunches, with greater numbers and damage observed in larger bunch sizes in all varieties except Ron's Seedling where stem damage was independent of bunch size. In Ron's Seedling, cherry stems were 40× more likely to be damaged than Lewis stems and Lewis fruit two times more likely to be damaged than Ron's Seedling fruit. Sweet Georgia fruit were 4.5 times and stems five times more likely to be damaged than in Lapin. No predictive relationship between cherry damage levels and earwig numbers either within the tree canopies or within monitoring traps could be determined. CONCLUSION: European earwigs may have a significant economic impact to sweet cherry production. The nature of this impact differs between cherry varieties and severity is strongly influenced by factors including bunch size. However, why damage differs between varieties remains unknown and warrants further investigation if the impact of earwigs to sweet cherry production is to be minimized.

Turning a Pest into a Natural Enemy: Removing Earwigs from Stone Fruit and Releasing Them in Pome Fruit Enhances Pest Control

“…However, to our knowledge, no field trials have investigated mass trapping as a pest control tactic for earwigs. Instead, previous research has demonstrated that excluding earwigs from the canopy using adhesive barriers can reduce earwig abundance in the canopy and decrease damage to apricots [42] and cherries [30]. In our study, the mass removal of earwigs using corrugated cardboard traps was not consistently successful in reducing fruit damage for either crop.…”

“…Although reports of earwigs damaging apples exist, this is likely caused by opportunistically using previous existing damage (e.g., stem bowl split, birds, hail), which would have resulted in a culled fruit, regardless of the expansion of damage by secondary earwig feeding [9,10]. However, earwigs are considered a minor pest of stone fruit (e.g., cherries, apricots, plums) because they can perforate the fruits' soft flesh [8,9,30], causing, for example, damage of up to 40% in apricots [31]. Because many orchard operations in the PNW grow both pome fruit and stone fruit, this presents a unique opportunity.…”

Predation on Drosophila suzukii within Hedges in the Agricultural Landscape

“…Due to their broad prey range, the identified predators might however be less suited for targeted biological control attempts compared to more specialist parasitoid species from D. suzukii ’s native range or even from invaded regions [ 44 ]. Furthermore, high densities of some predators like the omnivorous earwigs can also inflict damage to thin-skinned fruits such as cherries or grapes [ 45 , 46 , 47 ]. Nonetheless, these generalist predators might provide a non-negligible background regulation of D. suzukii and their presence in hedgerows in the agricultural landscape may contribute to the regulation of pest populations [ 33 , 48 ].…”

The dual role of earwigs (Dermaptera) in winter grain crops in Australia

“…The role of earwigs in agricultural systems is complex and influenced by a number of abiotic and biotic factors (Bassal et al., 2001; Boukary et al., 1997; Dib et al., 2017; Quarrell et al., 2021; Romeu‐Dalmau, Piñol, & Espadaler, 2012; Saladini et al., 2016; Tourneur & Meunier, 2019). Our trials suggest that of the three dominant earwig species found in grain crops in Australia, only F. auricularia causes notable damage to winter crop seedlings, while N. lividipes and L. truncata appear to have beneficial value and unlikely to cause economic damage to canola plants.…”

“…The most widespread species in grain crops within Australia is the European earwig ( Forficula auricularia Linnaeus) (Hill et al., 2019), which was introduced over a century ago (Quarrell et al., 2018). Forficula auricularia is omnivorous, consuming a variety of foods (plants, invertebrates, fungus, detritus) (Crumb et al., 1941), and has been observed as an irregular pest of grain crops (Murray et al., 2013) and stone fruit orchards (Bower, 1992; Quarrell et al., 2021). Of all Australian grown grains, canola ( Brassica napus ) suffers the greatest economic damage from F. auricularia , with estimates of approximately $4 to $8 million AUD in losses per annum depending on control measures used (Murray et al., 2013).…”