Optimising Vine Weevil, Otiorhynchus sulcatus F. (Coleoptera: Curculionidae), Monitoring Tool Design

Abstract

Vine weevil, Otiorhynchus sulcatus F. (Coleoptera: Curculionidae), is an economically important insect pest of horticultural crops. To identify an effective and reliable monitoring system for adult vine weevil, this study investigated the influence of colour, height and entrance position on the efficacy of a model monitoring tool using modified paper cups as refuges. Vine weevil preferences were determined by the number of individuals recorded within a refuge. When provided with a binary choice between black or white refuges, vine weevil adults showed a preference for black refuges. Vine weevils provided with a range of coloured refuges (blue, green, red and yellow) in addition to black and white refuges showed a preference for black and blue over the other colours and white refuges in group choice experiments. Refuge height and entrance position also influenced vine weevil behaviour with individuals exhibiting a preference for taller refuges and those with entrance openings around the refuge base. These results provide insights into refuge selection by adult vine weevils, which can be exploited to improve monitoring tool design. The importance of developing an effective monitoring tool for vine weevil adults as part of an integrated pest management programme is discussed.

Decoding attraction: Improving vine weevil monitoring by exploiting key sensory cues

“…For vine weevil, laboratory bioassays have demonstrated that small groups of vine weevil adults preferred dark monitoring tools over white or light-coloured ones. 4 To further explore monitoring tool colour preference and confirm whether black monitoring tools may be used as an effective method to detect this species, this study investigated the efficacy of black monitoring tools under glasshouse conditions. Our results confirm that black monitoring tools are more effective than white ones under field representative environmental conditions.…”

“…Vine weevil, Otiorhynchus sulcatus Fabricius (Coleoptera: Curculionidae), remains one of the most important pests of horticultural and ornamental crops globally. 4,5 This is largely due to the fact that monitoring is challenging as the larvae feed below ground while the adults are nocturnal, therefore controls are often applied too late to prevent economically significant losses. 5 The importance of correctly timing control applications has increased as vine weevil management has shifted from a reliance on persistent broad-spectrum insecticides to entomopathogenic nematodes (EPNs) and fungi (EPFs) used to target vine weevil larvae.…”

“…6,7 Indeed, despite widespread use of such controls, growers continue to report significant crop losses associated with vine weevil infestation and it is likely that this is in part due to the application of controls being incorrectly timed without use of reliable pest monitoring. 5 Use of monitoring tools for vine weevil adults is not considered reliable, largely due to gaps in knowledge of the biology and ecology of this species 4 as well as the unreliability of commercially available monitoring tools. 5 Visual appearance is important in the design of effective monitoring tools for many insect pests.…”

“…11 Similarly, vine weevil adults have a preference for black as well as darker coloured rather than white or lighter coloured monitoring tools. 4 Other visual cues used by insects for orientation include size and shape. 12,13 As a result, monitoring tool size, shape and entrance number/location have been suggested to be key factors in determining the efficacy of monitoring tools.…”

“…11 For vine weevil, while diameter has not previously been investigated, monitoring tool height and entrance position have been shown to be important for vine weevil monitoring design. 4 Monitoring tool position and density in relation to plants found in the same environment may also influence the number of individuals interacting with it. 15 The addition of olfactory cues such as pheromones and/or host plant volatiles has been shown to improve the efficacy of monitoring tools for Curculionidae pest species.…”