Catch me if you can: the influence of refuge / trap design, previous feeding experience, and semiochemical lures on vine weevil (Coleoptera: Curculionidae) monitoring success

Abstract

BACKGROUND: Vine weevil, Otiorhynchus sulcatus F. (Coleoptera: Curculionidae), is one of the most economically important pest species of berry and ornamental crops globally. Monitoring this nocturnal pest can be difficult and time consuming and the efficacy of current tools is uncertain. Without effective monitoring tools, implementation of integrated pest management strategies is challenging. This study tests the relative efficacy of a range of vine weevil monitoring tools. Whether host-plant volatiles and weevil feeding experience influence vine weevil capture is also tested.RESULTS: Monitoring tool efficacy differed overall between the six monitoring tool designs tested and ranged from catches of 0.4% to 26.7% under semi-field conditions. Previous feeding experience influenced vine weevil behavior. In yew conditioned populations, 39% of the weevils responded to and were retained in the trap baited with yew foliage while 37% of weevils from Euonymus fortunei conditioned populations responded to and were retained in the trap baited with E. forunei foliage. A simple synthetic lure consisting of (Z)-2-pentenol + methyl eugenol also increased vine weevil catches compared with an unbaited trap. CONCLUSION: Demonstrating differences in the efficacy of different monitoring tool designs is an important first step for developing improved methods for monitoring vine weevil populations within crops. This study presents the first direct comparison of vine weevil monitoring tool designs and indicates that trap efficacy can be improved by baiting with host-plant material or a synthetic lure based on host-plant volatiles.

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

“…Although undoubtedly important, there are other factors beyond shape and size that influence monitoring tool efficacy. For example, Roberts et al [35] found that despite the general design (colour and silhouette) of vine weevil and red palm weevil traps being similar, their efficacy differed due to other characteristics including the entrance position. Our results demonstrated that vine weevil prefer to enter refuges with openings at their base over those with entrances at the top or in the middle.…”

“…Currently available vine weevil monitoring tools have variable efficacy and do not reliably indicate pest presence or density under field conditions [34]. A better understanding of vine weevil visual ecology and how they interact with monitoring tools will help inform their optimisation and improve detection and monitoring of this pest [35]. Trap location, size and surface texture are reported to influence weevil monitoring efforts [49,74,75].…”

“…Larvae were maintained on strawberry (Fragaria × ananassa cv Elsanta) or primrose (Primula vulgaris) plants housed within a controlled environment room (20 °C; 60% relative humidity; 16:8 photoperiod) (Fitotron, Weiss Technik, Ebbw Vale, Wales, UK). Larvae that completed their development were maintained as adults under the previously stated environmental conditions using a standard method of placing the weevils in plastic terrariums (30 × 19.3 × 20.6 cm) containing yew (Taxus baccata) branches and moist paper towels that were replaced weekly [23,25,35]. All adult weevils used in the following experiments were at least one month old and had been confirmed to be reproductively active.…”

“…Different monitoring tool designs have been used to detect the presence of vine weevil populations, including grooved wooden boards placed on the ground [29,31], pitfall traps [32], corrugated cardboard or ruffled material wrapped around plants [33,34] and commercially available crawling insect traps [25], including one designed specifically for vine weevil [35]. Despite extensive work to develop vine weevil monitoring tools, their efficacy is variable and often cannot be used to confidently monitor vine weevil populations in crops [35]. This lack of sensitivity and reliability reflects, in part, our limited understanding of the vine weevil adult visual ecology.…”

Integration of Entomopathogenic Fungi into IPM Programs: Studies Involving Weevils (Coleoptera: Curculionoidea) Affecting Horticultural Crops

“…Baits or attractants are not essential in Roguard refuges for O. sulcatus control since adults of this weevil are nocturnal and move inside the station during the day to avoid exposure to sunlight [ 64 ]. The recent development of lures ((Z)-2-pentenol + methyl eugenol) for O. sulcatus [ 259 ] has, however, improved the attractiveness of the refuges, and deploying the lures with an EPF formulated in linseed oil within the refuges has provided very effective control of O. sulcatus in the field [ 260 ].…”