Vine Weevil, Otiorhynchus sulcatus (Coleoptera: Curculionidae), Management: Current State and Future Perspectives

Vine weevil, also known as black vine weevil, Otiorhynchus sulcatus, has been one of the most economically important pest species of global horticultural crops for the past five decades. This period has seen many changes in crop protection practices, including wide-scale adoption of biological controls such as entomopathogenic nematodes and fungi in place of conventional synthetic insecticides. Despite the experimental efficacy of these controls, growers continue to report significant crop losses associated with vine weevil infestation. We argue that simply switching from synthetic insecticides to biological controls, rather than using these controls as part of an integrated management program, is a key factor in the continued importance of this pest. An improved understanding of vine weevil biology and ecology is at the center of the development of truly integrated pest management programs. To this end, we identify opportunities created through recent vine weevil research and highlight key knowledge gaps in which further research may contribute to improved future management approaches.

Relationship of Black Vine Weevil Egg Density and Damage to Two Cranberry Cultivars

Black vine weevil (BVW), Otiorhynchus sulcatus (Coleoptera: Curculionidae, Fabricius), is a serious pest of cranberry, Vaccinium macrocarpon Ait. Larvae feed undetected within the soil and cause damage to roots and underground vines. We correlated damage caused by feeding larvae from known BVW egg densities. Two cultivars of potted cranberry vines, ‘Stevens’ and ‘McFarlin’, were inoculated with 0, 5, 10, 20, 40, and 80 eggs per pot. Root damage and canopy health were assessed. ‘Stevens’ exceeded ‘McFarlin’ in dry shoot weight, total shoot length, total leaf area, and dry root weight before egg treatments. Damage to underground vines increased with increasing egg density and more damage was found in ‘Stevens’ than ‘McFarlin’ at the highest egg densities. In August, plant water use and total shoot length in ‘McFarlin’ were significantly greater in plants treated with 0–5 eggs per pot compared with plants treated with 40–80 eggs per pot. The effect on total shoot length was more pronounced in October. ‘Stevens’ showed no response to increasing BVW density for up to 24 weeks. Destructive measurements showed decreased root weight in ‘McFarlin’ but not ‘Stevens’. Both cultivars showed a similar decrease in dry shoot weight, total shoot length, and percent green leaf area with increasing BVW egg density. Root damage increased as BVW egg density increased and this damage resulted in reduced plant water use for ‘McFarlin’. Reduced shoot growth and leaf area was recorded for both cultivars, although these effects were more apparent in ‘McFarlin’ and at an earlier stage than in ‘Stevens’.