Author(s)

G. J. Pickering, E. J. Glemser, R. Hallett, D. Inglis, W. McFadden-Smith & K. Ker

Abstract

Coccinellidae (‘ladybeetles’) are generally known as beneficial insects. Many are voracious predators feeding upon harmful pests such as aphids, scale insects, mealy bugs and mites. Coccinellidae species have been introduced into many regions around the world as bio-control agents for a range of grains, fruit and other crops. However, in part because of a northerly migration due to global warming, introduced species are now displacing native Coccinellidae species in some areas, and reaching densities that pose significant challenges for the grape and wine industries. Harmonia axyridis and Coccinella septempunctata are increasingly found in vineyards, and when they are inadvertently incorporated with grapes at harvest they produce a very potent odorant that taints the subsequent wine (‘ladybug taint’). This has significantly devalued grapes and wine from many regions over the last decade, and the beetles responsible now represent one of the greatest threats to the industry. Approaches for dealing with this novel pest have focused on repellency or exclusion of the beetle from the fruit or vineyard, and on remediation of juice and wine affected by ladybug taint. To date, the use of insecticidal sprays in the vineyard – including the synthetic pyrethroid, cypermethrin, and the organophosphate, malathion – has been the treatment of choice, but their use raises issues related to residues, phytotoxicity and wine quality. We present data from our labs on two alternative options. The first involves the use of potassium metabisulphite – commonly used in wine as an antimicrobial and antioxidant. Y-tube olfactometry and field studies show significant repellency effects (up to 50%) on Coccinellidae. In the second study, a range of grape-derived non-toxic compounds were assessed for their potential

Keywords

Coccinellidae, invasive species, ladybug taint, pesticide, sustainability, adaptation, grape, wine