Evaluation of compounds for repellency of the multicoloured Asian lady beetle (Coleoptera: Coccinellidae) in vineyards

Abstract

The multicoloured Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), has become a pest in North American vineyards during harvest due to its adverse effects on wine quality. This study evaluated alternative products that may be suitable for use in vineyards as repellents to the beetle. Products were screened as repellent for multicoloured Asian lady beetle in short-term laboratory trials. Thirteen products significantly reduced the number of beetles on grapes, Vitis vinifera (Vitaceae). Products that showed a 50% or greater repellency were evaluated for residual repellency 24, 48, and 72 hours after application. In these trials, pine oil was highly repellent at each testing period, whereas the repellency of most other products decreased over time. Eight repellent compounds were evaluated in field trials in commercial vineyards that had high multicoloured Asian lady beetle populations. The number of beetles on vines was counted 2–6 and 24–28 hours after application. In the field, the most effective repellents overall were Biobenton and Buran, which reduced the number of multicoloured Asian lady beetles by 39 and 34%, respectively. The discovery of new repellents of multicoloured Asian lady beetle provides an opportunity to improve management of the pest in vineyards and to reduce risk of wine taint without using broad-spectrum insecticides.

A Review of Ladybug Taint in Wine: Origins, Prevention, and Remediation

“…Coccinellidae beetles tend to appear in vineyards in the fall, after undertaking dispersal flights from their original feeding habitats both in response to temperature changes and as a result of the crops that initially hosted them being harvested [ 38 ]. Once in the vineyard, they do not damage healthy fruit, but they do feed on previously damaged grapes [ 39 ].…”

“…The authors found that when sprayed in the vineyard, KMS significantly reduced the number of MALB beetles on grape vines (≈30% fewer with a 5 g/L solution, and 50–60% fewer on vines treated with 10 g/L KMS). However, a later study showed no repellant effects in the field for a 10 g/L KMS solution, with the authors suggesting that stronger winds around the application date may have dissipated the SO 2 from the treated vines [ 38 ]. Encouragingly, KMS (5 g/L solution) sprayed in the vineyards at 14, 7, 3, or 1 day before harvest did not affect free SO 2 concentrations in the resultant grape juice [ 40 ].…”

“…A more recent report from Glemser et al [ 38 ] examined a series of products that were either already registered for use on grapes or had been previously reported as repellant to other insects. In lab-based repellency trials, carvacrol (a monoterpenoid found in essential oils), Timorex Gold (tea tree oil), pine oil, and granite dust were effective at reducing the number of MALB beetles by more than 80%, with pine oil being the most effective, even 72 h after application.…”

Prevalence and Management of Alkyl-Methoxypyrazines in a Changing Climate: Viticultural and Oenological Considerations

“…As H. axyridis is capable of contributing MPs and tainting wine up to three days after death [82], winegrowers need to be careful that dead beetles are not also harvested with the fruit at vintage. Indeed, Glemser et al [110] have reported dead beetles stuck within clusters between grapes after some spray applications.…”

“…The application of sulfur dioxide (SO 2 )-a ubiquitous compound used in winemaking-to vines looks very promising as a repellant, with a reduction in beetle density of 50-60% reported at a spray rate of 10 g/L potassium metabisulfite (KMS; [107]). However, it is important-as with a good spraying practice in general-that the SO 2 is not applied under strong wind conditions, as this may adversely affect its efficacy [110]. Additionally, bentonite (Biobenton)-and garlic powder + KMS-(Buran)-based products have also demonstrated efficacy as vineyard sprays, reducing the density of H. axyridis beetles by 39 and 34%, respectively [110].…”