RT Journal Article
SR Electronic
T1 Sensory-Based Action Threshold for Multicolored Asian Lady Beetle-Related Taint in Winegrapes
JF American Journal of Enology and Viticulture
JO Am J Enol Vitic.
FD American Society for Enology and Viticulture
SP 518
OP 522
DO 10.5344/ajev.2007.58.4.518
VO 58
IS 4
A1 Tederson L. Galvan
A1 Eric C. Burkness
A1 Zata Vickers
A1 Peter Stenberg
A1 Anna K. Mansfield
A1 William D. Hutchison
YR 2007
UL http://www.ajevonline.org/content/58/4/518.abstract
AB Action thresholds were developed for the Frontenac winegrape to aid growers in the management of the multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae). Sensory thresholds were determined for the H. axyridis-related taint in winegrapes by artificial infestation of H. axyridis-free grapes with live adult beetles. In a series of three-alternative forced choice (3-AFC) tests, a tasting panel compared control wine prepared with H. axyridis-free grapes and wine produced with increasing insect levels. Logistic regression was used to relate the number of H. axyridis per kg of grapes to the proportion of correct 3-AFC tests. With the same logistic regression model, the probability of correct answers was estimated using the logit probability function. The same logistic model was also used to estimate the infestation level for a given probability of correct answers. The estimated threshold at which 10% of the population could detect the characteristic off-flavor of H. axyridis was 1.9 beetle/kg grape, or 0.27 beetle/grape cluster of Frontenac. The sensory thresholds presented here can be interpreted as action thresholds for H. axyridis in winegrapes (i.e., number of H. axyridis per kg of grapes). These new action thresholds add information in the management of the H. axyridis in grapes, which when combined with existing control methods and sampling plans, form the basis of integrated pest management for this insect in winegrapes.