Grape Cultivar Feeding Preference of Adult Japanese Beetles

Abstract

<jats:p>The Japanese beetle is a major insect pest of grapes in the eastern United States. An examination of Japanese beetle preference for currently grown grape cultivars would be useful to growers in developing pest control strategies with reduced chemical inputs. The objective of this study was to examine grape cultivar preference of Japanese beetles for commercially available grape cultivars in both cage choice and field experiments. Outdoor cage choice screening studies included 32 grape cultivars from various <jats:italic>Vitis</jats:italic> species and were conducted at the Kentucky State University Research Farm in Frankfort, KY. Feeding preference was determined by examining incidence of damage (percent of leaves damaged per vine) and leaf area loss, which was rated as 0 pt, 0%; 1 pt, 1% to 10%; 2 pt, 11% to 20%; 3 pt, 21% to 30%; 4 pt, 31% to 40%; 5 pt, 41% to 50%; 6 pt, 51% to 60%; and 7 pt, more than 60%, by leaf position from the first (shoot tip) to 10th leaves. Analysis of variance indicated that there were significant differences in Japanese beetle leaf damage for cultivar and leaf position main effects. Leaf damage by Japanese beetles varied by leaf position on the shoot, with the fourth through sixth leaves from the tip with the most severe damage. Generally, cultivars showing an incidence of damage greater than 70% were either European or French hybrid cultivars, and those with less than 70% incidence of damage were either American cultivars or American cultivars with a <jats:italic>V. labrusca</jats:italic> background. The grape cultivars Marquis, Reliance, Catawba, Concord Seedless, Concord, Edelweiss, and Einset showed promise as selections for growers interested in reduced chemical inputs for control of Japanese beetles.</jats:p>

Impact of insecticide-manipulated defoliation by Japanese beetle (Popillia japonica) on grapevines from vineyard establishment through production

“…Tough leaves with low nitrogen and water content likely contribute to Concord's resistance to JB defoliation, as those characteristics are indicative of poor food quality for leaf‐chewing insects 15. Others, too, have suggested that leaf physical characteristics may determine JB preference among grape cultivars 5, 6. Although not statistically significant, non‐treated Concord vines outperformed sprayed vines in a number of parameters, suggesting that adverse effects (e.g.…”

“…JBs aggregate on grapevines in response to aromatic volatile compounds released from JB‐damaged leaves 4. They tend to feed most heavily on European and French–American hybrid varieties,5, 6 but the basis for such apparent preference has not been studied.…”

Blackberry Cultivar Feeding Preference of Adult Japanese Beetles

“…However, reports from other authors indicate that the Japanese beetle can exhibit different feeding incidence on different plant cultivars. For instance, Gu and Pomper (2008) found that feeding incidence by the Japanese beetle on 33 cultivars of grapes varied from 42% to 49.8 ± 13.6 a n.t. Prime-Jim 47.7 ± 9.6 a n.t.…”

“…In the field, the cultivars with a low feeding incidence attracted about five times fewer Japanese beetles than those with a high feeding incidence. The results of Gu and Pomper (2008) suggest that percentage of damaged leaves reflected the attractiveness of a given grape cultivar, and that if the beetles were attracted to a particular cultivar, they fed on it, and they did not explore more feeding opportunities. In our study, feeding incidence was similar in all the blackberry cultivars investigated, in both 2017 and 2018, suggesting that all the cultivars attracted Japanese beetles with the same moderate efficacy (Tables 1 and 2).…”

Arthropod Management in Vineyards:

“…An evaluation of JB preference for grape cultivars was carried out by Gu and Pomper ( 2008 ) . A point system was assigned based on the % of damaged leaves per vine, as well as of leaf area loss.…”