Biological control of sentinel egg masses of the exotic invasive stink bug Halyomorpha halys (Stål) in Mid-Atlantic USA ornamental landscapes

Abstract

Biological invasions have far reaching effects on native plant and arthropod communities. This study evaluated the effect of natural enemies on eggs of the exotic invasive brown marmorated stink bug Halyomorpha halys (Stål) in experimental plots comprising species pairs of 16 ornamental trees and shrub genera from either Eurasia or North America and in wooded areas adjacent to the plots. Sentinel egg masses were placed on leaves of Acer, Cercis, Hydrangea, and Prunus in the plots and in seven genera of trees and shrubs in adjacent woods. Overall, rates of parasitism and predation in experimental plots were low, accounting for only 3.6 % and 4.5% of egg mortality, respectively. There were no significant differences in parasitism and predation rates between native or exotic plots or between plants of different genera. In 2015, predation was significantly higher in the experimental plots than in the wooded sites, but parasitism was significantly higher in the wooded sites. In the experimental plots, seven native and one exotic parasitoid species attacked sentinel egg masses. Six native parasitoid species attacked sentinel egg masses in the wooded sites. Parasitoids in the genus Trissolcus were more likely to attack egg masses in exotic plots than in native plots. There is no evidence that native natural enemies attacking eggs of the exotic BMSB were more prevalent in landscapes with native ornamental trees and shrubs than those with exotic trees and shrubs.

Surveying native egg parasitoids and predators of the invasive Halyomorpha halys in Northern Italy

“…When comparing the activity of parasitoids within the three years of the study, patterns were similar in 2014 and 2015, but in 2016 it was slightly delayed for unknown reasons. Overall predation was low generally low in spring, but progressively increased from May onwards in agreement with Cornelius et al ().…”

“…Similarly, surveys performed in invaded areas in the United States showed that Anastatus spp. were the most efficient endemic parasitoids attacking sentinel H. halys egg masses (Cornelius et al, ; Dieckhoff et al, ; Haye, Fischer, et al, ; Jones et al, ). In addition, Anastatus sp.…”

“…However, the impact of natural enemies could be underestimated because in response to the outbreak of H. halys population in 2015, the use of broad‐spectrum insecticides in this region has increased significantly (Maistrello et al, ), likely negatively affecting the natural enemy community and abundance in the fruit orchards. In the United States, predation on sentinel egg masses was similarly low, ranging from 4% to 11% (Cornelius et al, ; Jones et al, ; Ogburn et al, ). In these surveys, tettigonids and carabids were identified as the most efficient predators of H. halys eggs (Morrison et al, ).…”

Biological control effects of non‐reproductive host mortality caused by insect parasitoids

“…These laboratory results were later supported by (1) field observations of native parasitoids frequently attending sentinel H. halys egg masses in the field (indicating attack) with low associated offspring emergence levels (Cornelius et al. , b); (2) some species of native parasitoids emerging from sentinel egg masses that had been freeze‐killed before placement in the field (and thus lost their resistance to parasitoid development through an as‐yet unknown mechanism); and (3) high rates of H. halys egg abortion in sentinel egg masses placed in the field, some of which was directly attributable to unsuccessful parasitoid development (as determined by dissection), as well as a large amount of unassigned egg mortality that could possibly represent undetected additional parasitoid‐induced abortion (Cornelius et al. , b).…”

“…, b); (2) some species of native parasitoids emerging from sentinel egg masses that had been freeze‐killed before placement in the field (and thus lost their resistance to parasitoid development through an as‐yet unknown mechanism); and (3) high rates of H. halys egg abortion in sentinel egg masses placed in the field, some of which was directly attributable to unsuccessful parasitoid development (as determined by dissection), as well as a large amount of unassigned egg mortality that could possibly represent undetected additional parasitoid‐induced abortion (Cornelius et al. , b). A previous study has predicted an indirect benefit to native stink bugs (some of which could become pests if their density increases) resulting from unsuccessful attack of H. halys by native parasitoids (Abram et al.…”