Color Preference of Harlequin Bug (Heteroptera: Pentatomidae).

Harlequin bug, Murgantia histrionica (Hahn), is an important pest of Brassica crops in the southern United States. Regional populations are highly variable and unpredictable from farm-to-farm, and therefore accurate monitoring of activity would greatly improve IPM decision-making and the timing of control tactics. To our knowledge, there is no monitoring device or proven trapping system for this pest. We contribute new knowledge of harlequin bug visual ecology, which will aid in the development of an effective trap. In both lab and field color choice experiments, harlequin bug adults and large nymphs responded positively to green and black colors, and statistically less frequently to yellow, white, purple, or red with the exception of adult females, which were most attracted to red and green in the lab, but green and black in the field. We conclude that future trapping devices for harlequin bug should be green or black in color.

Behavioral Response of the Brown Marmorated Stink Bug (Hemiptera: Pentatomidae) to Semiochemicals Deployed Inside and Outside Anthropogenic Structures During the Overwintering Period.

The brown marmorated stink bug, Halyomorpha halys (Stål), is an invasive species from Asia capable of causing severe agricultural damage. It can also be a nuisance pest when it enters and exits anthropogenic overwintering sites. In recent years, pheromone lures and traps for H. halys have been developed and used to monitor populations in field studies. To date, no study has investigated the applicability of these monitoring tools for use indoors by building residents during the overwintering period. Herein, we 1) assessed when in late winter (diapause) and spring (postdiapause) H. halys begins to respond to its pheromone (10,11-epoxy-1-bisabolen-3-ol), 2) evaluated whether pheromone-based tools can be used reliably for monitoring H. halys adults in unheated and heated buildings, and 3) elucidated the potential for indoor management using pheromone-baited traps. A 2-yr trapping study suggested that H. halys began to respond reliably to pheromone-baited traps after a critical photoperiod of 13.5 h in the spring. Captures before that point were not correlated with visual counts of bugs in buildings despite robust populations, suggesting currently available pheromone-baited traps were ineffective for surveillance of diapausing H. halys. Finally, because baited traps captured only 8-20% of the adult H. halys known to be present per location, they were not an effective indoor management tool for overwintering H. halys. Our study contributes important knowledge about the capacity of H. halys to perceive its pheromone during overwintering, and the ramifications thereof for building residents with nuisance problems.

Supercooling Points of Murgantia histrionica (Hemiptera: Pentatomidae) and Field Mortality in the Mid-Atlantic United States Following Lethal Low Temperatures.

The harlequin bug, Murgantia histrionica (Hahn), is a serious pest of brassicaceous vegetables in southern North America. While this insect is limited in its northern range of North America, presumably by severe cold winter temperatures, specific information on its cold hardiness remains unknown. We determined the supercooling points (SCPs) for Maryland and Virginia adult populations and found no significant difference among these populations. SCPs were similar for adults ([Formula: see text] = -10.35 °C; [Formula: see text] 2.54) and early and late instar ([Formula: see text] = -11.00 °C; [Formula: see text] 4.92) and between adult males and females. However, SCPs for first instars ([Formula: see text] = -21.56 °C; [Formula: see text]1.47) and eggs ([Formula: see text] = -23.24 °C; [Formula: see text]1.00) were significantly lower. We also evaluated field survival of overwintering harlequin bug adults during extreme cold episodes of January 2014 and January 2015, which produced widespread air temperatures lower than -15 °C and subfreezing soil temperatures in the Mid-Atlantic Region. After the 48-h episode in 2014, bug mortality in exposed field sites averaged 88%, compared to <5% mortality of bugs sheltered in an unheated greenhouse (recorded minimum temperature 4.4 °C). After the 2015 episode, ∼80% of adults that were established in the field the previous November and then sheltered in an unheated garage during the episode, died, in contrast to 96% mortality in exposed field sites. Our results provide new information on M. histrionica overwintering biology, and thermal limitations to its distribution, which leads to improved predictive capabilities to forecast pest severity.

Attractiveness of harlequin bug, Murgantia histrionica, aggregation pheromone: field response to isomers, ratios, and dose.

A two-component pheromone, (3S,6S,7R,10S)- and (3S,6S,7R,10R)-10,11-epoxy-1-bisabolen-3-ol (murgantiol), present in emissions from adult male harlequin bugs, Murgantia histrionica, is most attractive in field bioassays to adults and nymphs in the naturally occurring ratio of ca. 1.4:1. Each of the two individual synthetic stereoisomers is highly attractive to male and female adults and nymphs, but is more attractive in combination and when deployed with a harlequin bug host plant. Blends of 8 stereoisomers also are highly attractive, suggesting that isomers not found in the natural pheromone are not repellent. Deployment of an inexpensive non-stereospecific synthetic pheromone holds promise for efficient trapping and/or use in trap-crops for this important pest in North America.