Brent D. Short

Impact of the Invasive Brown Marmorated Stink Bug, Halyomorpha halys (Stål), in Mid-Atlantic Tree Fruit Orchards in the United States: Case Studies of Commercial Management

Four commercial orchards in the mid-Atlantic region of the United States were surveyed weekly in 2010 and 2011 for the presence of brown marmorated stink bug and the injury caused to both apple and peaches. Among tested sampling techniques, pyramid traps baited with the aggregation pheromone of Plautia stali Scott, methyl-(2E,4E,6Z)-decatrienoate, yielded the most brown marmorated stink bug adults and nymphs, followed by visual observations. Brown marmorated stink bugs began to feed on apples and peaches soon after fruit set and continued to feed on fruit throughout the growing season. Injury to apple was relatively inconsequential until after mid-June, whereas feeding on peaches resulted in immediate economic injury as the surface became distorted, dented, discolored, and the flesh beneath turned brown. Significantly more apples were injured and with greater severity in 2010 than in 2011. Likewise, percent injury on the exterior portion of each apple plot was significantly greater than injury reported from the interior in both years. Growers increased the number of insecticide applications nearly 4-fold from 2010 to 2011. In addition to the increased number of targeted insecticide applications, growers also reduced the interval between treatments in 2011. A metric was created to compare the relative intensity of each growers commercial management program between seasons and amongst each other.

Development of Behaviorally-Based Monitoring Tools for the Brown Marmorated Stink Bug (Heteroptera: Pentatomidae) in Commercial Tree Fruit Orchards

Abstract Captures of the invasive brown marmorated stink bug, Halyomorpha halys (Stål), were significantly greater in pyramid traps baited with the known attractant, methyl (2E,4E,6Z)- decatrienoate, compared with unbaited traps. A dose-dependent response by adults to lures formulated with increasing amounts of methyl (2E,4E,6Z)-decatrienoate and deployed in association with black pyramid traps also was observed. Among pyramid traps representing different visual stimuli including black, green, yellow, clear, white and yellow, significantly greater captures were recorded in baited black pyramid traps for adults in 2009 and nymphs in 2010 compared with other trap types; the dark upright silhouette created by this trap likely represents a trunk-mimicking visual stimulus to foraging bugs. A ground-deployed baited black pyramid trap also captured significantly greater numbers of nymphs and adults compared with canopy-deployed commercially available baited traps from Japan. Based on semi-field cage studies, brown marmorated stink bug was confirmed to be bivoltine within the mid-Atlantic region. Thus, the need for a reliable monitoring tool to detect presence, abundance and seasonal activity of brown marmorated stink bug in tree fruit and other cropping systems is critical.

Efficacy of insecticide residues on adult Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) mortality and injury in apple and peach orchards.

BACKGROUND The primary threat from Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) originates from populations continuously dispersing from and among wild and cultivated hosts, so many individuals may not be directly sprayed with insecticides. Limited information exists regarding field-based residual activity of insecticides for management of H. halys in tree fruit. Thus, we conducted field-based bioassays in apple and peach orchards to evaluate residual activity of insecticides commonly applied against H. halys. Adults used in these trials were collected from wild and cultivated hosts less than one week prior to testing to more accurately reflect the susceptibility of wild H. halys populations in the field throughout the season. RESULTS Significantly higher mortality rates of Halyomorpha halys were observed early in the growing season, when overwintered adults were prevalent, compared with populations present later in the growing season that included new generation adults. Significantly higher mortality was recorded for adults exposed to fresh insecticide applications compared with three- and seven-day old residues. Typically, the addition of an adjuvant did not enhance efficacy or residual activity of insecticides. Significantly fewer injury sites were recorded on apples treated with dinotefuran and fenpropathrin compared with the untreated apples for all residue ages. CONCLUSIONS Overwintered Halyomorpha halys populations are easier to kill with insecticide applications than the first and second generation which are present in the field during the mid- to late-season. Residual activity of nearly all insecticides decreased significantly three days after application and adjuvants generally did not increase residual activity. These factors should be considered in developing season-long programs for management of this invasive species in tree fruit.

Attraction of the invasive halyomorpha halys (Hemiptera: Pentatomidae) to traps baited with semiochemical stimuli across the United States

ABSTRACT A recent identification of the two-component aggregation pheromone of the invasive stink bug species, Halyomorpha halys (Stål), in association with a synergist, has greatly improved the ability to accurately monitor the seasonal abundance and distribution of this destructive pest. We evaluated the attraction of H. halys to black pyramid traps baited with lures containing the pheromone alone, the synergist methyl (2E,4E,6Z)-decatrienoate (MDT) alone, and the two lures in combination. Traps were deployed around areas of agricultural production including fruit orchards, vegetables, ornamentals, or row crops in Delaware, Maryland, North Carolina, New Jersey, New York, Ohio, Oregon, Pennsylvania, Virginia, and West Virginia from mid-April to mid-October, 2012 and 2013. We confirmed that H. halys adults and nymphs are attracted to the aggregation pheromone season long, but that attraction is significantly increased with the addition of the synergist MDT. H. halys adults were detected in April with peak captures of overwintering adults in mid- to late May. The largest adult captures were late in the summer, typically in early September. Nymphal captures began in late May and continued season long. Total captures declined rapidly in autumn and ceased by mid-October. Captures were greatest at locations in the Eastern Inland region, followed by those in the Eastern Coastal Plain and Pacific Northwest. Importantly, regardless of location in the United States, all mobile life stages of H. halys consistently responded to the combination of H. halys aggregation pheromone and the synergist throughout the entire season, suggesting that these stimuli will be useful tools to monitor for H. halys in managed systems.

Impact of Organic Insecticides on the Survivorship and Mobility of Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) in the Laboratory

Abstract The invasive brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) has become a major concern for specialty and row crop growers in the United States. Management tactics against this new pest are currently limited to repeated synthetic insecticide applications, thereby making this problem even more challenging for the organic grower community. This study evaluated the insecticidal efficacy of organically-approved insecticides (azadirachtin, potassium salts of fatty acids, spinosad, pyrethrins, and pyrethrins + kaolin) and experimental biopesticides (Chromobacterium subtsugae Martin et al. strain PRAA4-1T [MBI-203], extract of Eucalyptus sp. [MBI-205], and Burkholderia sp. [MBI-206]). These materials were presented as 18-h old dried residues against adult H. halys in the laboratory. Nonlethal effect on horizontal walking mobility of H. halys was evaluated during a 4.5-h insecticide exposure period; vertical walking mobility was measured at 4.5 h and 7 d after the insecticide exposure. All treatments, except for azadirachtin, resulted in significantly higher mortality of H. halys over 7 d, compared with the untreated control. Pyrethrins + kaolin, MBI-203, and MBI-206 resulted in ≥80% of individuals moribund or dead after 7 d. Horizontal walking distance of H. halys was significantly greater immediately and 3 h after exposure to pyrethrins and MBI-203, respectively, compared with the untreated control. After the 4.5-h exposure to potassium salts, pyrethrins, and pyrethrins + kaolin, surviving H. halys climbed significantly shorter distances while those exposed to MBI-203 climbed significantly greater distances compared with the untreated control, in the vertical mobility bioassay. After 7 d, there was no measurable difference, in the vertical walking distance by surviving individuals, between any of the tested materials and the untreated control. The results of the study are discussed within the context of developing effective management strategies for H. halys in organic production systems.

Deltamethrin-Incorporated Nets as an Integrated Pest Management Tool for the Invasive Halyomorpha halys (Hemiptera: Pentatomidae)

Abstract Long-lasting insecticide nets (LLINs), which have insecticide incorporated within the fibers, have been widely used for control of malaria and other insect-vectored diseases. Only recently have researchers begun exploring their use for control of agricultural pests. In this study, we evaluated the toxicity of a deltamethrin-incorporated LLIN, ZeroFly (Vestergaard–Frandsen, Washington, DC) for control of the brown marmorated stink bug, Halyomorpha halys (Stål). In the lab, exposure to the ZeroFly net for 10 s resulted in >90% mortality of H. halys nymphs and >40% mortality of H. halys adults. Longer exposure to the net resulted in higher mortality. In another experiment, a 15-cm2 sheet of ZeroFly net placed inside of the stink bug trap provided long-lasting kill of H. halys adults equal to or better than standard dichlorvos kill strip. Potential for the use of ZeroFly nets for H. halys IPM is discussed.

Behavioral Responses of Drosophila suzukii (Diptera: Drosophilidae) to Visual Stimuli Under Laboratory, Semifield, and Field Conditions

Abstract Drosophila suzukii Matsumura (Diptera: Drosophilidae) is an invasive pest in North America and Europe that attacks soft-skinned ripening fruit such as raspberries, blackberries, and blueberries. Little is known regarding the specific cues D. suzukii utilizes to locate and select host fruit, and inconsistencies in trap performance indicate the need for the development of improved monitoring and management techniques for this insect. Our studies focused on identifying attractive visual cues for adult D. suzukii and incorporating these cues into a potential attract-and-kill tactic for D. suzukii management. We evaluated D. suzukii response to color, shape, and size-specific stimuli. For color, we evaluated 10.2-cm-diameter spheres painted black, red, purple, orange, green, yellow, blue, or white. Shape stimuli (254 cm3 surface area) included sphere, cube, pyramid, inverted pyramid, vertical or horizontal cylinder and were painted red. Size stimuli included red 2.5-, 10.2-, 15.2-, and 25.4-cm-diame-ter spheres. Trials were conducted under laboratory, semifield, and field conditions. For color, adults preferred black and red spheres to all other colors evaluated. Among shapes, there was no significant preference. For size, larger spheres captured significantly more D. suzukii compared with a small 2.5-cm-diameter sphere. Determining D. suzukii visual preference will aid in trapping and behaviorally based management programs.

Factors affecting appearance of stink bug (Hemiptera: Pentatomidae) injury on apple.

ABSTRACT Three main types of stink bug injury have been reported on the surface of apple fruit: (1) discolored dots, (2) discolored dots with depressions, and (3) discolored dots with discolored depressions. From 2005 to 2008, studies were performed to determine the factors linked to the variations in the appearance of adult stink bug injury on apple fruit observed at harvest. The main factors tested were type of feeding injury (i.e., mechanical versus breakdown and removal of tissues), time between injury and evaluation, cultivar, fruit maturity, and relative exposure to sunlight and UV radiation. No differences were observed that were caused by type of feeding. Studies of the time between injury and evaluation showed that there is a progression in the development of injury appearance. This progression of injury is influenced by cultivar and relative maturity of the fruit. Concomitantly, sites of injury on fruit exposed to no or limited sunlight and UV radiation were less likely to progress to discolored depressions.

Diagnosis and Variation in Appearance of Brown Stink Bug (Hemiptera: Pentatomidae) Injury on Apple'

Adult brown stink bugs, Euschistus se,-vus (Say), were caged individually on limbs with apple fruit of 6 cultivars in research orchards in West Virginia. Studies were performed to describe specific characteristics of damage that could be used for field and/or laboratory diagno- sis of stink bug injury to apple fruit at harvest. These characteristics were separated into surface and subsurface features. On the apple surface, 3 prevailing types of stink bug injury were ob- served in the field: (1) a discolored dot, i.e., stink bug feeding puncture; (2) a discolored dot with a depression in the fruit; and (3) a discolored dot with a discolored depression in the fruit. Sub- surface characters were related to the extent of damage observed on the fruit skin. Common subsurface damage ranged from a stylet sheath to corky tissue of variable color, shape, and size that sometimes was not contiguous with the skin. Laboratory evaluations under a dissecting microscope revealed that the size of the stink bug feeding puncture was ...0.17 mm diam. This character was the only consistent, definitive symptom of stink bug injury present among all ob- served damage. Due to variability in other surface and subsurface characters, and potential problems with visual apparency of injury in the field, evaluations of suspected stink bug damage should be performed with 40X magnification in the laboratory to confirm the presence of stink bug feeding punctures.

Development of an Attract-and-Kill Strategy for Drosophila suzukii (Diptera: Drosophilidae): Evaluation of Attracticidal Spheres Under Laboratory and Field Conditions

Abstract Drosophila suzukii Matsumura (Diptera: Drosophilidae) is an invasive, polyphagous fruit fly that attacks soft-skinned fruits. Originally from Asia, D. suzukii has successfully invaded the United States and the European and South American countries. At present, calendar-based insecticide applications are used to combat D. suzukii. Here, we evaluate a behaviorally based attract-and-kill management technique using attracticidal spheres to reduce D. suzukii infestations in raspberries. In laboratory bioassays aimed at identifying effective toxicants, attracticidal spheres containing dinotefuran at 1.0% a.i. killed 100% of D. suzukii within 5 min. Spinetoram, spinosad, permethrin, lambda-cyhalothrin (CS) and lambda-cyhalothrin (WG), all at 1.0% a.i., killed 100% of D. suzukii within 24 h. In field trials, statistically equivalent infestation rates were recorded in raspberry plots protected by attracticidal spheres containing 1.0% a.i. spinetoram compared with standard weekly insecticide applications. In field trials using 1.0% a.i. dinotefuran, attracticidal spheres decreased D. suzukii infestations compared with control plots, but insecticide applications were more effective at reducing D. suzukii infestations, although differences in harvesting practices likely affected fly population densities and infestation rates in both years. Attracticidal spheres effectively attract and kill D. suzukii and reduce infestations rates under field conditions, indicating that this behavioral strategy holds promise in D. suzukii management.