Starker E. Wright

Identification of a new blend of apple volatiles attractive to the apple maggot: Rhagoletis pomonella

Solid-phase microextraction (SPME) and gas chromatography coupled with electroantennographic detection (GC-EAD) were used to identify a new blend of volatiles from apples as the key attractants for the apple maggot fly, Rhagoletis pomonella (Walsh). The new five-component blend contains butyl butanoate (10%), propyl hexanoate (4%), butyl hexanoate (37%), hexyl butanoate (44%), and pentyl hexanoate (5%) compared with a previously reported seven-component mix of hexyl acetate (35%), (E)-2-hexen-1-yl acetate (2%), butyl 2-methylbutanoate (8%), propyl hexanoate (12%), hexyl propanoate (5%), butyl hexanoate (28%), and hexyl butanoate (10%). Volatiles from five different varieties of apple elicited reproducible and high EAD responses from R. pomonella antennae to the same five chemicals. In flight-tunnel choice tests involving red sticky spheres with odor sources, the new five-component blend of apple volatiles showed significantly more activity than the previous seven-component blend or the single compound, butyl hexanoate. In a field trial captures with the new five-component blend were better than with butyl hexanoate, which is currently used with commercial apple maggot monitoring spheres.

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.

EVALUATION OF INDIVIDUAL COMPONENTS OF PLUM ODOR AS POTENTIAL ATTRACTANTS FOR ADULT PLUM CURCULIOS

We evaluated olfactory attraction of overwintered plum curculio (PC) adults, Conotrachelus nenuphar, to 16 individual volatile components of unripe plum odor in the laboratory using a still-air dual-choice bioassay system and in the field using baited cotton dental wicks attached to boll-weevil traps placed on the ground beneath the canopy of unsprayed apple trees. Two compounds, ethyl isovalerate and limonene, were significantly attractive in both laboratory bioassays and field experiments. In laboratory bioassays, as concentration was decreased across five orders of magnitude, a greater number of compounds elicited responses suggestive of attractancy (except at the lowest concentration). Even so, linalool, 2-hexanone, and 3-hydroxy-2-butanone were the only other compounds showing significant attractiveness in laboratory bioassays, but none of these (nor any other compounds) were significantly attractive in field assays. We suggest that the use of ethyl isovalerate and/or limonene as odor attractants offers potential to increase the efficacy of current traps for monitoring PCs immigrating into fruit orchards during spring.

Monitoring Plum Curculio, Conotrachelus nenuphar (Coleoptera: Curculionidae), Populations in Apple and Peach Orchards in the Mid-Atlantic

We evaluated responses of plum curculio, Conotrachelus nenuphar (Herbst), to four trap types in commercial and unsprayed apple and peach orchards. Trap types included black pyramid and clear Plexiglas panel traps deployed outside the orchard 2 m from the border row, and branch-mimicking cylinder and trunk-mounted screen traps attached to trees in the border row. Bait treatments evaluated in conjunction with each trap type included the synthetic fruit volatile benzaldehyde, the aggregation pheromone grandisoic acid (GA), benzaldehyde in combination with GA, and an unbaited control treatment. In commercial apple orchards, significantly more plum curculio were captured in traps baited with benzaldehyde + GA compared with traps baited with other treatments. Furthermore, significantly more plum curculio were captured by screen traps baited with benzaldehyde + GA compared with unbaited control traps. Significantly more plum curculio were captured by screen traps compared with other trap types in an unsprayed apple orchard. Very few captures were recorded in commercial peach orchards. Dissections of trapped females indicate that bivoltine populations are present in the mid-Atlantic. In general, correlations between timing and amount of trap captures and timing and amount of fruit injury inflicted concurrently or 1 wk after trap captures were very weak for all trap types and bait combinations. Our results agree with previous studies in the northeastern United States in which trap captures are increased by presence of semiochemical baits but fail to serve as reliable tools to determine need for and timing of insecticide application against plum curculio.

Arthropod pest and natural enemy abundance under second-level versus first-level integrated pest management practices in apple orchards: a 4-year study

Abstract The authors conceive of second-level integrated pest management (IPM) in apple orchards as involving integration of multiple management tactics across all classes of pests. From 1991–1994, a second-level IPM pilot project was carried out in six commercial Massachusetts apple orchard blocks (2–4 ha) in which pest and natural enemy populations and injuries to fruit were compared with those in adjacent blocks receiving first-level IPM practices (considered to be integration of tactics within a single class of pests). The approach to second-level IPM was use of chemically based tactics for arthropod, disease and weed control during the first part of the growing season (up to mid-June for arthropods) and thereafter use of only biologically based tactics (cultural, behavioral and biological control methods). This article deals with findings on arthropod management. As expected, total injury to fruit by insects causing damage before mid-June did not differ between second-level (4.7%) and first-level (4.8%) IPM blocks. Total injury to fruit by insects active after mid-June averaged about the same (0.5%) in both types of blocks in 1991 and 1992, but in 1993 and 1994 it averaged more in second-level blocks (4.8%) than first-level blocks (1.9%). This was particularly true for Grapholitha prunivora Walker and leafrollers and less so for Cydia pomonella (L.) and Rhagoletis pomonella (Walsh). Among foliar pest arthropods and their natural enemies, populations of aphids and aphid predators and populations of spider mites and mite predators averaged about the same in both types of blocks. Populations of leafminers averaged lower and parasitoids of leafminers averaged greater in second-level blocks. Populations of leafhoppers averaged greater in second-level blocks. Pesticide use against fruit-damaging insects averaged 37% less in second-level than in first-level blocks, but against foliar-damaging arthropods, it was not less. Some refinements of second-level IPM tactics for arthropod control are needed before second-level IPM practices can be recommended broadly to commercial growers in New England as an economical and reliable alternative to first-level IPM.

Attracticidal spheres for controlling apple maggot flies: commercial-orchard trials.

Wooden pesticide‐treated red spheres and biodegradable sugar/flour pesticide‐treated red spheres were compared with wooden sticky‐coated red spheres and insecticide sprays for controlling apple maggot flies, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), in small blocks of apple trees in Massachusetts commercial orchards in 1997, 1998 and 1999. Pesticide‐treated spheres received a coating of 70% latex paint, 20% feeding stimulant (sucrose), and 10% formulated insecticide (containing 20% imidacloprid). To replenish sucrose lost during rainfall, wooden spheres were capped with a disc comprised of hardened sucrose that seeped onto the sphere surface, whereas the surface of sugar/flour spheres received sucrose that seeped from the interior. Each year, each of the 24 perimeter trees of each non‐sprayed block received a sphere baited with butyl hexanoate (an attractive component of host fruit odor), with the intent of intercepting immigrating flies. Based on captures of flies on unbaited sticky‐coated red spheres placed near the center of each block and on periodic samples of fruit for injury, there was a consistent pattern of treatment performance. Each year, sticky‐coated spheres were only slightly less effective than two or three sprays of organophosphate insecticide, sugar/flour pesticide‐treated spheres were only slightly less effective than sticky spheres, and wooden pesticide‐treated spheres were least effective. Versions of pesticide‐treated spheres used in 1999 were more durable than those used in previous years, but further improvement is needed before either wooden or sugar/flour pesticide‐treated spheres can be recommended for grower use.

Impact of insecticide residue exposure on the invasive pest, Halyomorpha halys (Hemiptera: Pentatomidae): analysis of adult mobility.

ABSTRACT Twenty eight insecticides were evaluated in the laboratory to characterize the impact of specific compounds on locomotory behavior and mobility of adult Halyomorpha halys (Stål) (Hemiptera: Pentatomidae). Horizontal distance and angular velocity were measured for individuals exposed to dry insecticide residue for 4.5 h to evaluate how quickly and intensely a given insecticide induced changes in motor activities in no-choice glass arenas. Eight out of nine pyrethroid insecticides induced uncoordinated and irregular movement within 10 min after exposure to insecticides. After 1.5 h, most adults were incapacitated. By contrast, there was no immediate stimulation when H. halys were exposed to organophosphate residues. After 1.5 h, four out of seven organophosphates resulted in increased horizontal distance moved and angular velocity indicating irregular walking paths by exposed adults. Carbamate and neonicotinoid insecticides produced fairly similar patterns with virtually no stimulation in horizontal distance moved or angular velocity, except for imidacloprid and thiacloprid. Neither endosulfan (organochlorine) nor indoxacarb (oxadiazine) affected the horizontal movement of H. halys. Vertical distance climbed by adult H. halys was measured immediately after the 4.5-h insecticide exposure period and at 7 d. In general, adults that survived until day 7 were able to climb vertical distances similar to those in the control. In particular, this result was observed for seven out of nine pyrethroid materials that incapacitated all adults after the 4.5-h exposure period. Mobility changes of adult H. halys are discussed in the context of enhancing integrated pest management programs.

Response of plum curculio (Coleoptera: Curculionidae) to odor-baited traps near woods.

Abstract Response of overwintered plum curculios, Conotrachelus nenuphar (Herbst), to odor-baited traps was evaluated from the beginning until nearly the end of emigration from overwintering sites in woods. We evaluated clear sticky Plexiglas panels and black pyramid traps placed close to woods adjacent to apple trees in an unsprayed section of an orchard. Traps were baited with aggregation pheromone (grandisoic acid) alone or in combination with one of six synthetic fruit volatiles (benzaldehyde, decyl aldehyde, E-2-hexenal, ethyl isovalerate, hexyl acetate, or limonene). Unbaited traps served as a control treatment. Plum curculio emigration from woods was divided into early-, mid-, and late-season periods based primarily on phenological stage of apple bud and fruit development (tight cluster to bloom, petal fall, and fruit set, respectively). During both early- and late season, panel and pyramid traps baited with benzaldehyde plus pheromone were significantly more attractive than any other traps (baited or unbaited), except panel traps baited with ethyl isovalerate plus pheromone in early season, which likewise captured significantly more adults than unbaited panel traps. During midseason, no lures were significantly attractive, possibly due to prevailing cool weather, unfavorable for adult activity. Over the entire season, panel or pyramid traps baited with benzaldehyde plus pheromone captured nearly six times as many plum curculios as unbaited traps of each type, whereas traps baited with pheromone alone captured about twice as many as unbaited traps of each type. We provide information on sex ratio, female maturity stage, and mating status, and several weather parameters associated with trap captures. We conclude that panel or pyramid traps, or a combination, baited with benzaldehyde plus pheromone placed at borders of plum curculio overwintering sites can be a valuable tool for monitoring the beginning, peak, and end of adult immigration into apple orchards.

Compounds from Host Fruit Odor Attractive to Adult Plum Curculios (Coleoptera: Curculionidae)

Three release rates of each of 30 compounds identified as components of the odor of unripe host plum or apple fruit were evaluated in field tests in 1999 for attractiveness to adult plum curculios, Conotrachelus nenuphar (Herbst). Compounds were introduced into polyethylene vials and assayed in association with boll weevil traps placed beneath infested apple trees in Ohio and Massachusetts. Results confirmed previously reported attractiveness of limonene and ethyl isovalerate to this insect. In addition, at least six other compounds showed good evidence of attractiveness (benzaldehyde, benzyl alcohol, decanal, E-2-hexenal, geranyl propionate and hexyl acetate), and five other compounds appeared worthy of further evaluation for attractiveness (2-hexanol, 1-pentanol, 2-pentanol, phenylacetaldehyde and 2-propanol). Degree of attractiveness of compounds varied according to release rate.