[show abstract][hide abstract] ABSTRACT: Since its initial discovery in Allentown, PA, USA, the brown marmorated stink bug (BMSB), Halyomorpha halys (Heteroptera: Pentatomidae) has now officially has been detected in 38 states and the District of Columbia in the USA. Isolated populations also exist in Switzerland and Canada. This Asian species quickly became a major nuisance pest in the mid-Atlantic USA region due to its overwintering behavior of entering structures. BMSB has an extremely wide host range in both its native home and invaded countries where it feeds on numerous tree fruits, vegetables, field crops, ornamental plants, and native vegetation. In 2010, populations exploded causing severe crop losses to apples, peaches, sweet corn, peppers, tomatoes and row crops such as field corn and soybeans in several mid-Atlantic states. Damaging populations were detected in vineyards, small fruit and ornamentals. Researchers are collaborating to develop management solutions that will complement current integrated pest management programs. This article summarizes the current pest status and strategies being developed to manage BMSB in the USA.
Outlooks on Pest Management 10/2012; 23(5):218-226.
[show abstract][hide abstract] ABSTRACT: douglas inkley 13 , kim a. hoelmer 14 , doo-hyung Lee 2 , and starker e. wright 2. Abstract Since its initial discovery in Allentown, PA, USA, the brown marmorated stink bug (BMSB), Halyomorpha halys (Heterop-tera: Pentatomidae) has now officially has been detected in 38 states and the District of Columbia in the USA. Isolated popu-lations also exist in Switzerland and Canada. This Asian species quickly became a major nuisance pest in the mid-Atlantic USA region due to its overwintering behavior of entering structures. BMSB has an extremely wide host range in both its native home and invaded countries where it feeds on numerous tree fruits, vegetables, field crops, ornamental plants, and native vegetation. In 2010, populations exploded causing severe crop losses to apples, peaches, sweet corn, peppers, tomatoes and row crops such as field corn and soybeans in several mid-Atlantic states. Damaging populations were detected in vine-yards, small fruit and ornamentals. Researchers are collabo-rating to develop management solutions that will complement current integrated pest management programs. This article summarizes the current pest status and strategies being devel-oped to manage BMSB in the USA.
[show abstract][hide abstract] ABSTRACT: Conservation biological control tactics, such as beetle banks, that increase habitat complexity generally increase epigeal predator abundance. Habitat complexity also increases alternative food which can attract and sustain predators but may reduce predation of target pests. Our goal was to determine how alternative food from different trophic levels (fly pupae and seeds) affects behavior and biological control efficacy of omnivorous carabid beetles. Seed subsidies increased omnivorous carabid abundance more than pupae by increasing aggregation and reducing emigration. Laboratory experiment demonstrated that both omnivorous carabid species preferred seeds and pupae over cutworms. However, in field cages seeds but not pupae resulted in greater cutworm damage to corn seedlings. Our results indicate that omnivorous carabids have a stronger behavioral response to seeds than prey such that only seeds influence aggregation, emigration, and crop damage. Interestingly, whereas seeds increased omnivorous carabid abundance, pupae had no affect on carnivore abundance. Thus, carabid guild composition is skewed in favor of omnivores when seed density increases. An important finding was that the effect of seeds on behavior, predation, and crop damage was consistent among replicate carabid species suggesting our results pertain to other omnivorous species in resource diverse habitats.Our results provide insight into the mechanisms underlying the unpredictable benefit of conservation biological control tactics that alter habitat complexity.
Biological Control - BIOL CONTROL. 01/2011; 57(3):229-235.
[show abstract][hide abstract] ABSTRACT: 1. Predator and alternative food density are important factors influencing herbivore suppression by generalist predators. Herbivore suppression can be reduced if predators forage preferentially on alternative foods. Cannibalism can increase at high predator densities, further reducing herbivore suppression. However, complex interactions are possible, as alternative food can increase predator abundance and survival restoring top-down effects on herbivores.2. In two species of carabid larvae (Poecilus chalcites and Anisodactylus ovularis), we studied how alternative foods (fly pupae and grass seeds) and predator density affect predation of black cutworm larvae and how alternative foods affect cannibalism among carabid larvae.3. Adding alternative food to microcosms generally reduced total predation of cutworms. However, the strength of this effect was dependent on carabid species, larval density, and food type.4. Increasing larval density from one to three per microcosm reduced per-capita predation by both species irrespective of alternative food treatment.5. Alternative food reduced cannibalism in both carabid species and increased survival of carabid larvae in field plots, such that twice as many were captured in plots subsidised with pupae than plots with no alternative food.6. These results provide new insight into the complex interactions that influence predator survival and herbivore suppression in resource diverse habitats by demonstrating the primacy of intraguild interactions among carabid larvae.
[show abstract][hide abstract] ABSTRACT: Urbanization affects communities of herbivorous arthropods and provides opportunities for dramatic changes in their abundance and richness. Underlying these changes are creation of impervious surfaces; variation in the density, diversity, and complexity of vegetation; and maintenance practices including pulsed inputs of fertilizers, water, and pesticides. A rich body of knowledge provides theoretical underpinnings for predicting and understanding impacts of urbanization on arthropods. However, relatively few studies have elucidated mechanisms that explain patterns of insect and mite abundance and diversity across urbanization gradients. Published accounts suggest that responses to urbanization are often taxon specific, highly variable, and linked to properties of urbanization that weaken top-down and/or bottom-up processes, thereby destabilizing populations of herbivores and their natural enemies. In addition to revealing patterns in diversity and abundance of herbivores across urbanization gradients, a primary objective of this review is to examine mechanisms underlying these patterns and to identify potential hypotheses for future testing.
[show abstract][hide abstract] ABSTRACT: Habitat manipulation is a branch of conservation biological control in which vegetation complexity and diversity are increased in managed landscapes to provide food and other resources for arthropod natural enemies. This is often achieved by maintaining noncrop plant material such as flowering strips and beetle banks that provide natural enemies with nectar and pollen, alternative prey, shelter from disturbance, and overwintering sites. In most cases, plant material used in habitat manipulation programs is not native to the area in which it is planted. Using native plant species in conservation biological control could serve a dual function of suppressing pest arthropod outbreaks and promoting other valuable ecosystem services associated with native plant communities. We evaluated 10 plant species native to Maryland for their attractiveness to foliar and ground-dwelling natural enemies. Plants that showed particular promise were Monarda punctata, Pycnanthemum tenuifolium, and Eupatorium hyssopifolium, which generally harbored the greatest abundance of foliar predators and parasitoids, although abundance varied over time. Among ground-dwelling natural enemies, total predator and parasitoid abundance differed between plant species, but carabid and spider abundance did not. Matching certain plant species and their allied natural enemies with specific pest complexes may be enhanced by identifying the composition of natural enemy assemblages at different times of year and in both foliar and ground habitat strata.
[show abstract][hide abstract] ABSTRACT: Preserving arthropod predator abundance and diversity in agricultural ecosystems may reduce pest populations and subsequent loss in yield. However, since natural enemy species vary in their impact on pest populations, it is crucial to identify which predators are effective at reducing pest abundance. Leafrollers spend part of their life on the ground and part in the canopy of vineyards. In this experiment, predation of tethered leafrollers on the ground and in the vine canopy was compared in a New Zealand vineyard. Leafrollers in each stratum were recorded using video equipment to identify predators that were consuming leafrollers. A separate experiment investigated the behavior of Epiphyas postvittana larvae when encountered by earwigs on vines or concealed within leaf shelters. Predation rates of leafrollers did not differ between the ground and canopy strata. However, predator activity, attack rate, and species richness were higher on the ground. Six predator taxa consumed leafrollers on the ground whereas only earwigs consumed leafrollers in the canopy. Earwigs were more active, and killed significantly more leafrollers in the canopy than on the ground, compensating for the relatively low activity and diversity of other predators in that stratum. This research demonstrates the value of video recording in biological control research, as it permits identification of the predators contributing to pest reduction. In addition, it highlights the need to understand the contributions of individual predator taxa to biological control to better conserve the ‘right diversity’ in agricultural systems and benefit from this ecosystem service.
[show abstract][hide abstract] ABSTRACT: This study examined the influence of habitat structural complexity on the collective effects of top-down and bottom-up forces on herbivore abundance in urban landscapes. The persistence and varying complexity of urban landscapes set them apart from ephemeral agroecosystems and natural habitats where the majority of studies have been conducted. Using surveys and manipulative experiments. We explicitly tested the effect of natural enemies (enemies hypothesis), host plant quality, and herbivore movement on the abundance of the specialist insect herbivore, Stephanitis pyrioides, in landscapes of varying structural complexity. This herbivore was extremely abundant in simple landscapes and rare in complex ones. Natural enemies were the major force influencing abundance of S. pyrioides across habitat types. Generalist predators, particularly the spider Anyphaena celer, were more abundant in complex landscapes. Predator abundance was related to greater abundance of alternative prey in those landscapes. Stephanitis pyrioides survival was lower in complex habitats when exposed to endemic natural enemy populations. Laboratory feeding trials confirmed the more abundant predators consumed S. pyrioides. Host plant quality was not a strong force influencing patterns of S. pyrioides abundance. When predators were excluded, adult S. pyrioides survival was greater on azaleas grown in complex habitats, in opposition to the observed pattern of abundance. Similarly, complexity did not affect S. pyrioides immigration and emigration rates. The complexity of urban landscapes affects the strength of top-down forces on herbivorous insect populations by influencing alternative prey and generalist predator abundance. It is possible that habitats can be manipulated to promote the suppressive effects of generalist predators.
[show abstract][hide abstract] ABSTRACT: The use of a standardized beat sampling method for estimating spruce spider mite, Oligonychus ununguis (Jacobi) (Acari: Tetranychidae), densities on a widely used evergreen ornamental plant species, Juniperus chinensis variety 'Sargentii' A. Henry (Cupressaceae), was examined. There was a significant positive relationship between total spruce spider mite densities and spider mite densities from beat sampling on juniper. The slope and intercept of the relationship may be used by pest managers to predict total spider mite densities on plants from beat sample counts. Beat sampling dramatically underestimates the total number of spider mites on a foliage sample. The relationships between spruce spider mite feeding injury and spider mite density estimates from beat sampling juniper foliage and total spider mite counts on foliage were also examined. There was a significant positive relationship between spruce spider mite density as estimated from beat sampling and injury to the plants. There was a similar positive relationship between the total number of spruce spider mites and injury to the plants, suggesting that a pest manager could use beat sampling counts to estimate plant injury and related thresholds. These findings have important implications to decision-making for spruce spider mite control, especially as it relates to threshold levels and determining rates of predator releases. Further assessment of the effectiveness of beat and other sampling methods across multiple spider mite- host plant associations needs to be examined to enable pest managers to select sampling plans that are feasible and reliable.
Journal of Economic Entomology 09/2004; 97(4):1444-9. · 1.60 Impact Factor
[show abstract][hide abstract] ABSTRACT: The citrus mealybug, Planococcus citri (Risso) (Hemiptera: Pseudococcidae), is one of the most common and damaging insect pests in greenhouses and protected cultures. Pesticides are frequently used, often unsuccessfully, to control this pest. Our objective was to determine the influence of water and nutrient management practices on mealybug populations and their impact on the efficacy of augmentative releases of Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae), a mealybug predator. Studies were conducted on Heuchera micrantha 'Palace Purple' growing in protected culture. Heuchera plants received 3 rates of nitrogen: low (25 ppm/wk), medium (75 ppm/wk), and high (150 ppm/wk). Within each fertilizer treatment plants were either water stressed or not water stressed. In the absence of predators, citrus mealybug populations increased dramatically on water stressed plants receiving high and low levels of fertilizer. Cryptolaemus montrouzieri reduced mealybug populations and consistently had the greatest impact on mealybugs where mealybugs were the most abundant, regardless of fertilizer or water treatment. In the presence of predators, mealybug populations are regulated by predation rather than mealybug interactions with fertilizer or water. This data suggests plant management practices that avoid high or low rates of fertilization of water stressed plants should reduce the outbreak potential of citrus mealybug. If mealybugs do outbreak, implementing augmentative biological control with C. montrouzieri should be effective regardless of fertilization and irrigation practices.
[show abstract][hide abstract] ABSTRACT: A laboratory trial evaluated four phytoseiid species for their potential as biological control agents of spruce spider mite, Oligonychus ununguis (Jacobi) (Acari: Tetranychidae). An augmentative biological control approach, using the predatory mites Neoseiulus fallacis Garman and Galendromus occidentalis Nesbitt (Acari: Phytoseiidae), was evaluated for reducing pest mite densities and injury, and economic costs on Juniperus chinensis 'Sargentii' A. Henry (Cupressaceae) in an outdoor nursery. Sequential releases of predator species, individually and in combination, were tested and compared with two commonly used miticides, a low-toxicity miticide, horticultural oil, and a conventional miticide, hexythiazox. Timing of treatments was based on grower-determined need, and predator release rates were based on guidelines in literature received from producers of beneficial organisms. Predator releases were more expensive and provided less effective suppression of spruce spider mites, resulting in greater spider mite injury to plants, compared with conventional pesticides. However, spider mite damage to plants did not differ in an economically meaningful way between treatments. Unsatisfactory levels of control seem related to under estimations of actual spider mite abundance based on grower perceptions and the beat sampling technique used to estimate predator release rates. These data suggest that when initial populations of spruce spider mite are high, it is unlikely that sequential releases of predator species, individually or in combination, will suppress spider mite populations. In this trial, augmentative biological control control was 2.5-7 times more expensive than chemical controls.
Journal of Economic Entomology 01/2004; 96(6):1675-84. · 1.60 Impact Factor
[show abstract][hide abstract] ABSTRACT: The relationship between azalea lace bug, Stephanitis pyrioides (Scott), abundance and components of vegetational texture were examined in managed landscapes to determine which component(s) best explained patterns in lace abundance. In managed landscapes, azalea lace bug is a key pest of azaleas and its abundance varies dramatically in time and space. The components of vegetational texture examined were light exposure, plant species diversity, evenness and richness, host patch size, and structural complexity of the landscape. The best habitat predictors of lace bug abundance were structural complexity and light exposure explaining 54 and 53% of lace bug variation, respectively. Three of the remaining four components also were significantly related to lace bug abundance. Further examination of light exposure revealed that afternoon readings explained more of the variation (52%) in lace bug abundance than morning readings (9%). Of the five vegetational strata that comprise structural complexity, the overstory tree layer and ground cover/turf layer (76%) were the best predictors of lace bug abundance. The implications of this work are that landscapes can be evaluated for susceptibility to lace bugs and perhaps other pests. It also provides information for designing landscapes that support fewer pest problems, resulting in low-input sustainable landscapes.
[show abstract][hide abstract] ABSTRACT: Cover sprays and residual insecticides are tactics used by landscapers and arborists to control arthropod pests on trees and shrubs in urban settings. Trees in residential landscapes that received three cover sprays annually for at least 4 years harbored a greater diversity of scale insect pests and were much more likely to be infested with scales than trees in landscapes treated with cover sprays for shorter peri- ods of time. Oak (Quercus palustris) trees in an institu- tional landscape treated with residual insecticides harbored significantly lower numbers of beneficial arthropods than trees treated with a pesticide that lacked residual activity. The suppressive effect of the residual insecticides on natural enemies was pro- nounced on the community of parasitic wasps that at- tack the obscure scale (Melanaspis obscura), a common scale insect pest of oak. The effect of residual insecti- cides on individual wasp species persisted 4 weeks after the pesticides were applied. By reducing the use of cover sprays and residual insecticides, arborists may be able to conserve conimunities of natural enemies in managed landscapes. This will enhance the bio- logical diversity of beneficial insects found in urban forests and thereby aid in increasing their sustainability.
[show abstract][hide abstract] ABSTRACT: An analysis of data collected from 212 resi- dential landscapes in suburban Maryland, U.S., re- vealed significant positive relationships between the number of insect and mite pests in the landscape and the total number of plants and plant species at the site. The number of pests in a landscape increased very little in relation to the number of plants found in the landscape. However, the number of arthropod pests increased at a much greater rate as more species of plants were added. Two explanations for these results are likely. Relatively few plants harbored arthropod pests throughout the course of the season. Adding more plants of the same species had little effect on altering the number of pest species in a landscape. Arthropod pests tend to be relatively specialized in their host range. When different species of plants are added to a landscape, more opportunities are created for specialized insects and mites to colonize the site and increase the richness of the arthropod fauna. When used in conjunction with previous investiga- tions involving monitoring approaches, these results help IPM and PHC monitors plan and conduct site inspections more efficiently and effectively.