Olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), is the major pest of commercial olives worldwide. Various aspects of its biology, ecology, management, and impact on olive production ...are highlighted. With the discovery of insecticidal resistance in some populations frequently treated with organophosphates, old and new control options are being investigated. The potential of biological control is examined. Surveys suggest that a small group of braconids in the Opiinae subfamily best represent the primary parasitoids attacking olive fruit fly in its native range. These species include Psyttalia lounsburyi, P. dacicida, P. concolor, P. ponerophaga, and Utetes africanus. Bracon celer, another braconid but in the Braconinae subfamily, is also reared from the fruit fly in its native range. The potential of these and other natural enemies is discussed with respect to olive fruit fly biology, commercial olive production, and biological constraints that may limit their success. We suggest that numerous species exist that should be further investigated as control agents for olive fruit fly in the many climatic regimes where the pest is found.
The Asian vinegar fly Drosophila suzukii (spotted wing Drosophila SWD) has emerged as a major invasive insect pest of small and stone fruits in both the Americas and Europe since the late 2000s. ...While research efforts have rapidly progressed in Asia, North America, and Europe over the past 5 years, important new insights may be gained in comparing and contrasting findings across the regions affected by SWD. In this review, we explore common themes in the invasion biology of SWD by examining (1) its biology and current pest status in endemic and recently invaded regions; (2) current efforts and future research needs for the development of predictive models for its geographic expansion; and (3) prospects for both natural and classical (=importation) biological control of SWD in invaded habitats, with emphasis on the role of hymenopteran parasitoids. We conclude that particularly fruitful areas of research should include fundamental studies of its overwintering, host-use, and dispersal capabilities; as well as applied studies of alternative, cost-effective management techniques to complement insecticide use within the integrated pest management framework. Finally, we emphasize that outreach efforts are critical to effective SWD management by highlighting successful strategies and insights gained from various geographic regions.
Functional response describes the number of prey or hosts attacked by a predator or parasitoid as a function of prey or host density. Using three different experimental designs, we found a linear ...functional response by two insect parasitoids (the pteromalid Pachycrepoideus vindemiae and the diapriid Trichopria drosophilae) to their hosts (the drosophilids Drosophila suzukii and D. melanogaster). A linear function response is considered unusual for insect parasitoids. The first design was a 'fixed time within patch experiment' where individual parasitoids were exposed to a range of host densities for 24 h; the second two designs were a 'variable time functional response' and a 'selective functional response' experiments where individual parasitoids were presented with a range of host patches and allowed to freely select and explore only one patch (variable time) or forage for 24 h (selective). In all experimental designs, the number of hosts parasitized increased linearly until reaching an upper limit. Under the laboratory conditions used, the functional response of P. vindemiae was limited by its egg supply and time (host handling time) whereas T. drosophilae was limited by time only. The linear functional response by both parasitoids likely resulted from a constant attack rate and an incremental foraging strategy where the parasitoids left a poor (low density) host patch or remained in a higher quality host patch when there was successful oviposition and adequate host density.
Temperature-dependent fecundity and survival data was integrated into a matrix population model to describe relative Drosophila suzukii Matsumura (Diptera: Drosophilidae) population increase and age ...structure based on environmental conditions. This novel modification of the classic Leslie matrix population model is presented as a way to examine how insect populations interact with the environment, and has application as a predictor of population density. For D. suzukii, we examined model implications for pest pressure on crops. As case studies, we examined model predictions in three small fruit production regions in the United States (US) and one in Italy. These production regions have distinctly different climates. In general, patterns of adult D. suzukii trap activity broadly mimicked seasonal population levels predicted by the model using only temperature data. Age structure of estimated populations suggest that trap and fruit infestation data are of limited value and are insufficient for model validation. Thus, we suggest alternative experiments for validation. The model is advantageous in that it provides stage-specific population estimation, which can potentially guide management strategies and provide unique opportunities to simulate stage-specific management effects such as insecticide applications or the effect of biological control on a specific life-stage. The two factors that drive initiation of the model are suitable temperatures (biofix) and availability of a suitable host medium (fruit). Although there are many factors affecting population dynamics of D. suzukii in the field, temperature-dependent survival and reproduction are believed to be the main drivers for D. suzukii populations.
Drosophila suzukii has become a key invasive pest of soft- and thin-skinned fruit crops in its invaded regions in Europe and Americas, where naturally occurring natural enemies are generally not ...effective for the suppression of this pest or largely absent such as larval-attacking parasitoids. As a part of systematic evaluations of candidate agents for classical biological control of this invasive pest, we evaluated the functional responses of three Asian-native larval hymenopteran parasitoids, Asobara japonica (Braconidae), Ganaspis brasiliensis, and Leptopilina japonica (both Figitidae) to D. suzukii or Drosophila melanogaster (A. japonica only) larvae. Host larval densities were 5, 10, 15, 20, 25, 30, 35, or 40 larvae per test for A. japonica and 3, 6, 9, 12, 18, 24, 30, 36, or 42 larvae per test for G. brasiliensis or L. japonica. Host larvae were provided in standard artificial diet in tubes for a 24-h exposure to individual female parasitoids under the quarantine conditions (23°C). All three parasitoids showed a linear (type I) functional response to the tested host densities. Host species (for A. japonica only) did not affect the number of hosts parasitized or the functional response. Asobara japonica was more efficient than either figitid in terms of the searching efficiency while L. japonica preformed slightly better than G. brasiliensis under the tested conditions.The results are discussed with respect to the selection of parasitoid species to be released in North America and Europe to suppress D. suzukii.
Detailed description of antennal sensory organs of Leptoglossus occidentalis Heidemann, 1910 (Insecta: Hemiptera: Heteroptera: Coreidae) and a comparison with L. zonatus (Dallas, 1852) are presented. ...A novel approach that combines the advantages of field emission scanning electron microscopy (FE-SEM) and atomic force microscope (AFM) was used to detail micromorphological structures. A simplified classification system for sensilla that eliminates the subjective aspects of morphology, such as their shape, is proposed. Fourteen sensory organs have been classified into three main groups: (a) aporous sensilla with a flexible socket, (b) porous sensilla with a flexible socket and (c) porous sensilla with an inflexible socket. A large variety of sensory organs (nine types) with olfactory functions are described. The antennal sensory organs have been recognized as one of the factors responsible for the evolutionary success of Leptoglossus spp. and their status as important pests and invasive species.
Viticulture has experienced dramatic global growth in acreage and value. As the international exchange of goods has increased, so too has the market demand for sustainably produced products. Both ...elements redefine the entomological challenges posed to viticulture and have stimulated significant advances in arthropod pest control programs. Vineyard managers on all continents are increasingly combating invasive species, resulting in the adoption of novel insecticides, semiochemicals, and molecular tools to support sustainable viticulture. At the local level, vineyard management practices consider factors such as the surrounding natural ecosystem, risk to fish populations, and air quality. Coordinated multinational responses to pest invasion have been highly effective and have, for example, resulted in eradication of the moth
Lobesia botrana
from California vineyards, a pest found in 2009 and eradicated by 2016. At the global level, the shared pests and solutions for their suppression will play an increasing role in delivering internationally sensitive pest management programs that respond to invasive pests, climate change, novel vector and pathogen relationships, and pesticide restrictions.
Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae) is a polyphagous insect pest attacking a wide variety of crops. In California's Central Valley, it is now the dominant leaffooted bug on almonds, ...pistachios, and pomegranates. Leptoglossus zonatus pest status depends largely on overwintering adult survival and reproductive potential, which determines its population size in spring and early summer when nut crops are particularly susceptible to bug damage. Here, we investigated the overwintering reproductive biology of L. zonatus in laboratory and field experiments to gain information about its ovary development, time of mating, and the impact of low temperatures on egg hatch. With dissections of laboratory-reared L. zonatus, we established a baseline for ovarian development and determined that the size of the spermathecal reservoir is larger in mated than in unmated females. Dissections and behavioral experiments of field-collected material provided evidence of mating events before dispersal from overwintering sites. Laboratory trials showed that temperature significantly impacted L. zonatus egg hatch. Leptoglossus zonatus reproductive biology presented provides valuable information on its population dynamics and dispersal from overwintering sites, and will contribute to the development of monitoring and management tools.
Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is a polyphagous insect pest that has invaded much of the United States, including California. Despite model predictions that regions in California ...like the agriculturally important Central Valley are suitable, H. halys populations and the occurring crop damage are distinctly lower than in regions of the East Coast. To evaluate if this is due to low nymphal survival in the high temperature and intensive monoculture environment, H. halys nymphs were caged on four common Central Valley tree crops: almond, pistachio, peach, and grape, and compared to the well-established almond and pistachio pest Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae). Nymphal development showed that peach, almond, and pistachio can sustain H. halys as single host plants until adult eclosion, whereas grapes cannot. The addition of fruiting structures of almond, pistachio, and grape to H. halys caged on peach trees (= mixed diet) did not increase nymphal survival but did increase adult female size. Leptoglossus zonatus survival was higher than H. halys on pistachio, but not on the other crops. Overall, H. halys nymphal mortality in the field was high, with 92% in the mixed diet compared to 73% in the mixed diet control in the laboratory, indicating abiotic population pressures. Our results confirm peach as a good H. halys host plant and suggest that almond has a similar suitability, and while pistachios can support H. halys nymphal development, they seem less likely to facilitate population growth.
1. Mechanisms responsible for the success or failure of agricultural diversification are often unknown. Most studies of arthropod pest management focus on enhancing natural enemy effectiveness. ...However, non-crop plants can also change crop host quality by reducing or adding soil nutrients or water, and therefore improve or hamper pest suppression. Native perennial ground covers may provide food or habitat to natural enemies and, in terms of competition for soil nutrients or water, be more compatible with crop management than exotic annuals. 2. We conducted a 3-year vineyard study to examine the impacts of native perennial grasses on pests, natural enemies, crop plant condition and soil properties. We included three ground cover treatments: bare soil with a grower standard drip irrigation; native grasses with drip irrigation; and native grasses with drip irrigation as well as an additional flood irrigation to keep the grasses green and growing during the season. 3. Numbers of leafhopper pests Erythroneura spp. decreased in both native grass treatments, where parasitism rates were higher. Vine petiole nitrate levels were lower in grass treatments, indicating competition for soil nitrogen, which is most often considered to be detrimental. Berry weight was higher in the irrigated treatment but did not differ between the bare soil and non-irrigated grass treatment. Grape °Brix was similar in the bare soil and native grass treatments, suggesting native grasses did not compromise grape quality. In fact, leaf water stress was lower and soil moisture higher not only in the irrigated grass treatment but, at times, in the non-irrigated grass treatment, compared with the bare soil treatment. 4. synthesis and applications. Our work shows that native grasses contribute to a reduction in vineyard leafhopper pests by reducing host quality through competition for soil nitrogen and providing food resources and/or habitat for natural enemies. Native grasses also improve soil water content and may be part of a water conservation program for perennial crops in dry climate regions.
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