Western flower thrips, Frankliniella occidentalis, first arose as an important invasive pest of many crops during the 1970s–1980s. The tremendous growth in international agricultural trade that developed then fostered the invasiveness of western flower thrips. We examine current knowledge regarding the biology of western flower thrips, with an emphasis on characteristics that contribute to its invasiveness and pest status. Efforts to control this pest and the tospoviruses that it vectors with intensive insecticide applications have been unsuccessful and have created significant problems because of the development of resistance to numerous insecticides and associated outbreaks of secondary pests. We synthesize information on effective integrated management approaches for western flower thrips that have developed through research on its biology, behavior, and ecology. We further highlight emerging topics regarding the species status of western flower thrips, as well as its genetics, biology, and ecology that facilitate its use as a model study organism and will guide development of appropriate management practices.

The displacement of a species from a habitat by actions of another is the most severe outcome of interspecific interactions. This review focuses on recent developments in the understanding of (a) ecological mechanisms that lead to displacements, (b) how outcomes of interspecific interactions are affected by the context of where and when they occur, and (c) impacts of displacements. Displacements are likely to escalate as their primary initiating factors—the spread of non-native species and environmental change—continue at unprecedented rates. Displacements typically result from interactions of multiple mechanisms, not all of which involve direct competition. Various biotic and abiotic factors mediate these mechanisms, so variable outcomes occur when the same species interact in different environments. Though replacement of one species by another has particular relevance to pest management and conservation biology, the cascading effects that displacements have in managed and natural systems are critical to understand.

Integrated pest management (IPM) is an educated and systematic effort to use multiple control techniques to reduce pest damage to economically acceptable levels while minimizing negative environmental impacts. Although its benefits are widely acknowledged, IPM is not universally practiced by farmers. Potato farming, which produces one of the most important staple crops in the world, provides a good illustration of the issues surrounding IPM adoption. Potatoes are attacked by a complex of insect pests that can inflict catastrophic crop losses. Potato production has gone through the processes of consolidation and intensification, which are linked to increased pest problems, particularly selection for insecticide-resistant pest populations. While use of insecticides remains the most common method of pest control in potatoes, other techniques, including crop rotation and natural enemies, are also available. In addition, there are effective monitoring techniques for many potato pests. However, reliable economic thresholds are often lacking. Potato ecosystems are complex and diverse; therefore, the knowledge necessary for developing ecologically based pest management is not easily obtained or transferable. Furthermore, potato systems change with the arrival of new pest species and the evolution of existing pests. Modern technological advances, such as remote sensing and molecular biotechnology, are likely to improve potato IPM. However, these tools are not going to solve all problems. IPM is not just about integrating different techniques; it is also about integrating the efforts and concerns of all stakeholders. The collaboration of farmers and scientists in agricultural research is needed to foster the development of IPM systems that are appropriate for grower implementation and thus more likely to be adopted. Additional emphasis also needs to be placed on the fact that not only does IPM decrease degradation of the environment, but it also improves the economic well-being of its practitioners.

Western flower thrips (WFT) is one of the most important pests of horticultural crops worldwide because it can damage many different crops and transmit various plant viruses. Given these significant impacts on plant production, novel methodologies are required to maximize regulation of WFT to minimize crop losses. One particular approach is to develop control strategies for the non-feeding, soil-dwelling stages of WFT. Control of these stages could be enhanced through the use of granules impregnated with entomopathogenic fungi mixed in the soil. The use of soil-applied fungi contrasts with existing approaches in which entomopathogenic fungi are formulated as oil-based suspensions or water-based wettable powders for foliar applications against the feeding stages of WFT. To examine the efficacy of this approach, we evaluated the effects of a granular formulation of Beauveria bassiana on the soil-dwelling, pupal phases of Frankliniella occidentalis in laboratory bioassays and greenhouse experiments. Based on micromorphological observations of fungal conidia during the infection process after treatment of WFT with a B. bassiana suspension, fungal conidia complete the process of surface attachment, germination, and penetration of the body wall of the WFT pupa and enter the host within 60 h of treatment. Given these results, we undertook a controlled greenhouse experiment and applied B. bassiana granules to soil used to cultivate eggplants. Populations of F. occidentalis on eggplants grown in treated soil were 70% lower than those on plants grown in the untreated soil after 8 weeks. Furthermore, when measuring the survival and growth of B. bassiana on granules under different soil moisture conditions, survival was greatest when the soil moisture content was kept at 20%. These results indicate that the application of B. bassiana-impregnated granules could prove to be an effective biological control strategy for use against F. occidentalis under greenhouse conditions.

The entomopathogen Beauveria bassiana (Bals.) Vuill. (Ascomycota: Hypocreales) can colonize plants endophytically and stimulate the production of secondary plant metabolites with anti-herbivore activities. We assayed the topical virulence of B. bassiana to Aphis gossypii Glover (Hemiptera: Aphididae), the effects of cucumber inoculation with this fungus on plant metabolites, and the physiological consequences for aphids that fed on these plants. Assays were conducted with both the commercial formulation of B. bassiana, 'Naturalis^®-L', at the recommended concentration of 1.5 ml / L (yielding a spore concentration of 2.3 ? 10⁷ CFU per ml), and with a similar concentration of the isolated fungal strain. Topical application of 0.03 ml of solution per cm², or 1 ? 10³ CFU, caused 100% mortality to A. gossypii adults after seven days, whether Naturalis^®-L or the isolate alone was used. The fungus grew endophytically into foliage when sprayed on cucumbers at the 2-leaf stage and concentrations of alkaloids, flavonoids, phenols, hydrogen peroxide, and total chlorophyll were higher than in control plants 28 days after inoculation. Malondialdehyde content, plant growth, and total yield were unaffected by B. bassiana inoculation. Aphids fed on B. bassiana-inoculated plants for 24 h had reduced activities of detoxifying enzymes (glutathione-S-transferase, carboxylesterase, and acetylcholinesterase) compared to controls. Activities of digestive enzymes, (lipase, α-amylase, α-glucosidase, and aminopeptidase) were reduced in aphids from inoculated plants, which exhibited higher activities of superoxide dismutase, ascorbate peroxidase, and phenoloxidase, but lower catalase activity. Energy reserves (lipids, protein, and glycogen) were lower in aphids from inoculated plants, and they exhibited reduced fecundity, longevity, and reproductive periods, and a 50% reduction in the LC₅₀ of pirimicarb. Thus, in addition to causing direct pathogenicity, inoculation of plants with B. bassiana negatively impacted A. gossypii physiology and reproductive performance and could usefully complement other strategies for managing cotton aphids on greenhouse cucumber.

Secondary plant metabolites can affect parasitoids directly or indirectly through their action on the parasitoid host. We assessed if the linear furanocoumarins, psoralen, bergapten and xanthotoxin, secondary plant metabolites present in Apium spp. and other taxa, exerted direct or indirect effects on Copidosonma floridanum (Ashmead), a polyembryonic parasitoid of Trichoplusia ni (Hübner), through diet incorporation bioassays. Because linear furanocoumarins are photoactivated, we tested for these effects in the presence and absence of UV radiation. Increasing concentrations of linear furanocoumarins prolonged larval development of T. ni, but resulted in greater pupal mass. Furthermore, increasing concentrations of linear furanocoumarins increased T. ni mortality, but only marginally. However, increasing concentrations of linear furanocoumarins in the host diet significantly increased mortality of the parasitoid. There were no significant differences in the number of reproductive parasitoid larvae among treatments, indicating that linear furanocoumarins did not interfere with polyembryonic development of C. floridanum, but exerted toxicity after the parasitoid larvae began feeding on host tissue. Supplemental UV radiation slowed development, but it did not affect survival of either T. ni or C. floridanum. Because of the differential effects on the host and parasitoid, linear furanocoumarins, at naturally occurring concentrations, can mediate this host–parasitoid relationship through direct effects on the parasitoid, and not merely as a consequence of their effect on the host.