Novel lighting technology offers the possibility of improved arthropod integrated pest management (IPM) in artificially lighted crops. This review compiles the current knowledge on how greenhouse pest and beneficial arthropods are directly affected by light, with the focus on whiteflies. The effect of ultraviolet depletion on orientation and colour‐coded phototaxis are to some extent studied and utilised for control of the flying adult stage of some pest species, but far less is known about the visual ecology of commercially used biological control agents and pollinators, and about how light affects arthropod biology in different life stages. Four approaches for utilisation of artificial light in IPM of whiteflies are suggested: (a) use of attractive visual stimuli incorporated into traps for monitoring and direct control, (b) use of visual stimuli that disrupt the host‐detection process, (c) radiation with harmful or inhibitory wavelengths to kill or suppress pest populations and (d) use of time cues to manipulate daily rhythms and photoperiodic responses. Knowledge gaps are identified to design a road map for research on IPM in crops lighted with high‐pressure sodium lamps, light‐emitting diodes (LEDs) and photoselective films. LEDs are concluded to offer possibilities for behavioural manipulation of arthropods, but the extent of such possibilities depends in practice on which wavelength combinations are determined to be optimal for plant production. Furthermore, the direct effects of artificial lighting on IPM must be studied in the context of plant‐mediated effects of artificial light on arthropods, as both types of manipulations are possible, particularly with LEDs.

Inducible terpenes and lipoxygenase pathway products, e.g., green-leaf volatiles (GLVs), are emitted by plants in response to herbivory. They are used by carnivorous arthropods to locate prey. These compounds are highly reactive with atmospheric pollutants. We hypothesized that elevated ozone (O(3)) may affect chemical communication between plants and natural enemies of herbivores by degrading signal compounds. In this study, we have used two tritrophic systems (Brassica oleracea-Plutella xylostella-Cotesia plutellae and Phaseolus lunatus-Tetranychus urticae-Phytoseiulus persimilis) to show that exposure of plants to moderately enhanced atmospheric O(3) levels (60 and 120 nl l(-1)) results in complete degradation of most herbivore-induced terpenes and GLVs, which is congruent with our hypothesis. However, orientation behavior of natural enemies was not disrupted by O(3) exposure in either tritrophic system. Other herbivore-induced volatiles, such as benzyl cyanide, a nitrile in cabbage, and methyl salicylate in lima bean, were not significantly reduced in reactions with O(3). We suggest that more atmospherically stable herbivore-induced volatile compounds can provide important long-distance plant-carnivore signals and may be used by natural enemies of herbivores to orientate in O(3)-polluted environments.

Tropospheric ozone (O3) is an important secondary air pollutant formed as a result of photochemical reactions between primary pollutants, such as nitrogen oxides (NOx), and volatile organic compounds (VOCs). O3 concentrations in the lower atmosphere (troposphere) are predicted to continue increasing as a result of anthropogenic activity, which will impact strongly on wild and cultivated plants. O3 affects photosynthesis and induces the development of visible foliar injuries, which are the result of genetically controlled programmed cell death. It also activates many plant defense responses, including the emission of phytogenic VOCs. Plant emitted VOCs play a role in many eco-physiological functions. Besides protecting the plant from abiotic stresses (high temperatures and oxidative stress) and biotic stressors (competing plants, micro- and macroorganisms), they drive multitrophic interactions between plants, herbivores and their natural enemies e.g., predators and parasitoids as well as interactions between plants (plant-to-plant communication). In addition, VOCs have an important role in atmospheric chemistry. They are O3 precursors, but at the same time are readily oxidized by O3, thus resulting in a series of new compounds that include secondary organic aerosols (SOAs). Here, we review the effects of O3 on plants and their VOC emissions. We also review the state of current knowledge on the effects of ozone on ecological interactions based on VOC signaling, and propose further research directions.

This review describes the effects of the current and emerging lighting technologies on plants, and the plant‐mediated effects on herbivorous and beneficial arthropods in high‐technology year‐round greenhouse production, where light quality, quantity and photoperiod differ from the natural environment. The spectrum provided by the current lighting technology, high‐pressure sodium lamp (HPSL), differs considerably from that of solar radiation. The major plant‐mediated effects on arthropods were predicted to result from (a) extended photoperiods and lower light integrals, (b) the attenuation of ultraviolet (UV) wavelengths, particularly UV‐B, (c) the high red: far‐red (R : FR) ratio and lower blue : red (B : R) in comparison with solar radiation and (d) the high proportion of yellow wavelengths during winter months. Of these light factors (a–d) (ceteris paribus), (a) and (b) were hypothesised to result in increased performance of herbivores in winter months, whereas the high R : FR ratio decreased herbivore performance or not affected it, at least when interlights are used. The predictions obtained on the basis of this review are also discussed in relation to the modifying factors prevailing in these production environments: enriched CO2 levels, high nutrient amounts, optimised irrigation and temperatures optimal for plants' needs. Based on the carbon/nitrogen and growth/differentiation balance theories, these modifying factors tend to produce plants that allocate most resources to growth at the expense of defensive secondary metabolism and physicochemical defensive structures. At the end, this review discusses knowledge gaps and future research prospects, in which light‐emitting diodes, the emerging lighting technology, play an important role by enabling the targeted manipulation of plant responses to different wavelengths.

Does transgenically incorporated insect resistance affect constitutive and herbivore-inducible terpenoid emissions and multitrophic communication under elevated atmospheric CO(2) or ozone (O(3))? This study aimed to clarify the possible interactions between allocation to direct defences (Bacillus thuringiensis (Bt) toxin production) and that to endogenous indirect defences under future climatic conditions. Terpenoid emissions were measured from vegetative-stage non-Bt and Bt Brassica napus grown in growth chambers under control or doubled CO(2), and control (filtered air) or 100 ppb O(3). The olfactometric orientation of Cotesia vestalis, an endoparasitoid of the herbivorous diamondback moth (Plutella xylostella), was assessed under the corresponding CO(2) and O(3) concentrations. The response of terpenoid emission to CO(2) or O(3) elevations was equivalent for Bt and non-Bt plants, but lower target herbivory reduced herbivore-inducible emissions from Bt plants. Elevated CO(2) increased emissions of most terpenoids, whereas O(3) reduced total terpenoid emissions. Cotesia vestalis orientated to host-damaged plants independent of plant type or CO(2) concentration. Under elevated O(3), host-damaged non-Bt plants attracted 75% of the parasitoids, but only 36.8% of parasitoids orientated to host-damaged Bt plants. Elevated O(3) has the potential to perturb specialized food-web communication in Bt crops.