Marvin Pec

While herbivore-induced plant volatiles are well-established cues that guide natural enemies to herbivores in ecosystems, microbe-induced plant volatiles have recently gained attention as promising tools for achieving similar outcomes. However, how nocturnal predators respond to volatile cues induced by herbivory and/or endophytic fungal remains poorly understood, particularly in systems where the predator and plant do not share a tightly co-evolved or highly specialized relationship. To explore this, we investigated whether Spodoptera frugiperda infestation and Metarhizium robertsii endophytic colonization in sugarcane plants could enhance the olfactory attraction of the nocturnal earwig predator Doru luteipes by modifying nocturnal volatile emissions and altering endogenous levels of jasmonic acid and salicylic acid. Unexpectedly, the changes in volatile emissions and phytohormone levels induced by herbivory and microbial colonization led to a reduced attraction of the predator compared with undamaged control plants and with the no-plant control. These findings highlight the complexity of D. luteipes’ responses to induced indirect defenses in sugarcane, suggesting that such strategies may not consistently enhance the recruitment of natural enemies.

BACKGROUND: Silicon (Si) fertilization has been well‐documented to enhance plant resistance against insect pests by increasing the abrasiveness and toughness of leaf tissues. Additionally, Si also interacts with the jasmonic acid pathway, which modulates antiherbivore induced defenses, including the emission of herbivore‐induced plant volatiles (HIPVs) that attract natural enemies. In this study, we examined the influence of Si fertilization on the attractiveness of nocturnal HIPVs from maize plants infested with the fall armyworm (FAW), Spodoptera frugiperda (JE Smith), to the predatory earwig Doru luteipes (Scudder). RESULTS: In laboratory assays, we found that Si fertilization did not alter the attractiveness of nocturnal constitutive volatiles to the nocturnal predator D . luteipes . However, upon infestation with FAW larvae, Si‐fertilized plants emitted a volatile blend that was more attractive to D. luteipes . Although the composition of HIPVs emitted by non‐fertilized and Si‐fertilized plants was similar, the terpene neryl acetate was exclusively detected in the HIPV blend from Si‐fertilized plants. Tests with synthetic neryl acetate demonstrated that the terpene alone was attractive to the earwig at the specific concentration found in the HIPV blend emitted by Si‐fertilized plants. CONCLUSION: This study demonstrates that Si fertilization primes indirect defenses by specifically increasing the amount of neryl acetate in the HIPV blend, which is responsible for the enhanced attractiveness to the predatory earwig. Thus, Si can act as a priming agent of indirect plant defenses, potentially increasing the recruitment of the predatory earwig once plants are infested by FAW, thereby contributing to suppress insect pest populations. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

A diverse orchard with fruit fly hosts may provide information about trophic relationships, including new insights into beneficial insects. We evaluated the composition of the fruit fly complex to provide information on tephritid species, parasitoids and multitrophic interactions for the southern region of Minas Gerais, Brazil. Sampling was carried out using traps and by collecting fruits from plants and/or the ground according to availability/the fruiting period. Occurrences of Anastrepha amita Zucchi and A. punctata Hendel were recorded for the first time in the state of Minas Gerais, and new trophic associations were obtained for A. bahiensis Lima, A. bistrigata Bezzi, A. fraterculus (Wiedemann), A. obliqua (Macquart) and Ceratitis capitata (Wiedemann). Ten tephritid species were obtained from trap sampling, with C. capitata, A. fraterculus and A. obliqua being the most abundant. Five species of fruit flies and seven species of parasitoids were obtained from fruits. The braconid Doryctobracon areolatus (Szépligeti) was the most frequently collected among the parasitoid species. Pitanga (Eugenia uniflora L.) and purple guava (Psidium myrtoides O. Berg) fruits were classified as repositories of fruit fly parasitoids.

Herbivory by insects leads to changes in both primary and secondary plant metabolism, ultimately impacting subsequent interactions. Some phloem‐feeding insects have developed mechanisms to suppress herbivore‐induced plant defences and manipulate the quality of host phloem sap, thereby facilitating their establishment on the host plant. Based on evidence that the specialized phloem‐feeding insects, Dalbulus maidis and Rhopalosiphum maidis , can suppress herbivore‐induced defences in maize, we hypothesized that infestation by either of these pests in maize would facilitate the colonization and establishment of subsequent conspecific and heterospecific individuals. We conducted a series of behavioural assays with these insects in both laboratory and greenhouse settings. The corn leafhopper D. maidis preferred previously infested plants as hosts, but it did not discriminate between conspecific‐ or heterospecific‐infested plants for colonization. However, when selecting a host for oviposition, it preferred depositing eggs on conspecific‐infested plants, which were the hosts that the offspring performed better compared to both non‐infested and heterospecific‐infested plants. The corn aphid R. maidis also preferred previously infested plants over non‐infested plants as hosts. However, the aphid preferred heterospecific‐infested over conspecific‐infested plants, even though heterospecific‐infested plants were hosts of lower quality to aphids. Aphids performed better on conspecific‐infested plants, followed by heterospecific‐infested plants, when compared to non‐infested plants. Our results confirm that previous colonization by the specialized phloem‐feeding insects facilitates subsequent infestations by conspecifics and heterospecifics. However, the facilitation for heterospecifics was asymmetric, as colonization by D. maidis facilitated infestations by R. maidis more than the reverse sequence of infestation.

Southern red mite, Oligonychus ilicis McGregor (Acari: Tetranychidae), is an important polyphagous spider mite pest that causes economic damage to many ornamentals, coffee, and fruit crops. Blueberry growers in the Southeastern United States, including Florida and Georgia, have experienced severe losses due to outbreaks of O. ilicis. Predatory mites are an important management tool used for controlling spider mites; however, predators have not been studied and successfully evaluated in blueberry systems. Amblyseius swirskii Athias-Henriot, Phytoseiulus persimilis Athias-Henriot, and Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) are among the most economically important arthropod agents used in augmentative biological control worldwide. To evaluate the potential of these 3 commercially available predatory mites for use in blueberry plantings, we conducted experiments under controlled laboratory conditions and in the greenhouse. In preliminary laboratory experiments, P. persimilis and N. californicus significantly reduced the number of O. ilicis motile stages below those found in the untreated control, indicating the potential for these 2 predatory mite species to suppress O. ilicis populations. Amblyseius swirskii did not perform well controlling O. ilicis motiles in the laboratory. Under greenhouse conditions, N. californicus and P. persimilis significantly reduced the number of eggs after 7 days of release and the number of motile stages after 14 days of release. This is the first report of using phytoseiid mites to suppress O. ilicis in blueberry systems in the United States. Further studies on predator behavior, feeding preferences, and acaricide compatibility with predators are required to investigate the possibility of using P. persimilis, and N. californicus as biological control agents of O. ilicis in blueberry systems.

Research efforts have been made to develop novel tactics, such as those targeting behavioral control, for management of the Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Psyllidae), vector of the causal agent of citrus Huanglongbing. Here, we investigated whether association of “Ponkan” mandarin (Citrus reticulata) with volatiles from non-host crops: avocado, passion fruit or coffee, alters host location by the Asian citrus psyllid; and whether they can be temporary hosts for the Asian citrus psyllid. In wind tunnel assays, we found that the association of mandarin seedling with avocado plant volatiles reduced in 30% the number of psyllids sitting on host plants compared to the mandarin alone. In contrast, passion fruit plant volatiles facilitated host location by psyllids, which found mandarin seedlings faster than when exposed to mandarin alone. The association with coffee volatiles did not alter the attractiveness of mandarin to the Asian citrus psyllid. Survival and half-lethal time (LT₅₀) of D. citri fed on non-host plants were longer than those insects with water only, but shorter than those fed on mandarin. Among the non-host plants, D. citri performed better in coffee, followed by avocado and passion fruit plants. Our results indicate that the association of mandarin with avocado plant can be beneficial for Asian citrus psyllid management.