Globally, Spodoptera frugiperda is a major threat to many important crops, including maize, rice, and cotton, causing significant economic damage. To control this invasive pest, environmentally friendly pest control techniques, including pheromone detection and identification of potential molecular targets to disrupt S. frugiperda mating communication, are needed. Female moths biosynthesize pheromones and emit them from the pheromone gland, which significantly depends on the intrinsic factors of the moth. Male S. frugiperda have a sophisticated olfactory circuit on their antennae that recognizes pheromone blends via olfactory receptor neurons (ORNs). With its potential to significantly modify the insect genome, CRISPR/Cas9 offers a revolutionary strategy to control this insect pest. The impairing physiological behaviors and disrupting the S. frugiperda volatile-sensing mechanism are the main potential applications of CRISPR/Ca9 explored in this review. Furthermore, the release of mutant S. frugiperda for their long-term persistence must be integral to the adoption of this technology. Looking forward, CRISPR/Cas9-based gene drive systems have the potential to synergistically target pheromone signaling pathways in S. frugiperda by disrupting pheromone receptors and key biosynthesis genes, thereby effectively blocking intraspecific communication and reproductive success. In conclusion, CRISPR/Cas9 provides an environmentally friendly and revolutionary platform for precise, targeted pest management in S. frugiperda.

The tomato leaf miner, Phthorimaea (Tuta) absoluta, Meyrick 1917 is recognized as a highly destructive pest, causing significant economic losses to crops in both greenhouse and open field environments across four continents: Asia, Africa, Europe, and South America. High genetic homogeneity among populations from various regions and countries indicates significant gene flow between P. absoluta populations, suggesting a lack of geographical barriers to dispersion. Furthermore, P. absoluta has developed resistance to insecticides due to target-site mutations or metabolic resistance, which enable the insect to withstand lethal doses of insecticides. To control this insect pest, the plant-mediated RNA interference (RNAi) is most promising host-induced gene silencing technique, utilized the plant’s machinery to express double-stranded (dsRNA), which triggers the RNAi pathway in P. absoluta. Due to thermal tolerance, the P. absoluta has increased its area of invasion by 600 km per year over 9 years. Female P. absoluta releases pheromones that are recognized by males with a sophisticated olfactory circuit on their antenna. Pheromone binding proteins (PBPs) play a crucial role in mate recognition and attraction, and their expression peaks during courtship, specifically around 6:00 a.m. Given its potential to significantly alter the insect genome, clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 (Cas9) offer a revolutionary strategy to control P. absoluta. Furthermore, this pest has developed remarkable adaptations to survive on unfavorable hosts by secreting specific proteins from its salivary glands that detoxify plant defenses. Insecticide resistance is likely the cause of field control failures of P. absoluta. Biological control, sex pheromone traps, and cultural control are the most promising approaches to address insecticide resistance resulting from these failures. Therefore, the implementation of integrated control programs and appropriate resistance management strategies is necessary to keep P. absoluta infestations under economic damage thresholds.

Priophorus fulvostigmatus, a species of leaf-cutter wasp, is an important leaf-feeding pest on strawberries. We investigated the effects of temperature and soil moisture content on key life cycle parameters of P. fulvostigmatus. The development time, survival, fecundity, and life table parameters of P. fulvostigmatus were observed at five temperatures. Pupal development and survival under five moisture contents (8%, 12%, 16%, 20%, and 24%) and four durations of water immersion (0, 1, 3, and 5 d) were recorded. P. fulvostigmatus could complete its life cycle at a constant temperature range of 16–28 °C. The duration of the immature stage first decreased and then increased with rising temperature, being longest at 16 °C and shortest at 25 °C. Female longevity and female fecundity did not differ between the temperature range of 16–25 °C. However, survival rates at all developmental stages decreased with increasing temperature. At 28 °C, both fecundity and survival rates of P. fulvostigmatus were significantly reduced compared to other temperatures. Compared with that at the constant temperature of 22 °C, the developmental duration of each stage was similar at a fluctuating temperature of 22 °C. The number of eggs laid per female, the longevity of male adults, and the eclosion rate were all significantly reduced. The net reproductive rate (R₀) under constant temperature conditions was significantly higher than under fluctuating temperature conditions, and the mean generation period (T), intrinsic rate of increase (r), and finite rate of increase (λ) differed significantly. The soil moisture content significantly impacted the pupation and eclosion of P. fulvostigmatus. Differences in soil moisture content had no significant effect on the duration of development; a moisture content of 8–16% was more suitable for their pupation and eclosion. Pupal development differed significantly between different periods of water immersion after the mature larvae were immersed in the soil. The longer the larvae remained in the soil, the lower their emergence rate after immersion. Thus, environmental temperature affected the growth, reproduction, and survival of P. fulvostigmatus. The optimal soil moisture for pupation of mature larvae was 12% to 16%. After the larvae were immersed in soil, the emergence rate was significantly reduced. These findings expand our understanding of the biological characteristics of P. fulvostigmatus and can facilitate the development of prevention and control strategies.

Globally, Trichogramma Westwood (Hymenoptera: Trichogrammatidae) is known as the most effective biological control agent due to its ability to parasitize insect pest eggs. However, identifying an appropriate host is vital for Trichogramma to prosper. Therefore, this study delves into the complex role of semiochemicals in shaping the host-seeking behavior of Trichogramma parasitoids, with a particular focus on their responses to both plant-derived and host-derived cues. The mechanism of semiochemical reception in Trichogramma wasps relies on a highly specialized, sensitive olfactory and gustatory system to locate host eggs and mates. Semiochemicals, which mediate ecological interactions, have been identified as pivotal in influencing the parasitic efficiency of Trichogramma species. Trichogramma’s host-seeking behavior is influenced not solely by ovipositional cues but also by the intrinsic physical attributes of Lepidopteran hosts, such as the scales on the wings and abdomen, which emit semiochemicals capable of eliciting positive chemotactic responses, thereby guiding parasitoids toward optimal sites for oviposition. Furthermore, the interplay between insect-derived and plant-derived chemical cues exhibits a synergistic effect, collectively enhancing the chemotactic attraction of Trichogramma, thereby fine-tuning its host-seeking behavior with greater precision and specificity. This study further underscores Trichogramma’s innate behavioral ability to discriminate between host eggs of varying developmental stages, facilitating the precise identification and selection of the most suitable host for parasitization. Age and experience both make Trichogramma more selective of hosts, but younger parasitoids may take a broader approach to host selection due to their greater life expectancy. Furthermore, the removal of these cues affects their host localization and learning abilities. Associative learning enables Trichogramma to exhibit flexible behaviors, providing them with a selective advantage; allows them to explore various hosts; and reduces environmental uncertainty. Plant structure, host density, and host age are the key factors that significantly influence the foraging and parasitism of Trichogramma. The searching speed of this parasitoid is significantly influenced by temperature. Heat stress increases VOC emissions in plants such as potato via stomatal opening, reducing herbivore attraction and enhancing parasitoid recruitment. Furthermore, air pollution, including CO₂, O₃, and NOx, impairs parasitoid efficiency by disrupting volatile-mediated host location and reducing biological control performance. Trichogramma wasps are generally effective biological control agents, but their success depends on the species used, target pest, crop, release density, and field conditions. Overall, species such as T. ostriniae, T. japonicum, and T. leucaniae show the strongest performance in several crops by increasing parasitism, reducing pest damage, and improving yield. This study highlights the successful integration of semiochemical cues in pest management programs and the effective utilization of Trichogramma in conjunction with entomopathogenic bacteria to control Lepidopteran pests. This approach contributes to the development of more effective pest management strategies, thereby promoting agricultural sustainability.

Interspecific competition among parasitoids significantly influences the efficiency and stability of biological control programs; however, competitive interactions occurring inside host eggs remain poorly understood because conventional approaches mainly rely on adult emergence outcomes. This study investigated the temporal dynamics of competition between Trichogramma dendrolimi and Trichogramma ostriniae in two host systems, the eggs of Ostrinia furnacalis, the Asian corn borer, and Corcyra cephalonica, the rice moth, using species-specific molecular detection. Sequential parasitization assays were performed with reversed introduction sequences (T. dendrolimi–T. ostriniae and T. ostriniae–T. dendrolimi), followed by molecular identification of parasitoid persistence at eight developmental time points after parasitization. Three detection states were identified: T. dendrolimi-only, T. ostriniae-only, and simultaneous T. dendrolimi + T. ostriniae detection. Results demonstrated that developmental progression was the strongest determinant of parasitoid detection transitions. Oviposition sequence showed no significant overall effect, although descriptive differences between introduction sequences were observed within individual host species. Early developmental stages were characterized by simultaneous detection of both parasitoids, indicating initial coexistence within host eggs. However, simultaneous detection rapidly declined, followed by host-specific dominance patterns. In O. furnacalis eggs, T. ostriniae became the predominant molecular signal during later development, exceeding 75% detection frequency, whereas T. dendrolimi remained comparatively lower. Conversely, in C. cephalonica eggs, T. dendrolimi showed greater molecular persistence, reaching approximately 60% detection frequency during later developmental stages. Host species significantly influenced molecular detection outcomes, demonstrating host-associated differences in parasitoid molecular persistence. These findings reveal that parasitoid competition is a dynamic developmental process rather than a simple outcome of emergence success and highlight the importance of host-dependent interactions in optimizing Trichogramma-based biological control strategies.

This study investigated whether carbohydrate source and the persistence of nutrient availability influence the life-history and reproductive performance of Trichogramma chilonis. Seven experimental treatments were evaluated: continuous supply of 20% honey–water (HWC), one-time supply of 20% honey–water with the nutrient source retained throughout the experiment (HW1C), one-time supply of 20% honey–water followed by removal of the nutrient source on Day 2 (HW1), continuous supply of 20% sucrose (SWC), one-time supply of 20% sucrose with the nutrient source retained throughout the experiment (SW1C), one-time supply of 20% sucrose followed by removal of the nutrient source on Day 2 (SW1), and a water-only control (CK). Unlike previous studies that primarily compared carbohydrate types or carbohydrate-fed and unfed parasitoids, the present study specifically assessed the importance of persistent nutrient access. Nutrient-supply treatments significantly increased adult longevity and lifetime parasitism capacity compared with the water-only control. SW1C, SWC, HWC, and HW1C showed statistically comparable longevity and lifetime parasitism capacity and performed better than treatments in which the nutrient source was removed and the water-only control. Daily parasitism was highest during the early adult period and declined with age, although nutrient-fed females maintained parasitism for a longer period. Female progeny ratio varied among experimental treatments, while offspring emergence remained high and statistically similar across the experimental treatments, ranging from approximately 85% to 89%. Overall, honey–water and sucrose diets improved the adult performance of T. chilonis without reducing offspring viability, supporting their use in mass-rearing and biological-control programs.