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Megalurothrips usitatus (Bagrall) is one of the most important pests of cowpea, Vigna unguiculata (Linn.) Walp in South China. Four Orius species, including Orius minutus (L.), Orius nagaii (Yasunaga), Orius sauteri (Poppius), and Orius strigicollis (Poppius), have been commercially produced and widely used as natural enemies of pests in China. In this study, we evaluated the control efficiency of these Orius species on M. usitatus in tropical Hainan Province, China, by recording the survival rates, developmental times, and predation effects in laboratory and semi-field conditions. Laboratory experiments showed that all these 4 Orius species preyed on M. usitatus under the experimental temperatures (25, 30, and 35 °C), and O. strigicollis exhibited the highest survival rate and predation effect. Semi-field cage experiments showed that the control effect of 4 Orius species on M. usitatus was significantly higher than that under normal chemical control, with O. strigicollis having the highest effect. Greenhouse experiments in Hainan Province, China, confirmed that O. strigicollis had a significant control effect on M. usitatus. Our study indicated that O. strigicollis has a significant potential for the control of M. usitatus in cowpea fields in southern China.

Thrips of the subtropical genus Scirtothrips are emerging as important pests in several crops. Scirtothrips dorsalis has been increasingly invading new areas outside of its native region of South and East Asia causing economic damage to several crops. Scirtothrips inermis is another polyphagous species with worldwide distribution. Both species are polyphagous, and in recent years have emerged as key pests in strawberry. In this study, we first evaluated the predation and oviposition rate of commercially available phytoseiid predatory mites Amblyseius swirskii, Amblydromalus limonicus, Transeius montdorensis, and Neoseiulus cucumeris on larval stages of both Scirtothrips species, and oviposition rates of predatory mites on the supplementary food source Artemia franciscana cysts were also assessed. Predatory mites equally accepted both thrips species as prey and showed stable oviposition rates on these diets. Amblyseius swirskii and A. limonicus were the most voracious, also exhibiting the highest oviposition rate of the predators tested. We further evaluated the biological control potential of predatory mites and anthocorid predators Orius laevigatus and Orius limbatus in a greenhouse experiment. Predators were released preventively and supported with Artemia cysts before the introduction of S. inermis . Both Orius predators achieved good control of the pest, with O. limbatus developing higher numbers than O. laevigatus . Regarding phytoseiids, A. swirskii and A. limonicus both controlled the pest and built higher populations than T. montdorensis and N. cucumeris . Our results show that a preventive strategy based on phytoseiid or anthocorid predators in strawberry can be effective in suppressing S. inermis .

We thank Julio Bernal for kindly sharing the D. maidis colony, Hao Xu for help with olfactometer assays, Gregory Röder for help with the GC-MS analyses, and Angela Köhler for maintaining the Dalbulus colony. A.A. was funded with an FPU scholarship and a visiting grant to FARCE laboratory from the Ministerio de Educación. The work was partially funded by the Spanish Government project AGL2011-23996.

The polyphagous predator Orius species is a dominant predator of thrips, mites, and aphids. Orius laevigatus (Fieber) is a well-known commercialized and effective biological control agent, whereas Orius minutus (L.) distributed widely over the world has not been commercialized. To assess potentials of developing O. minutus as a commercial biological control agent, we compared the biological parameters of O. minutus with O. laevigatus when reared on mixed stages of Tetranychus urticae Koch at 27.5°C. Nymphal development of O. laevigatus was shorter (11.30 d) than that of O. minutus (12.25 d), but there was no significant difference in survivorship between the two species. Also, no significant difference was found in either the preoviposition or oviposition periods, lifetime fecundity, or longevity between the two species. However, O. minutus eggs had a higher hatch rate (0.77) than O. laevigatus (0.71). In life table analysis, no difference was found in any parameters, i.e., R0, rm, λ, T, and DT, between O. laevigatus and O. minutus in two-tailed t-tests. In a predation bioassay, O. minutus consumed 1.39 times more adult T. urticae in 24 h than did O. laevigatus, although the predation rate on T. urticae eggs was similar between the two species. These results suggest that O. minutus native to Korea could be developed as a biological control agent against T. urticae.

A two-sex life table is a useful tool for studying the fitness of predators. Previous studies of Orius strigicollis Poppius (Heteroptera: Anthocoridae) fitness have not been done on Pectinophora gossypiella (Lepidoptera: Gelechiidae) using a two-sex life table tool. This study reports the fitness of the minute predatory flower bug, O. strigicollis when feeding on the cotton pest P. gossypiella using a two-sex life table tool. Different densities (5, 10, and 15 eggs) of P. gossypiella eggs were used to calculate the feeding capacity and fitness of O. strigicollis in the laboratory at 28 °C ± 1, 75 ± 5% RH and 16:8 (L:D). The results concluded that O. strigicollis is an efficient predator of P. gossypiella. The maximum growth capacity of the predatory bug O. strigicollis was attained when it was fed on 10 and 15 P. gossypiella eggs. Furthermore, shorter generation and development time were also observed in the case of 15 eggs of P. gossypiella. These results suggest that O. strigicollis has considerable predatory potential and prefers feeding on P. gossypiella eggs than on the first instar larvae at the fourth instar or the female stage. Although the field potential of O. strigicollis is still unknown, this study will support future investigations in terms of field applications.

The western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is a key pest of sweet pepper cultivation, where it causes feeding damage, excretes phytotoxic substances, and transmits important viruses. Control with chemical insecticides often is ineffective because endophytic oviposition and the cryptic habits of the pest provide protection. In Uruguay, the biological control program of this pest in sweet pepper crops is at risk due to the low settlement rate and high dispersal of releases of predator Orius insidiosus (Say) (Hemiptera: Anthocoridae). Previous studies have ruled out an antibiosis effect as the cause of dispersal; therefore, we hypothesized antixenosis (non-preference) for the sweet pepper plants as the cause of poor biological control by O. insidiosus. The effect of olfactory stimuli from different structures of strawberry, corn, and sweet pepper plants (lamuyo and blocky type) on the behavior of O. insidiosus was evaluated in olfactometry and free-choice cage experiments. Since Orius tristicolor (White) (Hemiptera: Anthocoridae) occurs naturally in the area, it was included also in the study with the aim of assessing whether there are differences in behavior between the species. Orius tristicolor may act as a complementary biocontrol agent or competitor on sweet pepper. Y-tube experiments showed no preference for plant volatiles in any combination, and response to volatile stimuli generally was poor. However, in the free-choice cage experiment, females of both species of Orius preferred the flowering strawberry plants over the flowering sweet pepper plants, which could explain the low establishment of O. insidiosus when released on pepper with neighboring strawberry fields. Given that horticultural greenhouses in Uruguay and in many other countries are open, this information can be very useful in designing the spatial and temporal management of different crops on a production field, which enhances the effectiveness of these predatory species.

Orius strigicollis (Poppius) has been commonly released to control minute pests due to its remarkable foraging and predation ability. Despite decades long history of mass-rearing using eggs of Cadra cautella Walker (Lepidoptera: Pyralidae) as food, the cost of this food impeded the predator's marketing potential. Finding cost-effective artificial diets for mass rearing programs is, therefore, the key to promote the use of this generalist predator in practice.The aim of this study was to explore suitability of alternative diets for mass rearing of this predator, using the age-stage, two-sex life table. Eight recipes of artificial diets were initially screened, and the candidate diets were subsequently evaluated using the population parameters of O. strigicollis.The highest intrinsic rate of increase was found in the O. strigicollis fed on the meridic combined Diet 1, where nymphs and adults were fed different diets. However, the intensive period of oviposition by females reared on oligidic Diet O3 contributed to the shorter rearing period (42 d) and lower rearing cost than that on combined Diet 1 (60 d). Besides, with the harvest rate of 0.919, the minimal population size of 10,774 individuals with a stable age-stage distribution was needed for daily harvesting 1,000 third instars of O. strigicollis reared on Diet O3 at the rearing cost of 0.295 NTD (newTaiwanese dollar) per nymph.Thus, Diet O3 was determined to be the most cost-effective recipe for the mass-rearing of O. strigicollis among those used in this study.

Zoophytophagous bugs feed on both arthropod pests and plants, and can survive or reproduce solely on particular plants. This characteristic ensures their survival when released as natural enemies when the density of target pests is low. When using zoophytophagous bugs, exotic species or strains should be avoided as biological control agents due to their ecological risks. This study reviews investigations of indigenous Orius species and indigenous strains of N. tenuis and their exploitations as biological control agents in Japan. Orius strigicollis , which can reproduce under short-day conditions, is recommended for augmentative biological control in greenhouses. Orius sauteri , the predominant and most abundant species in the field, is not recommended for releases in greenhouses because it enters diapause under short-day conditions. However, this species can be used for conservation biological control in the field, where the bug can be preserved through the use of selective pesticides or by conserving companion plants. Violet light illumination is a promising tool to manipulate the movement of this species in the field. Nesidiocoris tenuis occurs only in the southern region of Japan, and its density in the field is low. This bug can be used for augmentative biological control in greenhouses. It can reproduce on specific plants, including Sesamum indicum , Cleome hassleriana , Verbena  ×  hybrida , and Scaevola aemula . These plants can be used as banker plants to improve the establishment and reproduction of N . tenuis in greenhouses. Indigenous Orius species and Nesidiocoris tenuis are promising biological control agents in Japan.

The performance of four aphid predators, Hippodamia convergens Guerin-Meneville, Coleomegilla maculata DeGeer, Chrysopeda carnea Stephens and Orius insidiosus Say was compared on three prey species: Schizaphis graminum Rondani, Melanaphis sacchari (Zehntner), and Ephestiakuehniella Zeller eggs. Species predatory in both life stages (all except Ch, carnea) were reared on E. kuehniella eggs and switched to aphid prey for assessment of reproduction. Differences were greater between the E. kuehniella and aphid diets than between the two aphid species. Juvenile survival was high for all predators on all prey, except for O.insidiosus, which had survival on E. kuehniella >S. graminum > M. sacchari. The fastest development of Ch, carnea and O.insidiosus was obtained on E. kuehniella, whereas H. convergens developed fastest on S. graminum, and C. maculata did not differ among diets. S. graminum also yielded the largest H. convergens adults, whereas the largest adults of other predators were obtained on E. kuehniella. Female fecundity and egg viability were similarly high on both aphid diets for H. convergens and C. maculata, whereas, on E. kuehniella, 50% of the former entered reproductive diapause and the latter species had reduced fecundity. Reproductive success of Ch,carnea was S. graminum =M. sacchari >E. kuehniella, but it was similar among treatments for O.insidiosus, although female infertility ranged from 25 to 37.5%. We concluded that all the predators studied are preadapted to utilize sugarcane aphid as prey and have excellent potential to provide sustainable biological control of this newly invasive pest.

Plant volatiles are critical mediators of insect-plant interactions, guiding natural enemies to specific habitats and prey. The flower bug, Ghauri (Hemiptera: Anthocoridae), is a generalist predator that exhibits a specialized ecological association with the weed L. (Caryophyllales: Amaranthaceae), utilizing the plant as a primary floral niche in Hainan Island. In this study, the attractiveness of floral volatiles to was confirmed using a Y-tube olfactometer. Solid-phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS) was utilized to identify six compounds in the floral volatiles: 1,3-diethenylbenzene, trans-cinnamaldehyde, β-bisabolene, methyl salicylate, 3-ethylbenzaldehyde, and nonanal. Electroantennogram (EAG) assays revealed that antennae showed significant physiological responses to these compounds, and the EAG relative values were positively correlated with concentration gradients. Furthermore, exhibited significant orientation responses to 1,3-diethenylbenzene, trans-cinnamaldehyde, β-bisabolene, and methyl salicylate, whereas no behavioral response was observed for 3-ethylbenzaldehyde or nonanal. Further tests revealed that β-bisabolene elicited the highest attractiveness, comparable to a synthetic blend formulated to mimic the natural release ratio of the active semiochemicals. These findings reveal the hidden chemical cues mediating the interaction between a predator and its preferred habitat. Understanding this mechanism not only helps explain insect adaptation but also offers new strategies for using these plant volatiles to influence the behavior of this specific predator, potentially enhancing its targeted recruitment in agroecosystems.