Search

Sugarcane aphid, Melanaphis sacchari Zehntner, is an important piercing-sucking pest on sorghum, sugarcane, and other graminaceous crops, not only damaging host plants by direct feeding, but also transmitting plant viruses that is detrimental to crop production. To evaluate the performance of two native parasitoid species, Aphelinus varipes (Förster) and Lysiphlebia japonica (Ashmead), on M. sacchari, the age stage, two-sex life table analysis was conducted to evaluate the demographic parameters of the two species. The results showed that the two parasitoids parasitized M. sacchari and completed their whole life history. The number of eggs laid by A. varipes (F: 209.49 offspring/female) and the number of oviposition days (Od: 14.18 d) were significantly higher than those of L. japonica (F: 87.47 offspring/female, Od: 3.36 d). Moreover, the intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (R0) of A. varipes (r: 0.3746 d-1, λ: 1.4160 d-1, R0: 113.125 offspring/individual) were significantly higher for A. varipes than those of L. japonica (r: 0.3386 d-1, λ: 1.4030 d-1, R0: 48.092 offspring/individual). In addition, the net killing rate (C0) of A. varipes was 119.57 (eggs/female), which was significantly higher than that of L. japonica (53.34 eggs/female). These findings suggested that A. varipes had higher performance with promising potential as biological control agent for sugarcane aphid.

Abstract Background Telenomus remus Nixon is an important egg parasitoid of Spodoptera spp. pests and, as such, has potential as a biological control agent. Spodoptera litura (Fabricius) is a significant pest of many economically important crops worldwide. This study was conducted to evaluate the demographic parameters and functional response of T. remus on the S. litura eggs. Results T. remus can lay 186.90 eggs/female in the lifetime, adult preoviposition period was 0 days, total preoviposition period was 10.03 days, and the ratio of female and male offspring was 0.495 and 0.421, respectively. In addition, most females emerged from 24 h-old eggs, whereas most males emerged from 48 h-old eggs. The intrinsic rate of increase, finite rate of increase, net reproductive rate, mean generation time, and population doubling time were 0.3506 d–1 1.4199 d–1 92.45 offspring/individua, 12.91 days and 1.98 days, respectively. The net killing rate of T. remus on S. litura was 101.49 eggs/female, indicating the high capacity of T. remus to parasitize S. litura eggs. Moreover, the higher the egg density, the higher the parasitism rate by female T. remus, although there was a trend of parasitism stabilization at an egg density of 100, indicating a type II functional response curve for this parasitoid. Conclusion Overall, these findings suggest that T. remus can be efficiently reared on S. litura eggs and shows potential as biocontrol agent for this economically important pest species.

Abstract Background Pink stem borer, Sesamia inferens (Walker), a major rice pest, has rarely been reported to cause serious damage to sorghum in China. During a survey of insect pests in glutinous sorghum for Chinese liquor production areas in Guizhou Province, it was found that S. inferens has caused serious damage to local sorghum in recent years. Methods In this context, we assessed the adaptation of S. inferens to three gramineous crop host plants (maize, rice and sorghum) based on age-stage, two-sex life table theory. Results Sesamia inferens had the highest development time, survival rate and total longevity on rice, followed by on sorghum and maize. There was no significant difference in intrinsic rate of increase and finite rate of increase among maize (r = 0.0702 day−1, λ = 1.0727 day−1), sorghum (r = 0.0681 day−1, λ = 1.0705 day−1) and rice (r = 0.0645 day−1, λ = 1.0666 day−1), but the mean generation period (T) was significantly higher for populations reared on rice (53.84 days) than on sorghum (49.53 days) and maize (47.31 days). Conclusions The results of our study indicate that S. inferens was able to complete the full developmental cycle on all three host plants. This study further supports that glutinous sorghum is an adaptable host plant for S. inferens.

The biting midge, Forcipomyia taiwana (Shiraki) (Diptera: Ceratopogonidae), can cause severe allergic reactions. It can pass through typical mosquito netting, so repellents are an important control measure against it. This project sought to identify spatial repellents from plants traditionally used by Taiwanese Aboriginal peoples as insect repellents. Fresh plant leaves were collected, frozen, and powdered, and essential oils extracted using hexane then ethyl acetate as solvents. Some commercial oils were also used. The extracts were tested against lab-reared F. taiwana using a Y-tube olfactometer. The composition of the extracts was identified using gas-chromatography mass-spectrometry (GC-MS). Commercial citronella, lavender, and Formosan cypress oils were effective repellents, as were lab-made capillary wormwood and camphor oils. Knockdown was detected in commercial clove leaf, rosemary, common wormwood, and cajuput oils. The oil composition data is the first for many of the Taiwanese plants, many of which contained repellent compounds like caryophyllene, α-pinene, and germacrene D. The results agreed with previous studies on the effects of some plants but differed on others, possibly due differences in plant chemotype, extraction method, and oil concentrations. Key Policy Highlights Botanical oils may have some effect as personal repellents against Forcipomyia taiwana. Commercially available oils show the most promise. Certain endangered trees show promise as sources of repellents, so their conservation should be prioritized.

Objective: This study presents a novel odontoid parameter, the odontoid incidence (OI), to examine the correlation between OI on preoperative cervical sagittal radiographs and 2-year clinical outcomes following short-segment anterior cervical discectomy and fusion (ACDF) in patients with cervical spondylotic myelopathy (CSM). Methods: A retrospective analysis of the clinical data of 87 patients with CSM who underwent ACDF surgery from January 2018 to December 2023 was conducted. The patients were categorized into a larger OI group (44 patients, OI > 12.62°) and a smaller OI group (43 patients, OI ≤ 12.62°) on the basis of the median cervical sagittal OI prior to surgery. The postoperative follow-up duration was 2 years. Cervical sagittal parameters were assessed on lateral cervical spine radiographs both preoperatively and postoperatively. Additionally, the Japanese Orthopedic Association (JOA), neck disability index (NDI), and visual analog scale (VAS) scores were documented for each patient before surgery and at the final 2-year postoperative follow-up. Results: Compared with those in the preoperative period, the T1 slope, C2‒C7 Cobb angle, sagittal segmental angle (SSA), and C0‒C2 Cobb angle significantly improved in 87 patients with cervical spondylosis (P < 0.05). At the 2-year postoperative follow-up, all patients exhibited significant improvements in JOA, NDI, and VAS scores compared with the preoperative values (P < 0.05). No statistically significant difference was observed in the preoperative or baseline data between the larger OI group and the smaller OI group (P > 0.05); however, a statistically significant difference was noted in the postoperative SSA between the two groups (P < 0.05). A statistically significant difference was observed in the VAS score and NDI score at the final follow-up between the two groups (P < 0.05), as well as in the improvement in the JOA score and VAS score (preoperative score minus the final follow-up score), between the two groups (P < 0.05). The results of the Pearson correlation analysis indicated a negative correlation between the preoperative OI score and the VAS and NDI scores at the final postoperative follow-up (P = 0.012, r = − 0.268) (P = 0.028, r = − 0.236). Conclusion: In ACDF, the preoperative OI of patients with CSM was negatively correlated with the VAS and NDI scores at the final postoperative follow-up; Larger preoperative OI corresponded to lower VAS and NDI scores at the final follow-up, leading to comparatively improved 2-year clinical outcomes. [ABSTRACT FROM AUTHOR]

The convergence of carbapenem-resistance and hypervirulence genes in Klebsiella pneumoniae has led to the emergence of highly drug-resistant superbugs capable of causing invasive disease. We analyzed 556 carbapenem-resistant K. pneumoniae isolates from patients in Singapore hospitals during 2010–2015 and discovered 18 isolates from 7 patients also harbored hypervirulence features. All isolates contained a closely related plasmid (pKPC2) harboring blaKPC-2, a K. pneumoniae carbapenemase gene, and had a hypervirulent background of capsular serotypes K1, K2, and K20. In total, 5 of 7 first patient isolates were hypermucoviscous, and 6 were virulent in mice. The pKPC2 was highly transmissible and remarkably stable, maintained in bacteria within a patient with few changes for months in the absence of antimicrobial drug selection pressure. Intrapatient isolates were also able to acquire additional antimicrobial drug resistance genes when inside human bodies. Our results highlight the potential spread of carbapenem-resistant hypervirulent K. pneumoniae in Singapore.

The initial processing of Citrus Reticulata 'Chachi' involves peeling as a crucial step. Currently, there is some semi-automatic peeling equipment available. However, due to the requirement of adjusting the orientation of Citrus Reticulata 'Chachi' to ensure the stem (or navel) is facing upwards before peeling and because the peeling process must retain the stem as a marker for fresh fruit picking, the loading of Citrus Reticulata 'Chachi' for peeling still solely relies on manual operation, resulting in low efficiency and poor standardization. With the rapid growth of the pericarp of the Citrus Reticulata 'Chachi' industry, semi-automatic processing equipment is no longer able to meet production demands. The loading issue before peeling Citrus Reticulata 'Chachi' is a complex hand–eye coordination problem. In response to this issue, this paper proposes a novel Citrus Reticulata 'Chachi' orientation adjustment mechanism (COAM). This mechanism utilizes frictional force to adjust the orientation of Citrus Reticulata 'Chachi'. First, the conceptual design and kinematic modelling analysis of the mechanism were conducted. Next, the omnidirectional friction-driven wheels were optimized in design. Subsequently, a prototype was manufactured and assembled to conduct validation tests on its open-loop motion performance. Finally, a visual feedback-guided algorithm was introduced to complement the kinematic model, enabling the automatic and rapid adjustment of Citrus Reticulata 'Chachi' orientation. The experimental results indicate that the COAM designed in this study can effectively and rapidly adjust the orientation of Citrus Reticulata 'Chachi' fruits of different sizes and shapes. It demonstrates strong adaptability, and under visual feedback guidance, the orientation adjustment error is less than 10% of the fruit's diameter. This meets the requirements for automated production in the initial processing of Citrus Reticulata 'Chachi'. The research presented in this paper also provides new insights for the orientation adjustment and loading of similar spherical fruits. [ABSTRACT FROM AUTHOR]