Assessing the efficiency of UAV for pesticide application in disease management of peanut crop.

BACKGROUND: Effective utilization of plant protection UAVs in peanut cultivation management necessitates a comprehensive grasp of how application volume rates and pesticides influence peanut leaf spot and rust control. This study aimed to compare the effects of application volume rates and pesticides on droplet deposition, disease, leaf retention rate and peanut yield. A T20 plant protection unmanned aerial vehicle (UAV) sprayer was used to apply four various pesticide doses. In comparison, a knapsack sprayer was used to spray with an application volume rate of 450 L ha-1. RESULTS: The results showed a significant difference in droplet deposition between the plant protection UAVs and the electric knapsack sprayer. In the pesticide treatment with an application volume rate of 15.0 L ha-1, there was no significant difference in the deposition on the peanut canopy of each pesticide treatment, but there was a significant difference in the deposition on the ground in the treatment with adding vegetable oil adjuvant. The treatment with added vegetable oil additives showed the worst performance. The treatment with an application volume rate of 22.5 L ha-1 showed the best performance, with the leaf spot control effect being only 0.3% lower than that of the electric knapsack sprayer. CONCLUSION: Plant protection UAV spraying is feasible to control peanut diseases. Considering the operational effectiveness of the plant protection UAV and application volume rate, it is recommended to use an application volume rate of 22.5 L ha-1 without adding vegetable oil adjuvants for field operations. © 2024 Society of Chemical Industry.

Herbivore-induced plant volatiles emitted by citrus in response to spider mite infestation can attract predatory mites.

Understanding the nutritional interplay among plants, pests, and natural enemies is essential for sustainable pest management. Enhancing the efficiency of natural enemies, such as Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) is critical, and exploiting herbivore-induced plant volatiles (HIPVs) offers a promising approach. However, N. californicus has rarely been reported to utilize HIPVs to improve their biological control capabilities. Our research revealed a significant difference in the diversity of volatile compounds detected in clean Citrus reticulata Blanco leaves compared to those in C. reticulata leaves infested with Panonychus citri (McGregor) (Acari: Tetranychidae), regardless of mite presence. This suggests that P. citri infestation induces a wide array of HIPVs in C. reticulata leaves. We conducted olfactory behavioral assays to evaluate the response of N. californicus to synthetic HIPVs. Results revealed that linalool (1.00 mg/mL), 2,2,4-trimethylpentane (10.0 mg/mL), undecylcyclohexane (1.00 mg/mL), and (+)-dibenzoyl-L-tartaric anhydride (10.0 mg/mL) significantly attracted N. californicus while pentadecanal (1.00 mg/mL) significantly deterred it. A 3-component blend of linalool, undecylcyclohexane, and (+)-dibenzoyl-L-tartaric anhydride was better than other combinations in attracting N. californicus. This combination provided the basis for developing an attractant for N. californicus, facilitating the rate of its dispersal to enhance its biological control of pests. Consequently, this research offers vital insights into improving the sustainable pest control potential of predatory mites.

Evaluation of the deposition and distribution of spray droplets in citrus orchards by plant protection drones.

Plant protection drone spraying technology is widely used to prevent and control crop diseases and pests due to its advantages of being unaffected by crop growth patterns and terrain restrictions, high operational efficiency, and low labor requirements. The operational parameters of plant protection drones significantly impact the distribution of spray droplets, thereby affecting pesticide utilization. In this study, a field experiment was conducted to determine the working modes of two representative plant protection drones and an electric backpack sprayer as a control to explore the characteristics of droplet deposition with different spray volumes in the citrus canopy. The results showed that the spraying volume significantly affected the number of droplets and the spray coverage. The number of droplets and the spray coverage area on the leaf surface were significantly increased by increasing the spray volume from 60 L/ha to 120 L/ha in plant protection drones. Particularly for the DJI T30, the mid-lower canopy showed a spray coverage increase of 52.5%. The droplet density demonstrated the most significant variations in the lower inner canopy, ranging from 18.7 droplets/cm2 to 41.7 droplets/cm2 by XAG V40. From the deposition distribution on fruit trees, the plant protection drones exhibit good penetration ability, as the droplets can achieve a relatively even distribution in different canopy layers of citrus trees. The droplet distribution uniformity inside the canopy is similar for XAG V40 and DJI T30, with a variation coefficient of approximately 50%-100%. Compared to the plant protection drones, the knapsack electric sprayer is suitable for pest and disease control in the mid-lower canopy, but they face challenges of insufficient deposition capability in the upper canopy and overall poor spray uniformity. The distribution of deposition determined in this study provides data support for the selection of spraying agents for fruit trees by plant protection drones and for the control of different pests and diseases.

Evaluating the effects of the route guidance variable message signs on driving behaviors-a driving simulation study.

OBJECTIVE: Route guidance variable message signs (VMS) are widely applied in traffic incident management on highways by providing real-time spatiotemporal guidance information. The improper panel of route guidance VMS is likely to diminish the compliance with guidance and induce risky driving behaviors, disrupting the traffic flow or even causing crashes. This article aims to investigate the effects of route guidance VMS on driving behaviors in three aspects, vehicle operation, visual perception, and route choice. METHODS: A driving simulation study with 32 participants was carried out to investigate the driving performance under four different VMS recognizing conditions: baseline (a typical guide sign) and three route guidance VMS panel schemes. RESULTS: Significant differences in average speed, speed fluctuation, average acceleration, and fixation proportion were found under various VMS recognition conditions. VMS3 had the least negative effects on vehicle operation and visual perception, and the compliance rate under VMS3 was the highest. The possible reasons are as follows: VMS3 has the simplified highway network structure and highlights the road directions with an eye-catching symbol, which can increase the comprehensibility of the guidance information while driving. CONCLUSIONS: Drivers need to take multiple actions under high-speed driving conditions while recognizing VMS, including reading the route guidance VMS, remaking route decisions, and operating the vehicle concurrently. Under such circumstances, the improper VMS panel would attract more drivers' attention and induce excessive risk compensatory behaviors, reducing drivers' compliance with guidance and situation awareness, and increasing crash risks. In addition, some VMS related traffic management strategies were proposed to improve safety and mobility of highways and further provide a basis for the formulation of related standards.

Control Efficacy and Deposition Characteristics of an Unmanned Aerial Spray System Low-Volume Application on Corn Fall Armyworm Spodoptera frugiperda.

As a major global pest, fall armyworm (FAW), Spodoptera frugiperda, invaded China in 2019, which has seriously threatened the safety of China's food production and raised widespread concerns. As a new low-volume application technology, an unmanned aerial spray system (UASS) is playing an important role in the control of FAW in China. However, the studies on the effect of the water application volume on the efficacy of FAW using UASS have been limited. In this study, Kromekote® cards were used to sample the deposition. The method of using a sampling pole and sampling leaf for the determination of deposition. Four water application volumes (7.5, 15.0, 22.5, and 30.0 L/ha) were evaluated with regard to the corn FAW control efficacy. A blank control was used as a comparison. The control efficacy was assessed at 1, 3, 7, and 14 days after treatment (DAT). The tested results showed that sampling methods have a significant effect on deposition results. The number of spray deposits and coverage on the sampling pole were 35 and 40% higher than those on the sampling leaves, respectively. The deposition and control efficacy gradually increased as the water application volume increased. The control efficacy at 14 DAT under different water application volumes was in the range of 59.4-85.4%. These data suggest that UASS spraying can be used to achieve a satisfying control of FAW, but the control efficacy of the water application volume of 30.0 and 22.5 L/ha did not differ significantly. Considering work efficiency, a water application volume of 22.5 L/ha is recommended for field operation.

Prediction of the potential distribution of the predatory mite Neoseiulus californicus (McGregor) in China under current and future climate scenarios.

Neoseiulus californicus is a predatory mite with a wide global distribution that can effectively control a variety of pest mites. In this study, MaxEnt was used to analyse the potential distribution of N. californicus in China and the BCC-CSM2-MR model was used to predict changes in the suitable areas for the mite from 2021 to 2100 under the scenarios of SSP126, SSP245 and SSP585. The results showed that (1) the average of area under curve value of the model was over 0.95, which demonstrated an excellent model accuracy. (2) Annual mean temperature (Bio1), precipitation of coldest quarter (Bio19), and precipitation of driest quarter (Bio17) were the main climatic variables that affected and controlled the potential distribution of N. californicus, with suitable ranges of 6.97-23.27 °C, 71.36-3924.8 mm, and 41.94-585.08 mm, respectively. (3) The suitable areas for N. californicus were mainly distributed in the southern half of China, with a total suitable area of 226.22 × 104 km2 in current. Under the future climate scenario, compared with the current scenario, lowly and moderately suitable areas of N. californicus increased, while highly suitable areas decreased. Therefore, it may be necessary to cultivate high-temperature resistant strains of N. californicus to adapt to future environmental changes.

Pregnancy and parenting experiences of women with twin-to-twin transfusion syndrome: a qualitative study.

BACKGROUND: Qualitative research can reflect the actual thoughts and experience of research subjects and can be used to explore the experiences of women presenting with twin-to-twin transfusion syndrome (TTTS) to facilitate the provision of targeted psychological support. METHODS: A semi-structured interview method was used to assess the pregnancy and parenting experiences of women with TTTS. Colaizzi method was used for data analysis. RESULTS: Eighteen women participated in the study. We found that women with TTTS during pregnancy experienced persistent worry about their children's health from the disease diagnosis to the subsequent parenting processes, even in case of minor changes in their children's health. The lack of an efficient referral process and health information increased their uncertainty about their children's health. CONCLUSION: In addition to the children's health, other difficulties encountered during pregnancy and parenting may aggravate the pressure. Clinicians in the first-visit hospital and foetal medicine centre should improve the referral process and establish a follow-up system to provide women with health information and psychological support.

Investigating the uniqueness of crash injury severity in freeway tunnels: A comparative study in Guizhou, China.

INTRODUCTION: With the rapid development of transportation infrastructures in precipitous areas, the mileage of freeway tunnels in China has been mounting during the past decade. Provided the semi-constrained space and the monotonous driving environment of freeway tunnels, safety concerns still remain. This study aims to investigate the uniqueness of the relationships between crash severity in freeway tunnels and various contributory factors. METHOD: The information of 10,081 crashes in the entire freeway network of Guizhou Province, China in 2018 is adopted, from which a subset of 591 crashes in tunnels is extracted. To address spatial variations across various road segments, a two-level binary logistic approach is applied to model crash severity in freeway tunnels. A similar model is also established for crash severity on general freeways as a benchmark. RESULTS: The uniqueness of crash severity in tunnels mainly includes three aspects: (a) the road-segment-level effects are quantifiable with the environmental factors for crash severity in tunnels, but only exist in the random effects for general freeways; (b) tunnel has a significantly higher propensity to cause severe injury in a crash than other locations of a freeway; and (c) different influential factors and levels of contributions are found to crash severity in tunnels compared with on general freeways. Factors including speed limit, tunnel length, truck involvement, rear-end crash, rainy and foggy weather and sequential crash have positive contributions to crash severity in freeway tunnels. Practical applications: Policy implications for traffic control and management are advised to improve traffic safety level in freeway tunnels.

Influential Factors Associated with Consecutive Crash Severity: A Two-Level Logistic Modeling Approach.

A consecutive crash series is composed by a primary crash and one or more subsequent secondary crashes that occur immediately within a certain distance. The crash mechanism of a consecutive crash series is distinctive, as it is different from common primary and secondary crashes mainly caused by queuing effects and chain-reaction crashes that involve multiple collisions in one crash. It commonly affects a large area of road space and possibly causes congestions and significant delays in evacuation and clearance. This study identified the influential factors determining the severity of primary and secondary crashes in a consecutive crash series. Basic, random-effects, random-parameters, and two-level binary logistic regression models were established based on crash data collected on the freeway network of Guizhou Province, China in 2018, of which 349 were identified as consecutive crashes. According to the model performance metrics, the two-level logistic model outperformed the other three models. On the crash level, double-vehicle primary crash had a negative association with the severity of secondary consecutive crashes, and the involvement of trucks in the secondary consecutive crash had a positive contribution to its crash severity. On a road segment level, speed limit, traffic volume, tunnel, and extreme weather conditions such as rainy and cloudy days had positive effects on consecutive crash severity, while the number of lanes was negatively associated with consecutive crash severity. Policy suggestions are made to alleviate the severity of consecutive crashes by reminding the drivers with real-time potential hazards of severe consecutive crashes and providing educative programs to specific groups of drivers.