Prediction of the potential distribution area of Spodoptera frugiperda and its parasitic wasp, Trichogramma pretiosum.

Spodoptera frugiperda is a migratory agricultural pest with fast-spreading speed, long migration distance, and wide host range, which seriously threatens the safety of economic crops. To predict the trends of S. frugiperda and its parasitoid wasp Trichogramma pretiosum in their habitats under current and future climatic conditions, based on MaxEnt model and geographic distribution data of their historical occurrence, we project the feasibility of introducing T. pretiosum to control S. frugiperda by evaluating on their potential global distribution. The results show that, under the current greenhouse gas concentration, the potential distribution area of S. frugiperda is concentrated in 50° N-30° S, with a total area of 1.74 × 106 km2 , and the potential distribution area of T. pretiosum in the whole world is 2.91 × 106 km2 . The suitable areas of T. pretiosum cover almost all the suitable areas of S. frugiperda, which indicates that T. pretiosum can be introduced to control S. frugiperda. The results of this study can provide a theoretical basis for the monitoring and early warning of S. frugiperda and the use of T. pretiosum to control S. frugiperda.

Potential global distribution area projections of the aphid Lipaphis erysimi and its predator Eupeodes corollae in the context of climate change.

Climate change affects the population distribution of pests and their natural enemies, and predicting these effects is necessary for pest monitoring and green control. Lipaphis erysimi is an important vegetable pest, and its natural enemy, the Eupeodes corollae Fabricius has a strong predatory effect on the L. erysimi. To assess the spread trends of L. erysimi and its natural enemy, the hoverfly, E. corollae under current (1970-2000) and future climates (2041-2060), based on the MaxEnt model, this paper uses data on the geographical distribution of the historical occurrence of L. erysimi and E. corollae to speculate on their potential distribution areas worldwide and analyze the key environmental factors affecting the survival and spread of both. The results showed that the Representative Concentration Pathway (RCP) 2.6 and RCP4.5 climatic conditions are favorable for the spread of L. erysimi, the RCP8.5 climatic conditions are unfavorable for the spread of L. erysimi, and all three future climatic conditions are unfavorable for the spread of E. corollae. The highest fitness of L. erysimi was found at the annual average temperature of 18 °C and the annual average precipitation of 900 mm, while the highest fitness of E. corollae was found at the annual average temperature of 10 °C and the lowest temperature in the coldest month of 0 °C. This study can provide a reference basis for monitoring and early warning and biological control of L. erysimi.

Optimization of Sensors Data Transmission Paths for Pest Monitoring Based on Intelligent Algorithms.

The harm of agricultural pests presents a remarkable effect on the quality and safety of edible farm products and the monitoring and identification of agricultural pests based on the Internet of Things (IoT) produce a large amount of data to be transmitted. To achieve efficient and real-time transmission of the sensors' data for pest monitoring, this paper selects 235 geographic coordinates of agricultural pest monitoring points and uses genetic algorithm (GA), particle swarm optimization (PSO), and simulated annealing (SA) to optimize the data transmission paths of sensors. The three intelligent algorithms are simulated by MATLAB software. The results show that the optimized path based on PSO can make the shortest time used for transmitting data, and its corresponding minimum time is 4.868012 s. This study can provide a reference for improving the transmission efficiency of agricultural pest monitoring data, provide a guarantee for developing real-time and effective pest control strategies, and further reduce the threat of pest damage to the safety of farm products.

Function of Vitellogenin receptor gene in reproductive regulation of Zeugodacus cucurbitae (Coquillett) after short-term high-temperature treatment.

Climate change has increased the frequency of extreme heat events. Zeugodacus cucurbitae (Coquillett) is an important tropical pest that typically changes its reproductive strategies in response to extremely high temperatures. Newly emerged adults of three consecutive generations (F1, F2, and F3) of Z. cucurbitae (Coquillett) were exposed to 25°C, 33°C, 37°C, 41°C, and 45°C treatments for 1 h to clarify the effects of short-term high temperatures on its reproduction. The influence of these temperatures on reproduction was evaluated using indicators, such as egg number. Newly emerged adults were exposed to 25°C and 45°C treatments for 1 h, and the expression of Vitellogenin receptor (VgR) gene in females was interfered with siRNA, and silencing efficiency of RNAi was evaluated. Results showed that short-term high temperatures, except for F1 treated at 45°C for 1 h to stimulate oviposition, exert a general adverse effect on the reproduction of Z. cucurbitae (Coquillett). All F3 died after the 45°C treatment for 1 h. Silencing of the VgR gene resulted in the significant downregulation of VgR gene expression at both 24 and 72 h. The egg number, oviposition days, and hatchability of eggs were significantly lower than those of other treatment groups after interference, and the inhibition effect of egg number was the most evident, with a decrease of 88.4% and 95.2% at 25°C and 45°C, respectively, compared with that of the Control Check (CK). Ovarian development speed and diameter were also significantly lower than those of other treatment groups after the interference. The results of this study can provide a theoretical reference for the integrated control of Z. cucurbitae (Coquillett) during high-temperature seasons.

Comparative Genomic-Based Study of Reproduction-Related Genes in Three Fruit Fly Species.

Zeugodacus cucurbitae (Coquillett), Bactrocera dorsalis (Hendel), and Ceratitis capitata (Wiedemann) are important pests of fruit and vegetable crops and are difficult to control because of their rapid reproduction rate and egg production. To investigate the key genes regulating reproduction in three fruit fly species, we selected genomic information of three fruit fly species, screened specific genes and single-copy homolog genes, and performed KEGG and GO enrichment analysis on specific genes and single-copy homolog genes of the strong positive select (SP); the results showed that Z. cucurbitae (Coquillett), B. dorsalis (Hendel), and C. capitata (Wiedemann) had seven, 11, and one Vitellogenin-related genes, respectively; Z. cucurbitae (Coquillett) had 84 specific genes enriched in immune system-related pathways; B. dorsalis (Hendel) had 1,121 specific genes enriched in signaling pathways related to cell growth and differentiation; C. capitata (Wiedemann) had 42 specific genes enriched in the degradation and metabolism pathways of exogenous organisms; Z. cucurbitae (Coquillett) may have a stronger immune system; B. dorsalis (Hendel) has a faster developmental and reproductive rate; and C. capitata (Wiedemann) has a higher detoxification capacity. Only one SP single-copy homolog gene (gene name: very long-chain specific acyl-CoA dehydrogenase, mitochondrial) is enriched in the fatty acid metabolic pathway in both Z. cucurbitae (Coquillett) and B. dorsalis (Hendel) as well as in Z. cucurbitae (Coquillett) and C. capitata (Wiedemann). This study provides a molecular basis for studying the reproductive mechanisms of three fruit fly species and provides a scientific basis for developing effective control strategies for fruit flies.

Technology for Rapid Detection of Cyromazine Residues in Fruits and Vegetables: Molecularly Imprinted Electrochemical Sensors.

Cyromazine is an insect growth regulator insecticide with high selectivity and is widely used in the production and cultivation of fruits and vegetables. In recent years, incidents of excessive cyromazine residues in food have occurred frequently, and it is urgent to establish an accurate, fast, and convenient method for the detection of cyromazine residues to ensure the safety of edible agricultural products. To achieve rapid detection of cyromazine residues, we prepared a molecularly imprinted electrochemical sensor for the detection of cyromazine residues in agricultural products. Samples of tomato (Lycopersicon esculentum Miller), cowpea (Vigna unguiculata), and water were tested for the recovery rate of cyromazine. The results showed that the concentration of cyromazine showed a good linear relationship with the peak response current of the sensor developed in this study. The lower limit of detection for cyromazine was 0.5 µmol/L, and the sensor also had good reproducibility and interference resistance. This paper can be used as a basis for the study of methods for the detection of cyromazine residues in edible agricultural products.

Identification of male and female pupal characteristics of Zeugodacus cucurbitae (Coquillett) via machine vision.

Images of original pupae of Zeugodacus cucurbitae (Coquillett) were normalized, grayed, and segmented to identify male and female pupae of this species via machine vision. The image of each pupa was divided into 25 small areas. The differences in surface texture features in each small area within 11 days were compared. The texture characteristics of both male and female pupae were screened by combining the eclosion of both sexes of Z. cucurbitae (Coquillett). Results indicated that the pectinate setae on the abdominal backplane could be used as a basis for the identification of the male and female pupa of Z. cucurbitae (Coquillett). Moreover, machine vision correctly identified these characteristics with an accuracy of 96.0%. This study lays a foundation for the identification of male and female pupae using machine vision and also for the comprehensive control of Z. cucurbitae (Coquillett).

Dynamic expression analysis of Vitelloin-related genes in Zeugodacus cucurbitae (Coquillett) driven by short-term high-temperature stress.

Zeugodacus cucurbitae (Coquillett) is an important pest of fruit and vegetable crops in tropical and subtropical regions. Previous studies have shown that short-term high-temperature stress has a significant effect on the oviposition behavior of three successive generations (F1 -F3 ) of Z. cucurbitae (Coquillett). For the clarification of the molecular response of the oviposition behavior of Z. cucurbitae (Coquillett) to short-term high-temperature stress, three Vitellogenin (Vg) genes, namely, Vg-1, Vg-2, and Vg-3, and one Vitellogenin receptor (VgR) gene were selected; 25°C was used as the control treatment; and 33°C, 37°C, 41°C, and 45°C were set as the high-temperature treatments. Newly emerged adults of the F1 generation were treated for 1 h, and the expression dynamics of the target genes were analyzed 7 days after the emergence of three successive generations of adults. Results showed that the expression of the Vg gene in the 33°C and 37°C groups was upregulated compared with that in the control group, and the difference among the 41°C, 45°C, and control groups was small. VgR gene expression level gradually increased in each treatment group with the increase in the number of days and peaked on Days 6 and 7. Compared with the control group, the expression of VgR gene in the F1 generation was downregulated in the high-temperature treatment group over 7 days. On Day 7, the expression level of the VgR gene in the F2 and F3 generations in the 37°C and 45°C groups was significantly higher than that in the F2 and F3 generations in the control group. In conclusion, Vg and VgR are transformed and utilized differently after short-term high-temperature treatment.

The vitellogenin receptor gene is involved in lifespan regulation of Zeugodacus cucurbitae (Coquillett) after short-term high-temperature treatment.

Zeugodacus cucurbitae (Coquillett) is a highly damaging agricultural pest in many tropical and subtropical countries around the world and high temperatures usually affect its survival. To clarify the effect of short-term high temperatures on the survival and lifespan of Z. cucurbitae, newly emerged adults of three consecutive generations (F1, F2, and F3) were exposed to 25 °C, 33 °C, 37 °C, 41 °C, or 45 °C treatments for 1 h. The effect of these temperatures on survival and lifespan was evaluated using biological indicators such as lifespan and pupation rate. Then, to study the molecular regulatory mechanism of the lifespan of Z. cucurbitae after short-term high-temperature treatment, we exposed the newly emerged adults to 25 °C or 45 °C treatments for 1 h and used siRNA to interfere with the expression of the vitellogenin receptor (VgR) gene in the female to study the effect of the VgR gene on the lifespan of Z. cucurbitae. The results showed that the survival rate, lifespan, pupae weight, pupation rate, and emergence rate of Z. cucurbitae decreased with increased temperature, while the female sex ratio of offspring increased. The heat resistance of females was higher than that of males. Interference with the expression of the VgR gene resulted in shortening of the female's lifespan by approximately 60% after exposure to 25 °C or 45 °C treatments for 1 h, which indicated involvement of the VgR gene in the regulation of Z. cucurbitae lifespan. This study provides a reference to guide integrated control of Z. cucurbitae in high-temperature seasons.

Smartphone-based molecularly imprinted sensors for rapid detection of thiamethoxam residues and applications.

In order to achieve rapid detection of thiamethoxam residues in mango, cowpea and water, this study modified the screen printed carbon electrode (SPCE) to make a specific molecular imprinting sensor (Thiamethoxam-MIP/Au/rGO/SPCE) for thiamethoxam. An integrated smartphone platform was also built for thiamethoxam residue analysis. The performance of the complete system was analyzed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The system was then applied for the rapid determination of thiamethoxam residues in water, mango and cowpea samples. The results showed that the molecular sensor showed good linearity in the range 0.5-3.0 µmol/L of thiamethoxam. The detection limit of thiamethoxam was 0.5 µmol/L. Moreover, the sensor had good reproducibility and anti-interference performance. The average recovery rates of the pesticide residues in water, mango and cowpea samples were in the range of 90-110% with relative standard deviations < 5%. The rapid detection system for thiamethoxam residue constructed in this study was simple, reliable, reproducible and had strong anti-interference. It has broad application prospects in the field detection of thiamethoxam residue, and serves as a valuable reference for the further development of rapid detection technology of pesticide residues in the field of environment and food safety.

Analysis of imidacloprid residues in mango, cowpea and water samples based on portable molecular imprinting sensors.

Imidacloprid is a neonicotinoid insecticide widely used in the production and cultivation of crops. In recent years, the extensive use of imidacloprid in agricultural production has resulted in large amounts of pesticide residues in agricultural products and the environment. Therefore, it is necessary to establish a rapid, accurate, sensitive and convenient method for detecting imidacloprid pesticide residues to ensure the safety of agricultural products and the environment. To clarify how to use the molecular imprinting method for the electrochemical rapid residue detection of imidacloprid. This paper selected reduced graphene oxide and gold nanoparticles as modifiers modified on screen-printed carbon electrodes (SPCE) chitosan as a functional monomer, and imidacloprid as template molecule to prepare molecularly imprinted polymer, and applied this sensor to the residue detection of imidacloprid. The results showed that the concentration of imidacloprid showed a good linear relationship with the peak response current, and the detection limit of imidacloprid was 0.5 µM, while the sensor had good repeatability and interference resistance. The recoveries of imidacloprid spiked on three samples, mango, cowpea and water, were in the range of 90-110% (relative standard deviation, RSD<5%), which proved the practicality and feasibility of the assay established in this paper. The results of this paper can be used as a basis for the research on the detection of imidacloprid pesticide residues in food or environment.