Chikungunya fever (CHIKF), a condition caused by the Chikungunya virus (CHIKV), has triggered a pervasive pandemic in tropical and subtropical regions worldwide in recent years, affecting over 10 million individuals across 125 countries, especially in South and Southeast Asia. China has also experienced a notable increase in imported CHIKF cases, with Foshan (Guangdong Province) witnessing a large-scale CHIKF outbreak in July 2025 that had resulted in more than 9 000 confirmed cases as of August 9, posing a severe threat to public health security. CHIKV is primarily classified into the West African genotype (WA), the East/Central/South African genotype (ECSA), and the Asian genotype (Asian). These genotypes exhibit varying patterns in geographical prevalence and clinical severity. This review presents the distribution of CHIKV genotypes detected in China, and analyzes the risk of CHIKV transmission.

Objective To investigate the differences in mosquito species composition and density fluctuation between different terrains and habitats in Zhejiang Province, China from April to November 2021, so as to provide a scientific reference for mosquito control and mosquito-borne disease prevention. Methods From April to November 2021, five types of habitats were selected in counties/cities/districts of Zhejiang Province, including residential areas, parks, hospitals, rural households, and livestock sheds, and mosquitoes were monitored once at the beginning of each month using the light trap method. Excel 2021 software was used to summarize the mosquito population and density data, and SPSS 15.0 software was used for statistical analysis. A descriptive analysis was employed to investigate the difference in mosquito density fluctuation. The Chi-square test was used for the difference in mosquito species composition between different terrains and between habitats. The rank-sum test was used for the difference in mosquito density. Results In 2021, 103 669 female adult mosquitoes were captured in Zhejiang Province, and Culex tritaeniorhynchus was the dominant mosquito species, accounting for 53.40%. There was a significant difference in the species composition of mosquito between different terrains (χ²=40 563.669, P<0.001) and between habitats (χ²=60 457.931, P<0.001). Apart from Aedes albopictus, other species of mosquitoes were numerous in livestock sheds. The mosquito density was 8.48 mosquitoes/light·night in Zhejiang Province in 2021, and the mosquito density fluctuation curve showed a single-peak from April to November, reaching a peak in June, which was 25.48 mosquitoes/light·night. Conclusions There exist significant differences in mosquito species composition and density fluctuation trend between different terrains and between habitats in Zhejiang Province. Counties/cities/districts in Zhejiang Province should develop different mosquito surveillance programs and preventive and control measures based on the distribution and density fluctuation of mosquito populations in their respective region.

Objective: To investigate the prevalence of Wolbachia infection among the dengue vectors Aedes aegypti and Ae. albopictus in a dengue-endemic area, Jinghong, Yunnan Province, China, so as to provide a scientific basis for the application of Wolbachia for mosquito control. Methods: The female and male adults and larvae of Ae. aegypti and Ae. albopictus were collected in Jinghong. Genomic DNA was extracted from single mosquito samples. Based on the Wolbachia surface protein gene (wsp), universal primers were designed for polymerase chain reaction (PCR) amplification and detection to calculate the infection rate of Wolbachia; and for positive samples, wAlbA and wAlbB genotypes were identified through PCR amplification with the specific primers to analyze the status of co-infection. For all positive samples, the wsp gene was sequenced for a phylogenetic analysis. The Chi-square test or Fisher's exact test was used to compare the infection rate of Wolbachia by species, development stage, and sex of Ae. aegypti and Ae. albopictus. Results: A total of 480 Ae. aegypti samples were collected, 17 of which tested positive for Wolbachia, indicating a natural infection rate of 3.54%. Among the 96 Ae. albopictus samples, 89 were positive for Wolbachia, resulting in a natural infection rate of 92.71%. The natural Wolbachia infection rate of Ae. aegypti was significantly different from that of Ae. albopictus (χ²=423.581, P < 0.001). In Ae. aegypti, Wolbachia natural infection rates did not differ significantly between females (2.50%) and males (4.38%) (χ²=0.847, P=0.357) or between adults (3.44%) and larvae (3.75%) (χ²=0.030, P=1.000). In Ae. albopictus, no significant difference was observed in the Wolbachia natural infection rates between females (96.86%) and males (90.63%) (χ²=1.067, P=0.302) or between adults (93.75%) and larvae (90.63%) (χ²=0.308, P=0.579). Aedes aegypti had a significantly lower natural Wolbachia infection rate than Ae. albopictus in both adults (χ²=288.638, P < 0.001) and larvae (χ²=135.018, P < 0.001) as well as in both female (χ²=185.350, P < 0.001) and male adults (χ²=185.492, P < 0.001). For 17 Wolbachia-positive Ae. aegypti samples, 6 were positive for wAlbA, 3 were positive for wAlbB, and 8 were positive for wAlbA+wAlbB, with a co-infection rate of 47.06% (8/17). Among 89 positive Ae. albopictus samples, 9, 2, and 78 were positive for wAlbA, wAlbB, and wAlbA+wAlbB, respectively, with a co-infection rate of 87.64% (78/89). The co-infection rate was significantly lower in Ae. aegypti than in Ae. albopictus (χ²=15.356, P < 0.001). In the analysis of the wsp gene sequence of 106 samples, a total of 21 haplotypes were found, including 5 shared haplotypes and 16 private haplotypes (4 in Ae. aegypti and 12 in Ae. albopictus); the ratio of samples with shared haplotypes to those with private haplotypes was 13∶4 in Ae. aegypti and 74∶15 in Ae. albopictus; H2 was the major haplotype, involving 39 Wolbachia sequences (8 in Ae. aegypti and 31 in Ae. albopictus), which showed a dispersive geographical distribution and was detected in all the positive samples. Conclusion: Natural Wolbachia infection is present in both Ae. aegypti and Ae. albopictus populations in Jinghong, with a significantly lower infection rate in Ae. aegypti than in Ae. albopictus, consistently observed across both larval and adults stages, but with no significant difference in the infection rates between larvae and adults within the same species. The development stage and sex do not influence the natural infection rate of Wolbachia in the same species of Aedes mosquitoes. Aedes albopictus harbors more diverse Wolbachia haplotypes than Ae. aegypti, indicating a higher degree of gene differentiation in Ae. albopictus.

Objective To isolate and identify viruses in Aedes albopictus specimens from Shunyi District, Beijing, China in 2021. Methods The virus was isolated by parallel inoculation of Syrian hamster kidney cell line BHK-21 and Ae. albopictus C6/36 cells with mosquito grinding liquid, and molecular biological identification was carried out for the virus isolates. Results A virus isolate (AalDV-8) was isolated from Ae. albopictus specimens collected from the field in Shunyi District, Beijing in 2021, which could cause C6/36 cell lesion. The nucleotide sequence analysis of the virus genome coding region showed that AalDV-8 virus was a single-stranded DNA virus with a total length of 3 335 nt, encoding 2 non-structural proteins (NS1 and NS2) and 1 capsid protein (VP). The nucleotide (amino acid) sequence lengths of the three proteins were 2 376 nt (791 aa), 1 092 nt (363 aa), and 1 071 nt (356 aa), respectively. The phylogenetic analysis showed that AalDV-8 virus belonged to Brevihamaparvovirus group and was closely related to AalDV-7 virus isolated from Ae. albopictus in Guangzhou, China. Conclusion This is the first time to isolate Brevihamaparvovirus from the field Ae. albopictus collected from in Beijing.

As a mosquito-borne infectious disease, malaria remains a significant global public health threat. After generations of control efforts, China was certified as a malaria free country by the World Health Organization in 2021, which was a remarkable achievement for global malaria control. Recently, a special collection titled "Malaria control lessons from China" was published in the BMJ, comprising five analysis articles. The collection highlights China's strategies for malaria elimination, including innovative Anopheles larval control strategies, post-elimination preparedness, vector surveillance in high-burden areas, and cross-border collaboration in border regions.

Objective To investigate the density changes and seasonal fluctuations of Aedes albopictus in Huangpu District, Guangzhou, China, and evaluate the risk of dengue fever transmission, so as to provide a basis for the prevention and control of the dengue vector. Methods The surveillance data on the density of Ae. albopictus between 2019 and 2023 were collected from 17 subdistricts/townships in Huangpu District. The data were sorted and analyzed for changes in indices such as Breteau index (BI), standard space index (SSI), mosquito ovitrap index (MOI), and adult mosquito density index (ADI). Descriptive epidemiology was used to analyze the data and determine the risk levels of mosquito vector density based on larval mosquito indices (BI or SSI) and adult mosquito densities (MOI or ADI). Chi-square tests were used for comparing the rates. Results From 2019 to 2023, BI, SSI, MOI, and ADI in Huangpu District were 2.91-5.58, 0.64-1.41, 4.18-7.52, and 2.63-5.15 mosquito/person·h, respectively. The population density of Ae. albopictus was at a relatively low level from November of one year to March of the following year and showed a rapid upward trend starting in April; it remained at a peak plateau from May to September and gradually decreased after October. The proportion of subdistricts/townships grade 0 risk was highest in January and February, and the proportion of grades 1, 2, and 3 risks peaked from April to October. From 2019 to 2022, the proportion of subdistricts/townships grades 2 and 3 risks at the mosquito vector density surveillance sites showed a decreasing trend year by year, while it significantly increased in 2023. Conclusions The inspection and cleaning of mosquito breeding sites should begin earlier than April. The mosquito vector density peaks from May to September, posing a high risk of dengue fever transmission. It is necessary to raise public awareness of mosquito prevention, conduct timely mosquito control, and prevent the development and spread of dengue fever.

Objective To compare the effectiveness of three chemical attractants (A, B, and C) and carbon dioxide (CO₂) as well as their combinations in attracting and trapping common mosquitos by conducting experiments in large residential areas, so as to provide a scientific basis for the application of chemical attractants and CO₂ in mosquito surveillance and control. Methods Mosquito attracting and trapping experiments were conducted in the field using three attractants over 10 consecutive days. The mosquito attracting and trapping abilities were analyzed for each day. Experiments with the attractants and combination of the attractants and 150 ml/min flow CO₂ were conducted using Latin square design and cross-over method. Analysis of variance and rank sum test were performed to evaluate the effectiveness of the attractants and CO₂ in mosquito attracting and trapping, as well as the impact of CO₂ on the species and sex of mosquitos attracted and trapped. Results The average numbers of mosquitos attracted and trapped by attractants A, B, and C over 10 consecutive days were 220.00, 203.67, and 16.67, respectively, with the maximum number being 46, 49, and 5 per day, respectively. Attractant A, double attractant A, and attractant A combined with 150 ml/min flow CO₂ attracted and trapped 358, 784, and 1 268 mosquitos, respectively, with significant differences in any two of the three groups (all P<0.05). Attractants A and B combined with 150 ml/min flow CO₂ respectively enhanced the effectiveness of attracting mosquitos, with significant differences observed in Culex pipiens quinquefasciatus and Aedes albopictus (all P<0.001) and between the female and male mosquitoes ofthem(all P<0.001). Conclusions Chemical attractants have a certain lasting effect in trapping mosquitos in the field. The combination of attractants with CO₂ can enhance the trapping effect more significantly than increasing the portion of attractants, making them applicable in mosquito surveillance and control.

Objective To investigate the species composition, population density, and seasonal variation of flies in Jiangbei District of Ningbo, Zhejiang Province, China, and explore the influence of meteorological factors on fly density, so as to provide a scientific basis for fly control. Methods From April to November in 2019-2022, fly density was monitored by the cage trapping method at 12 surveillance sites in Jiangbei District. The Chi-square test and one-way analysis of variance were used to compare the data of different years and different habitats. A multiple linear regression analysis was used to analyze the correlation between fly density and meteorological factors. Results A total of 732 flies were captured, with a total fly density of 1.92 flies/cage. The dominant fly species were Musca domestica and M. sorbens, accounting for 80.74% of the total catch. In different habitats, the fly density was the highest in farmers' markets (2.48 flies/cage) and the lowest in greenbelts (1.42 flies/cage). There was no significant difference in fly density between different habitats (F=0.680, P=0.581). The fly density peaked from July to September, and the highest density was 6.67 flies/cage in August 2019. There was a significant difference in the seasonal variation of fly density between different years (F=3.471, P=0.029). Fly density was significantly associated with mean monthly temperature (β=0.357, P=0.008) and mean monthly wind speed (β=-0.844, P=0.006). Conclusions The dominant fly species in Jiangbei District are M. domestica and M. sorbens, the fly density is highest in the agricultural market, and the peak activity period is from July to September. It is recommended to carry out comprehensive prevention and control measures for dominant fly species in key areas before the peak fly activity period.

Objective: To investigate the species composition, density, habitat distribution, and seasonality of rodents in Yuxi, Yunnan Province, China, so as to provide a scientific basis for the formulation of rodent control measures. Methods: From 2018 to 2024, rodent density was monitored by night cage-trapping method at three types of habitats (urban residential areas, special industries, and rural natural villages) across eight counties (districts) in Yuxi. Statistical analyses of surveillance data were performed using Excel 2013 and SPSS 21.0 softwares. Rodent density and species composition were compared using the Chi-square test. The temporal trend in rodent density was determined using a Joinpoint log-linear regression model, with Monte Carlo permutation testing for model optimization. Results: A total of 128 311 effective cage traps were placed in Yuxi from 2018 to 2024, capturing 2 016 rodents in total. The average density of rodents was 1.57%, with the highest level (2.01%) in 2020 and the lowest level (1.12%) in 2024. Rattus norvegicus was the predominant species in Yuxi, accounting for 64.04% of the total catches. Significant differences were detected in rodent density (χ²=62.460, P < 0.001) and species composition (χ²=38.734, P < 0.001) across different years. The density of R. norvegicus exhibited a significant downward trend [annual percent change (APC)=-8.639, 95% confidence interval: -16.388-0.172, Z=-2.621, P=0.047], with no statistically significant trends in the average rodent density (Z=-1.646, P=0.161), R. tanezumi density (Z=0.999, P=0.363), and Mus musculus density (Z=-0.617, P=0.564). Among the three types of habitats, the density of rodents was highest in special industries (1.79%), followed by rural natural villages (1.57%) and urban residential areas (1.32%). The disparity in the rodent densities of the habitats was statistically significant (χ²=32.430, P < 0.001). Across the eight surveillance sites, rodent density differed significantly (χ²=508.162, P < 0.001), with the highest density in Yuanjiang Hani, Yi and Dai Autonomous County (3.42%), the second in Jiangchuan District (1.89%), and the lowest in Hongta District (0.72%). The average rodent density showed a single peak in July at 1.94%, and this seasonal pattern was observed in all the habitats. Seasonality was distinct for R. norvegicus among various rodent species, with the peak observed in July. Conclusions: From 2018 to 2024, rodent density in Yuxi increased at first and decreased afterwards; rodent density and species composition differed by year, habitat, and surveillance site; and the density of R. norvegicus exhibited a declining trend, while the average rodent density, R. tanezumi density, and M. musculus density remained stable. Comprehensive rodent control measures should be carried out according to rodent activities and fluctuations, with the focus on special industries and the peak month July. It is necessary to strengthen long-term surveillance and research on control strategies for rodents and rodent-borne diseases to lower the density of rodents and reduce rodent-borne diseases.

Objective To investigate the population composition and arbovirus infection of Aedes aegypti and Ae. albopictus in Jinghong, Xishuangbanna Dai Autonomous Prefecture (Xishuangbanna Prefecture), Yunnan Province, China during the dengue fever epidemic season in 2023, so as to provide a basis for the prevention and control of dengue fever and other arboviral diseases. Methods During the dengue fever epidemic season in 2023 (from August to October), the change of population composition of Ae. aegypti and Ae. albopictus was monitored in urban areas and Aedes mosquitoes were collected using the double mosquito net method. The infections with Dengue virus, Chikungunya virus, and Zika virus were detected using quantitative PCR (qPCR). The E gene sequences of the viruses were amplified using reverse transcription-PCR (RT-PCR), and a phylogenetic analysis was performed for homological analysis. Results A total of 730 Aedes mosquitoes were collected, of which 548 (75.07%) were Ae. aegypti and 182 (24.93%) were Ae. albopictus. All mosquitoes were divided into 76 groups (21 groups for Ae. albopictus and 55 groups for Ae. aegypti) based on species, sex, and time and location of acquisition. Out of the 76 groups, 11 (14.47%) tested positive for Dengue virus type 1 (DENV-1), yielding an infection rate of 9.52% (2/21) for Ae. albopictus and an infection rate of 16.36% (9/55) for Ae. aegypti, with no significant difference between the two species (χ2=0.574, P=0.449). Zika virus and Chikungunya virus were not detected in any of the mosquitoes. Four DENV-1 E gene sequences (1 from Ae. albopictus and 3 from Ae. aegypti) were successfully obtained from the 11 groups of DENV-1 positive specimens. The sequence similarity of the four sequences was 100%, and all sequences belonged to genotype Ⅰ. The phylogenetic analysis revealed that the strains were closely related to the 2023 Jinghong strain, 2023 Guangzhou strain, 2019 Laos strain, and 2019 Myanmar strain. Conclusions Ae. aegypti is more widely distributed than Ae. albopictus in Jinghong during the dengue fever epidemic season, and DENV-1 is detected in both species. Investigation and research should be enhanced for arboviral infection with Aedes mosquitoes.

Objective: To investigate the changes in the resistance of Blattella germanica to commonly used insecticides in Jinnan District, Tianjin, China in 2021 and 2024, so as to provide technical guidance for the use of sanitary insecticides against B. germanica in Jinnan District. Methods: B. germanica were collected from different directions in Jinnan District, and the F1 generation male adults were selected as the experimental insects. They were tested for the levels of resistance to six commonly used insecticides according to the residual film method of diagnostic dose method recommended by the Test Methods of Cockroach Resistance to Insecticides—The Bioassay Methods for B. germanica (GB/T26352-2010). The median knockdown time (KT₅₀) and 95% confidence interval were calculated using the toxicity regression line method in SPSS 19.0. The resistance ratio (RR) was calculated based on the KT₅₀ of sensitive strains in relevant literature. Results: In 2021, RR of B. germanica to six insecticides ranged from low to high: propoxur (RR=0.52, susceptible), lambda-cyhalothrin (RR=2.34, low resistance), acephate (RR=2.54, low resistance), beta-cypermethrin (RR=3.53, low resistance), permethrin (RR=4.60, low resistance), and deltamethrin (RR=5.03, low resistance). RR in 2024 ranged from low to high: acephate (RR=1.51, susceptible), propoxur (RR=2.78, low resistance), lambda-cyhalothrin (RR=7.77, low resistance), beta-cypermethrin (RR=9.03, low resistance), deltamethrin (RR=11.26, medium resistance), and permethrin (RR=32.80, high resistance). From 2021 to 2024 in Jinnan District, the resistance of B. germanica to permethrin increased from low to high levels; the resistance to deltamethrin increased from low to medium levels; the resistance to beta-cypermethrin and lambda-cyhalothrin persisted at low level, but an increasing trend in RR had been observed; and the response to propoxur changed from suscepitible status to low resistance. Conclusions: The resistance levels of B. germanica to six insecticides in Jinnan District increase in 2024 compared with 2021, with notable increases in resistance to pyrethroids. It is suggested to suspend using permethrin and deltamethrin and adopting insecticide rotation strategies or new cockroach control methods, so as to delay the progression in the resistance of B. germanica to common insecticides in Jinnan District.

Objective To investigate the resistance level of Aedes albopictus to three pyrethroid insecticides and the distribution of their knockdown resistance genotypes in Liaoning Province, China, so as to provide a scientific basis for the prevention and control of Ae. albopictus and the standardized use of insecticides in the region. Methods From July to August 2023, adult mosquitoes and larvae were collected from breeding sites of Ae. albopictus in Dalian and Yingkou in Liaoning Province. After mosquitoes were identified by morphology as Ae. albopictus, their resistance to three pyrethroid insecticides (permethrin, deltamethrin, and beta-cypermethrin) was determined by the adult mosquito WHO tube assay. The genomic DNAs of single mosquito were extracted, and the partial fragment of voltage-gated sodium channel (VGSC) gene was amplified by polymerase chain reaction. Descriptive statistical analysis method was used for the analysis of knockdown resistance genes mutations in Ae. albopictus after sequencing. Results Adult Ae. albopictus mosquitoes in Dalian had have possible resistance to permethrin, deltamethrin, and beta-cypermethrin. Adult Ae. albopictus mosquitoes in Yingkou area had developed resistance to permethrin, deltamethrin, and beta-cypermethrin. A total of 110 Ae. albopictus from two field populations were detected, and 220 gene sequences were obtained, with the length of about 400 bp. Mutations were detected at 1016, 1532, and 1534 loci of Ae. albopictus. At the 1016 locus, there were two alleles, namely wild-type GTA/V (82.73%) and mutant GGA/G (17.27%); there were three genotypes, namely wild-type homozygote V/V (68.18%), wild-type/mutant heterozygote V/G (29.09%), and mutant homozygote G/G (2.73%). At the 1532 locus, there were two alleles, namely wild-type ATC/I (86.82%) and mutant ACC/T (13.18%); there were three genotypes, namely wild-type homozygote I/I (76.36%), wild-type/mutant heterozygote I/T (20.91%), and mutant homozygote T/T (2.73%). At the 1534 locus, there were four alleles, namely wild-type TTC/F (50.46%), mutant TCC/S (23.64%), mutant TGC/C (15.45%), and mutant CTC/L (10.45%); there were eight genotypes, namely wild-type homozygote F/F (24.55%), wild-type/mutant heterozygotes F/S (24.55%), F/C (11.82%), and F/L (15.45%), mutant homozygotes S/S (9.09%) , C/C (7.27%), and L/L (2.73%), and mutant heterozygote S/C (4.54%). Conclusions Adult Ae. albopictus mosquitoes in Dalian of Liaoning Province have possible resistance to the three pyrethroid insecticides, and adult Ae. albopictus mosquitoes in Yingkou are resistant to the three pyrethroid insecticides. The knockdown resistance gene of Ae. albopictus is mutated in Dalian and Yingkou areas, with a high mutation rate and complex and diverse mutations at the 1534 locus. Sustained attention should be paid to the resistance level of Ae. albopictus and reduce the use of pyrethroid insecticides, so as to delay the emergence and development of insecticide resistance.

Objective To analyze the effect of integrated cockroach control and the cost of each component in a catering service environment, so as to provide a reference for cockroach control strategy and cost control. Methods In a catering service environment (86.5 m², including kitchen and dining room), integrated pest management (IPM) in combination with insecticide resistance assessment (glass bottle method), density surveillance (sticky trapping method), environmental management, physical control, chemical control, and health education were used. Then the cockroach density changes were continuously monitored and the cost of each component (labor, insecticides, consumables, equipment, etc.) was recorded. Excel 2021 software was used for data analysis and description. Results Under four spray-type insecticides treatments, all the mortality rates of Blattella germanica exceeded 90.00%. This control process lasted 4 weeks, including 6 times of density surveillance and 4 times of integrated control. The density was 43.50 cockroaches/night·trap before control. The control was conducted once a week. The density declined to 6.50, 3.50, and 0.50 cockroaches/night·trap at weeks 1-3, respectively. Then the density declined to zero at week 4 and remained at zero in the following five months. The costs of this control totaled 1 723.22 yuan (equivalent to 19.92 yuan/m²). The labor cost was the highest, amounting to 1 470.00 yuan and accounting for 85.31% of the total cost. The labor cost during the first integrated control, which included comprehensive environmental management, accounted for 64.29% of the total labor cost. Chemical control insecticides cost ranked second, which accounted for 6.59% of the total cost. Conclusions For cockroach control in the catering service environment, especially with a high cockroach density, IPM strategy based on environmental management can achieve rapid and long-lasting cockroach control. Despite the high labor cost in the early stage, the cost in the later stage will decrease to a level similar to that of chemical control alone. This is an environmentally friendly and sustainable control strategy.

Objective To investigate the density, infestation status, distribution characteristics, and seasonal fluctuations of cockroaches in the urban area of Rizhao, Shandong Province, China, so as to provide a basis for the Patriotic Health Campaign and scientific control of cockroaches. Methods Cockroach surveillance data by the sticky trap method were collected at farmers' markets, supermarkets, catering industry areas, hotels, hospitals, and residential areas in the main urban area of Rizhao from 2018 to 2023. Excel 2010 was used to calculate cockroach density and infestation rate. With the use of SPSS 22.0, the relationship between cockroach density and meteorological factors was analyzed through Spearman rank correlation analysis, and the infestation rates of cockroaches in different habitats were compared using the Chi-square test. Results From 2018 to 2023, the captured cockroaches in the urban area of Rizhao City were all Blattella germanica, with an annual average density of 0.016 cockroaches/trapping paper and the average infestation rate was 1.34%, and there was a statistically significant difference in the infestation rate of cockroaches in different habitats (χ²=15.274, P<0.001). The average density and infestation rate of cockroaches in farmer's markets were the highest, at 0.045 cockroaches/paper and 4.38%, respectively; followed by residential areas (0.021 cockroaches/trapping paper and 1.55%, respectively). The seasonal fluctuation in the monthly average density of cockroaches shows a unimodal distribution, reaching its peak activity in July. The monthly average temperature (r_s=0.540, P=0.001), the monthly average maximum temperature (r_s=0.532, P=0.002), the monthly average minimum temperature (r_s=0.552, P=0.001), and the monthly average relative humidity (r_s=0.497, P=0.004) were all positively correlated with the monthly density of cockroaches (all P<0.05). Conclusions The density of cockroaches in Rizhao is at a low level. The focus of cockroach control should be placed on B. germanica and in farmers' markets and residential areas, and the strategies should adopt environmental management combined with the use of insecticides.