Mosquito-borne diseases, such as dengue fever, malaria, and Japanese encephalitis, have imposed a significant disease burden in Zhejiang Province, located on the south-eastern coast of China. Due to its suitable climate, robust tourism, and active commercial exchanges, Zhejiang has emerged as one of the provinces with the highest incidence of dengue fever. In the last century, dengue fever outbreaks occurred continuously in Hangzhou City (1928–1929, 2017), Ningbo City (1928, 2004, 2018), Yiwu City (2009), Shaoxing City (2015), and Wenzhou City (2019). According to a study, dengue fever cases were reported in 95.55% (86/90) of towns in Zhejiang province between 2015 and 2019 (1). In 2018, dengue virus genotype I was identified from Aedes albopictus sampled in Wenzhou City (2, 3). The Japanese encephalitis virus was detected in Zhejiang Province in 2023 via integrated vector surveillance of arthropod vectors, with a positive rate of 0.491‰ (unpublished data). Arboviral illnesses have become a public health threat in Zhejiang Province.

Mosquito control is believed to be a more feasible method for preventing mosquito-borne diseases than commercial vaccines and drugs (4, 5). However, traditional control measures rely heavily on chemical insecticides such as pyrethroids, organophosphates, and carbamates. Excessive and repeated use of chemical insecticides has caused serious drug resistance in field populations of mosquitoes in Zhejiang. According to the results of insecticide susceptibility tests conducted in 2020 via the Zhejiang integrated vector surveillance, almost all Ae. albopictus field populations exhibit resistance to pyrethroids (3). Knockdown resistance (kdr) mutations F1534S were detected in all Ae. albopictus field populations sampled from northern, southern, western, and central Zhejiang, with the highest mutation frequency at 88.37% (Yiwu city) (6). Resistance has become a major challenge for current mosquito control strategies in Zhejiang. Additionally, using large amounts of chemicals in residential environments may pollute the environment and harm human health. Thus, there is an urgent need to devise effective and environmentally friendly methods for controlling vector mosquitoes.

In contrast to traditional chemical control methods, attractive toxic sugar baits (ATSB) have been developed as a new mosquito control method. ATSB is based on the feeding behavior of mosquitoes. Adult mosquitoes feed on sugars such as nectar and honeydew as energy sources (7). Sugars and insecticides have been developed to attract and kill mosquitoes (8, 9). In 1965, Lea prepared a solution by mixing sugar bait with malathion in a laboratory and tested its effect on killing Aedes aegypti. An 85.2% mortality rate of the Ae. aegypti has been observed in the laboratory tests (7). ATSB has been proven effective in controlling adult mosquitoes (8). However, ATSB also uses chemical insecticides to kill mosquitoes, and insecticidal resistance cannot be avoided. Based on this consideration, we combined sugar baits and physical adhesive capture technology to develop a novel sugar bait device (NSBD) trap. The sugar bait used in the NSBD was identified via laboratory tests. Semi-field trials on NSBD have been conducted previously, showing that NSBD effectively killed Ae. albopictus and Culex quinquefasciatus (unpublished data). In this study, we selected four residential villages to test the effect of NSBD on controlling mosquitoes in a real environment, aiming to identify the effect of NSBD and clarify the most suitable sugar bait components for use in real residential environments. Finally, we evaluated the potential of NSBD for actual applications in controlling mosquitoes in residential environments.

Sugar bait has a mosquito-control history of over 60 years (8). Based on the results of previous studies, we developed a novel sugar bait device (NSBD) trap by combining sugar bait and physical adhesive capture technology to develop an effective and environmentally friendly method to control mosquitoes around human residents and prevent mosquito-borne diseases. This study evaluated the effects of NSBD traps with different sugar baits by controlling larval and adult mosquitoes in residential environments through field trials. The results showed that the NSBD traps could effectively reduce larval and adult mosquito densities, and the most suitable sugar solution concentration in the sugar bait was 10%.

In this study, four residential villages with similar geographical environments were selected. To better demonstrate the effectiveness of the NSBD, the basic mosquito densities in the four villages were assumed to be the same. Thus, 3 months of mosquito monitoring was conducted before the field trials, and no statistical differences were found in the densities of larval and adult mosquitoes among the four villages. NSBD traps were proven effective in controlling mosquitoes in residential environments, with the highest standard decrease rates of larval and adult mosquito densities of 57.80 and 86.31%, respectively. The mosquito densities at sites 3 (8% sugar solution concentration in sugar bait) and 4 (10% sugar solution concentration in sugar bait) were significantly lower than those at site 1 (control group). Similar effect had been found in some ATSBs with sugar concentrations ranging from 5 to 20% and insecticides on killing different species of mosquitoes in laboratory and field studies, which had reduced the density of mosquitoes by 52 to 96% after exposure to ATSBs (8, 12, 13).

The concept of insect baiting is not novel, it was first described in 77 AD in Historia Naturalis (14). Subsequently, an increasing number of insect-baiting attempts have been made to dissuade behavior and induce mortality (8). Sugar feeding is a basic biological habit of mosquitoes. Almost all adult mosquitoes feed on sugary meals to supplement their energy throughout their lives (12, 15–17). This behavior has always been used to control mosquitoes. In this research, sugar bait was combined with sticky black insect paper in a black bucket to lure and stick the mosquitoes, and it proved to be effective on controlling mosquitoes. Similar results had been found in MosHouse traps by Pattamaporn Kittayapong et al. After adding a sugar stick and sticky flags, its effect on capturing mosquitoes significantly increased (18). However, while NSBD traps attract and kill mosquitoes, ensuring that the provided sugar bait solution does not become a new breeding place for mosquito larvae is crucial, especially when we should use methods without chemical insecticides. Thus, many preliminary experiments have been conducted in the laboratory, and it has been shown that sugar solution concentrations above 5% could effectively prevent larval survival (unpublished data). After considering the luring effect and unsuitability for larval survival, a sugar bait with a sugar solution concentration of 8% was chosen as the baseline to explore the effect of controlling mosquitoes in real residential environments. Throughout the field trials, we found no live mosquito larvae in the NSBD traps. Black was chosen as the color of sticky insect papers and buckets because of the black preference characteristics of Ae. albopictus, which is one of the most advantageous mosquito populations in Zhejiang Province (19).

To control vector mosquitoes, several traps had been developed such as BG- Sentinel traps and backpack aspirators, which are chemically independent and effectively on collecting mosquitoes especially Aedes mosquitoes (20–22). However, they both require power source and are not cost-effective in mosquito collection (23, 24). So more economical traps had been developed to captured gravid mosquitoes such as Stick ovitraps, AedesTrap, both of which attract and capture gravid mosquitoes by creating suitable oviposition environments (23, 25). MosHouse trap was developed using odor created by hay infusion and oviposition environment to attract gravid and non-gravid mosquitoes (18). However, all of them use Bacillus thuringiensis israelensis (Bti) as substances to killing mosquito larvae, which is also one of insecticides and might induce drug resistance. The advantage of NSBD traps is low-cost, easy to use, without use of chemical insecticides and requires no power sources for its usage, it could be considered as an appropriate alternative trapping method to control mosquitoes around residential areas, then to reduce mosquito infestation and to prevent mosquito-borne diseases.

The limitation of this research is that within this investigation, only three concentration gradients of sugar solutions in the sugar bait were tested in the field trials; thus, caution should be exercised when extrapolating the results. However, according to the results of the laboratory experiments, the luring effect of sugar bait with a sugar solution concentration of 15% on Ae. albopictus and C. quinquefasciatus was much lower than that of 8%. Therefore, it can be inferred that the effect of sugar solution concentrations above 10% on mosquito control might not be better than that of concentrations below 10%. On the other hand, in the present study we focus more on the overall decrease in adult and larval mosquito density than on some specific mosquito species by considering that sugar bait could attract many mosquito species (8). And no comparison had been made on the control effect of NSBD traps on different mosquito species. In the future, more researches like the long-term efficacy of NSBD traps and mosquito species that are more likely to be controlled by NSBD traps, the variability in different environmental conditions and geographical locations would be conducted to clarify the application potential of NSBD.

In conclusion, a novel sugar bait device (NSBD) trap, developed by combining sugar bait and physical adhesive capture technology, can effectively control larval and adult mosquitoes in residential environments. Without the use of chemical insecticides, this could be an effective and environmentally friendly method for controlling mosquitoes. The most suitable sugar concentration for the sugar bait of the NCBD traps was 10%.

The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.

YW: Investigation, Methodology, Writing – original draft, Writing – review & editing. CZ: Investigation, Writing – original draft. WF: Investigation, Resources, Writing – original draft. SF: Project administration, Resources, Writing – original draft. WD: Methodology, Resources, Writing – original draft. JW: Investigation, Writing – original draft. QL: Investigation, Methodology, Writing – original draft. TL: Investigation, Writing – original draft. ML: Investigation, Writing – original draft. ZG: Writing – original draft, Writing – review & editing.