Dusky Cotton Bug Research Articles

Efficacy of Alternative Insecticides against Dusky Cotton Bug (Oxycarenus laetus) to Improve Yield Losses in Cotton Crops through Residue-based Bioassay

The study evaluates the efficacy of leufenuron, emamectin benzoate, and thiamethoxam against the Dusky Cotton Bug (Oxycarenus laetus Kirby) using residue-based bioassay methods. Key findings indicate that emamectin benzoate showed the highest efficacy with the lowest LC50 value, making it the most potent insecticide among those tested. Leufenuron and thiamethoxam followed, displaying moderate effectiveness. The results highlight the comparative advantages of emamectin benzoate in controlling Dusky Cotton Bug populations, suggesting its potential role in integrated pest management strategies. This study underscores the need for environmentally friendly alternatives to traditional insecticides in mitigating yield losses in cotton production.

Toxicity Assessment of Various Insecticides on Oxycarenus Hyalinipennis Costa (Lygaeidae: Hemiptera) in Laboratory Settings across Various Districts of Punjab, Pakistan

Cotton contributes 0.6% to the value added in GDP and 3.1% to the value added in the agriculture sector of Pakistan. The dusky cotton bug (DCB), Oxycarenus hyalinipennis (Hemiptera: Lygaeidae), is among the insect pest species of highest economic significance in cotton production in the country. Adults and nymphs feed on seeds and cotton bolls, affecting seed germination. The dusky cotton bug is a polyphagous insect that feeds on a variety of host plants. Its adults and nymphs typically feed on squares of the cotton plant, resulting in a pale yellow color of squares and subsequent shedding of infested squares. Insecticide resistance in cotton insect pests is an emerging threat to sustainable cotton production in Pakistan. A thorough understanding of resistance might be a valuable tool for implementing pest control approaches. In the present study, Clothianidin, Fipronil, Bifenthrin, Triazhophos, Deltamethrin, and Clothianidin + Imidacloprid insecticides were used in different cotton-growing districts of Punjab. Among all the insecticides used for controlling the DCB population, Clothianidin + Imidacloprid was found to be the most effective in all districts, while Deltamethrin was the least effective in District Khanewal, Bifenthrin in Dera Ghazi Khan, Rahim Yar Khan, and Vehari, and Clothainidin in Multan. Therefore, we recommend the use of a pesticide mixture (Clothianidin + Imidacloprid) as a beneficial strategy against the dusky cotton bug in various cotton-growing districts of Punjab.

English

Dusky cotton bug (DCB), Oxycarenus hyalinipennis, a serious economic sucking insect pest of cotton, is a cosmopolitan polyphagous pest with the potency to develop resistance against insecticides. The resistance was evaluated against insecticides of different chemical nature against DCB population from three cotton fields i.e., unsprayed population (Un-sp), field exposed to sucking sprays (SSp) and field exposed to bollworms sprays (BSp) using semi-opened bolls dip method.The DCB population showed differential range of resistance level against tested insecticides. These RR ratios were among susceptibility (1 fold) and tolerance to low resistance (2–10 fold) for all tested insecticides except for deltamethrin with moderate resistance (11–30 fold) for the populations of both sprayed fields. In the order of resistance for the SSp population, deltamethrin (24.4 fold) was followed by imidacloprid (6.4 fold), profenofos (4.0 fold), cypermethrin (3.2), endosulfan (2.8 fold), chlorfenapyr (2.7 fold) and chlothianidin (2.5 fold). For BSp population, RR ratios from high to low were: deltamethrin (21.2 fold) followed by imidacloprid (4.9 fold), chlothianidin (3.7 fold), cypermethrin (2.8 fold), endosulfan (2.7 fold), triazophos (2.4 fold) and profenofos (2.2 fold). Acephate was highly effective with least LC50 followed by spinosad and dimethoate, whereas, lambdacyhalothrin was least effective. Relative toxicity (RT) order from high to low for SSp population was acephate (1.00) followed by spinosad (1.33), chlorfenapyr (2.69), acetamiprid (2.77) and dimethoate (2.85). For BSp population, RT were sequenced as acephate (1.00) followed by spinosad (1.46), chlorfenapyr (1.67) and dimethoate (3.32). In control unsprayed population, RT were in order as acephate < deltamethrin < spinosad < chlorfenapyr (1.0, 1.20, 1.28 and 1.58, respectively). Lambdacyhalothrin was the least toxic against DCB population of all tested fields. From results, it can be suggested that regular insecticide resistance monitoring is crucial to avoid incidence(s) in O. hyalinipennis, and to adopt the rotational application of appropriate insecticides.

Seasonal dynamics of resistance to new chemistry and conventional insecticides in dusky cotton bug, Oxycarenus Hyalinipennis Costa (Hemiptera: Lygaeidae)

Seasonal dynamics of resistance to new chemistry and conventional insecticides in dusky cotton bug, Oxycarenus Hyalinipennis Costa (Hemiptera: Lygaeidae)

Exploring The Impact of Weather Factors on the Population Trend of Oxycarenus Laetus Kirby (Dusky Cotton Bug) and Natural Enemies in Different Agro-Ecological Zones of Sindh, Pakistan

The research work was carried out in different agro-eco-zones of Sindh, Pakistan at the experimental field area of Cotton Agriculture Research Station at Tandojam, Sakrand, Kotdiji and Sarhad, 2019. The peak population of the Dusky cotton bug (DCB) was recorded at Tandojam. The high population of natural enemies like Chrysoperla, Orius, and Mirid bug was observed from July to September. The peak pest of pest observed averagely at Tandojam and Sakrand (49 to 23%). The abiotic factors like temperature and humidity averagely at Tandojam and Sakrand (32 to 50%) followed by Kotdiji and Sarhad (41 to 18%) recorded ideal for Chrysoperla, Orius, and Mirid bug. The abiotic factors were recorded as favorable for natural population multiplication like temperature and respectively. The weather factors noted optimum for spider population at Tandojam. It was concluded that the peak population of the pest was observed in different agro-eco-zones from September and October.

Characterization of Azadirachta indica synthesized silver nanoparticles and its toxicity against Dusky cotton bug, Oxycarenus hyalinipennis Costa (Hemiptera:Lygaeidae)

Characterization of Azadirachta indica synthesized silver nanoparticles and its toxicity against Dusky cotton bug, Oxycarenus hyalinipennis Costa (Hemiptera:Lygaeidae)

Differential expression profiling of Oxycarenus laetus Kirby (Hemiptera: Lygaeidae) upon exposure to gossypol.

Gossypium hirsutum seeds are rich in gossypol. In addition to its diverse beneficial properties, it is a known anti-fertility inducing agent in humans. Oxycarenus laetus feeds on the cottonseeds and yet its courtship, mating and reproduction is unaffected. In this study, we performed a transcriptome profiling of O. laetus fed on Abutilon indicum (AB-no gossypol), G. hirsutum (GH-natural gossypol) and 1400ppm commercial gossypol-soaked GH seeds (GHGO). Illumina NextSeq-500 paired-end 75bp reads were generated and de novo assembled (48,214 genes) to identify the differentially expressed transcripts (DET) between the samples. Gene enrichment, KEGG pathway and cluster profiling of the DETs resulted in the identification of vital genes involved in the detoxification, pheromone biosynthesis, cuticle protein in the GHGO sample. Cyp4C1, Cyp6a13, Cyp6a14, Cyp4g15, Cyp4em8, Cyp303a1 were the detoxification related genes identified. Similarly, SDR dehydrogenase family 11 and fatty acid synthase in pheromone biosynthesis and cuticle proteins (RR1 and RR2) coding transcripts were found to be differentially expressed. This is the first study to report the expression of genes induced by gossypol in O. laetus. Based on the findings from the DET analysis, we conclude that the detoxification related genes of gossypol treated samples were affected.

Complete mitochondrial genome sequencing of Oxycarenus laetus (Hemiptera: Lygaeidae) from two geographically distinct regions of India

Oxycarenus laetus is a seed-sap sucking pest affecting a variety of crops, including cotton plants. Rising incidence and pesticide resistance by O. laetus have been reported from India and neighbouring countries. In this study, O. laetus samples were collected from Bhatinda and Coimbatore (India). Pure mtDNA was isolated and sequenced using Illumina MiSeq. Both the samples were found to be identical species (99.9%), and the complete genome was circular (15,672 bp), consisting of 13 PCGs, 2 rRNA, 23 tRNA genes, and a 962 bp control region. The mitogenome is 74.1% AT-rich, 0.11 AT, and − 0.19 GC skewed. All the genes had ATN as the start codon except cox1 (TTG), and an additional trnT was predicted. Nearly all tRNAs folded into the clover-leaf structure, except trnS1 and trnV. The intergenic space between trnH and nad4, considered as a synapomorphy of Lygaeoidea, was displaced. Two 5 bp motifs AATGA and ACCTA, two tandem repeats, and a few microsatellite sequences, were also found. The phylogenetic tree was constructed using 36 mitogenomes from 7 super-families of Hemiptera by employing rigorous bootstrapping and ML. Ours is the first study to sequence the complete mitogenome of O. laetus or any Oxycarenus species. The findings from this study would further help in the evolutionary studies of Lygaeidae.

Realized heritability, cross-resistance and high risk of resistance development to spirotetramat in dusky cotton bug, Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae), an emerging threat to BT cotton in Pakistan

Realized heritability, cross-resistance and high risk of resistance development to spirotetramat in dusky cotton bug, Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae), an emerging threat to BT cotton in Pakistan

Stability and fitness cost associated with spirotetramat resistance in Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae)

Dusky cotton bug, Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae) is an important pest of cotton and causing economic losses to this crop. It also remains active round the year, infesting a number of host plants. Spirotetramat is a systemic insecticide and is effective against many sucking insect pests. A field collected population of O. hyalinipennis was reared in the laboratory under continuous spirotetramat selection pressure for 21 generations for the development of resistance to spirotetramat. The Spiro-Sel population was further reared for seven generations without insecticide exposure to assess the stability of spirotetramat resistance. Leaf dip method was used for the bioassays and selection. In this study, the impact of spirotetramat resistance on its stability and life history traits of Spiro-Sel, C1 (15 Spiro-Sel♀ × 15 UNSEL ♂) and C2 (15 Spiro-Sel♂ × 15 UNSEL ♀) O. hyalinipennis was assessed. Spiro-Sel (G21 ) population developed 2333-fold and 20.83-fold resistance compared with the susceptible and unselected (UNSEL) populations, respectively. Resistance to spirotetramat was unstable after seven generations (G28 ) when reared without exposure to any insecticide. A significant reduction in overall nymphal survival, fecundity, egg hatching and net reproductive rate of Spiro-Sel population was observed when compared with UNSEL population. Intrinsic rate of natural increase, biotic potential and mean relative growth rate were also lower in Spiro-Sel population compared to UNSEL population. The Spiro-Sel, C1 and C2 population had a relative fitness of 0.44, 0.51 and 0.44, respectively. Results of our study suggested that fitness cost is involved in the development of spirotetramat resistance. Unstable resistance and high fitness cost may provide great benefits to limit the evolution of resistance to spirotetramat in O. hyalinipennis. © 2021 Society of Chemical Industry.

Gut Metagenomic Profiling of Gossypol Induced Oxycarenus laetus (Hemiptera: Lygaeidae) Reveals Gossypol Tolerating Bacterial Species.

The online version contains supplementary material available at 10.1007/s12088-021-00964-0.

Evaluation of resistance stability and fitness costs in dimethoate-selected strain of Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae)

• A 157.76-fold resistant strain to dimethoate was evaluated for its fitness attributes and resistance stability. • Dimethoate resistance was unstable upon rearing the selected strain for five generations without dimethoate exposure. • The relative fitness (Rf) of dimethoate selected strain was 0.77. • Net reproductive rate, intrinsic rate of natural increase, and biotic potential were lowered in selected strain. • The Rf evaluated for Cross 1 and Cross 2 was 1.02 and 0.91, respectively. Dimethoate belongs to organophosphate (OP) group of insecticides, used worldwide against several economic insect pests. This study was done to evaluate the fitness costs and stability of dimethoate resistance in a previously selected strain of dusky cotton bug, Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae), a serious sucking pest of cotton. Previously, dimethoate selected (Dimeth-SEL) strain was developed after selecting O. hyalinipennis for six generations in the laboratory. The selected strain expressed resistance ratios (RRs) of 157.76-, and 14.13-fold to dimethoate when compared with Lab Pop, and Unsel Pop, respectively. Data on fitness traits of selected strain reveal that the relative fitness ( Rf ) of Dimeth-SEL was 0.77 along with significant decrease in nymphal survival, hatchability, net reproductive rate ( R0 ), intrinsic rate of natural increase ( r m ), and biotic potential ( Bp ). The Rf evaluated for Cross 1 and Cross 2 was 1.02 and 0.91, respectively. For resistance stability, Dimeth-SEL (G 6 ) was left unexposed to dimethoate for five generations (G 7 -G 11 ) and the bioassay results at G 11 showed that removal of selected strain from selection pressure resulted in a significant decline in dimethoate resistance. It can be inferred from these results that resistance to dimethoate was developed in O. hyallinipennis at the expense of very high energetic costs and that these costs might also contributed in lowering the resistance levels towards susceptibility after stopping the selection for several generations. These results have practical implications in managing the dimethoate resistance against O. hyallinipennis by implementing the insecticide rotation strategy and also by delaying the dimethoate spray in the field for some generations.

Extracts of Euphorbia nivulia Buch.-Ham. showed both phytotoxic and insecticidal capacities against Lemna minor L. and Oxycarenus hyalinipennis Costa.

Many phytochemicals can affect the growth and development of plants and insects which can be used as biological control agents. In this study, different concentrations of crude, hexane, chloroform, butanol, and aqueous extracts of Euphorbia nivulia Buch.-Ham., an endemic plant of the Cholistan desert in South Punjab of Pakistan, were analysed for their chemical constituents. Their various concentrations were also tested for their phytotoxic and insecticidal potential against duckweed, Lemna minor L., and the dusky cotton bug, Oxycarenus hyalinipennis Costa. various polyphenols, i.e., quercetin, gallic acid, caffeic acid, syringic acid, coumaric acid, ferulic acid, and cinnamic acid were detected in different concentrations with different solvents during the phytochemical screening of E. nivulia. In the phytotoxicity test, except for 100 μg/mL of the butanol extract gave 4.5% growth regulation, no phytotoxic lethality could be found at 10 and 100 μg/mL of all the extracts. The highest concentration, 1000 μg/mL, of the chloroform, crude, and butanol extracts showed 100, 63.1, and 27.1% of growth inhibition in duckweed, respectively. In the insecticidal bioassay, the highest O. hyalinipennis mortalities (87 and 75%) were recorded at 15% concentration of the chloroform and butanol extracts of E. nivulia. In contrast, the lower concentrations of the E. nivulia extracts caused the lower mortalities. Altogether, these findings revealed that E. nivulia chloroform extracts showed significant phytotoxicity while all the extracts showed insecticidal potential. This potential can be, further, refined to be developed for bio-control agents.

Population dynamics and damage status of the dusky cotton bug, Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae) in cotton in Çukurova region of Turkey

The dusky cotton bug, Oxycarenus hyalinipennis (Costa) (Hemiptera: Lygaeidae) is a common insect species in cotton fields of the Eastern Mediterranean region of Turkey during the critical developmental period of the plants (i.e. squaring-boll formation period). Although the adults of the pest are mostly detected in young squares and bolls of cotton plants, its damage status on them is not yet known. With this study, the population dynamics and damage status of the O. hyalinipennis were investigated in a cotton field in Adana Province, Turkey in 2017 and 2018. Oxycarenus hyalinipennis adult population density increased after mid-July on the square, flower, and green bolls, and then it decreased after the first week of August. The females started to lay eggs in a period close to the opening of the mature green bolls. The population density of nymphs was higher when the mature green bolls were opened (in September). Adults were mostly found in squares (30.37% and 34.44% in 2017 and 2018, respectively) or green bolls (35.19% and 27.16% in 2017 and 2018, respectively), while nymphs were mostly found in opened bolls (65.03% and 57.45% in 2017 and 2018, respectively). With the cage trials, it has been found that adult females did not cause any damage to squares and green bolls. It has been commented that the presence of adults in these generative organs may be its behavioral characteristic rather than its feeding on these plant parts.

Effects of seasonal variation on the biology and morphology of the dusky cotton bug, Oxcarenus laetus (Kirby).

The dusky cotton bug (Oxycarenus laetus, KIRBY) a pest of several crops. The effects of winter and summer on the biology and morphology was investigated. The sampled eggs of dusky cotton bug (DCB) were kept under controlled environment for biological and morphological investigations. In winter, the mating duration of DCB was observed longer significantly (74.2 days), egg development period (3.93 days), an egg laying period (3.6 days) and hatching period (6.66 days) noted longer in winter season. Interestingly, average number of hatched egg (16.8 days) observed significantly higher in summer and the percentage of the hatching of eggs (81.95%) were also observed higher in summer as compare to winter. Whereas, the longevity of all nymph stages in winter longer days as compare to summer nymph stages. Moreover, differences were also observed between male and female development days between winter and summer. In the winter, female DCB development was suggestively higher as compare to summer (24 days). Whereas, the developmental days were noted considerably more in winter for males as compare to summer (14.93 days). On other hand, for morphological parameters, no differences were observed between winter and summer population of DCB.

Inheritance mode and metabolic mechanism of the sulfoximine insecticide sulfoxaflor resistance in Oxycarenus hyalinipennis (Costa).

Dusky cotton bug (DCB), Oxycarenus hyalinipennis (Costa) (Hemiptera: Lygaeidae), is a key insect pest of cotton. It causes huge losses to cotton and many other economically important crops. Sulfoxaflor is a newly introduced systemic insecticide that is effective against many sap-feeding insect pests such as aphids, whiteflies and true bugs. The present study was designed to characterize the inheritance of sulfoxaflor resistance in DCB. Moreover, the role of synergists in reducing sulfoxaflor resistance in DCB was also assessed. A field population of DCB has developed 1132.0-fold resistance to sulfoxaflor after 11 selected generations in the laboratory. Nonsignificant difference of reciprocal crosses was observed depending on the LC50 (median lethal concentration) values (95% confidence intervals overlapped), suggesting an autosomal mode of sulfoxaflor resistance inheritance. The degree of dominance of 0.7 for F1 (Sulfo-Sel Pop ♀ × Lab-Pop♂) and 0.6 for F1 '(Sulfo-Sel Pop ♂ × Lab-Pop♀), respectively, suggested that sulfoxaflor resistance was incompletely dominant. According to the monogenic model, the number of genes involved to induce sulfoxaflor resistance revealed that sulfoxaflor resistance was polygenic in nature. The realized heritability (h2 ) value for sulfoxaflor resistance was 0.2. The synergists experiment indicated that esterases were involved in the sulfoxaflor resistance mechanism in DCB. The current results indicate that there is autosomal, incompletely dominant and polygenic inheritance of sulfoxaflor resistance in DCB. Our results would be helpful in delaying sulfoxaflor resistance against DCB in the field. © 2021 Society of Chemical Industry.

Laboratory induced selection of pyriproxyfen resistance in Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae): Cross-resistance potential, realized heritability, and fitness costs determination using age-stage, two-sex life table

Pyriproxyfen is a biorational insecticide from IGR family, used worldwide against several economic pests. To evaluate the risk of pyriproxyfen resistance in dusky cotton bug, Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae), a major concern for cotton producers, and to formulate strategies effective to tackle resistance, a field collected population was selected with pyriproxyfen under laboratory conditions using seed-dip method. A resistant strain designated as Pyr-SEL (G18) was developed after repeatedly selecting O. hyalinipennis with pyriproxyfen over eighteen generations. Thereafter, fitness costs, realized heritability (h2) and cross-resistance were investigated. As a result of selection, Pyr-SEL (G18) developed a very high level of resistance (resistance ratio = 464.23-fold) compared with the susceptible strain unselected over twenty generations Un-SEL (G20). The Pyr-SEL (G18) conferred strong cross-resistance to bifenthrin (146.59-fold), lambda-cyhalothrin (132.96-fold) and fenoxycarb (91.06-fold), whereas showed moderate cross-resistance to diafenthiuron (28.86-fold) and fipronil (22.73-fold). The h2 estimate was 0.16 in Pyr-SEL (G18). The developmental duration of O. hyalinipennis pre-adult prolonged, but traits of λ, r and R0 reduced in Pyr-SEL (G18) compared with the Un-SEL (G20). Also, the population projection obtained lower population size for Pyr-SEL (G18) than Un-SEL (G20). Fitness studies revealed that high resistance development to pyriproxyfen lowered the relative fitness of Pyr-SEL (G18) (Rf = 0.38) compared with the Un-SEL (G20). These findings may be practically valuable in tackling O. hyalinipennis resistance for better pest management.

Characterization of genetic basis and realized heritability of bifenthrin-resistance selected in dusky cotton bug, Oxycarenus hyalinipennis (Costa) (Hemiptera: Lygaeidae) in Pakistan

Dusky cotton bug, Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae) is a major pest of cotton crop across various regions in the world, and has developed resistance to a number of insecticides including bifenthrin. In the current study, we evaluated the genetics and realized heritability (h2) of bifenthrin resistance following selection of O. hyalinipennis in the laboratory for 15 generations. The selected population of O. hyalinipennis had a resistance ratio of 554.21-fold as compared to a laboratory susceptible population. Toxicity data of reciprocal crosses F1 and F1’ revealed that bifenthrin resistance was inherited as an autosomal trait and no maternal influence was involved. The degree of dominance (DLC) values, 0.68 and 0.81 for F1 and F1’, respectively, revealed that incompletely dominant genes were governing the bifenthrin resistance in O. hyalinipennis. Resistance to bifenthrin also shifted from completely dominant (DML = 0.95) to fully recessive (DML = 0.08) trait upon changing the concentrations of bifenthrin from 165.25 ppm to 2500 ppm, respectively. The chi-square analysis of monogenic model in both back-crosses, BC1 (F1♀ × S♂) and BC2 (F1♀ × R♂) resulted in rejection of the hypothesis of monogenic resistance, which indicated that multiple factors were involved in controlling bifenthrin resistance. The estimated value of realized heritability (h2) for bifenthrin resistance was 0.09. Selection of O. hyalinipennis with bifenthrin for 15 generations induced a high resistance to bifenthrin that was autosomal, incompletely dominant and polygenic in nature. A low heritability value revealed that bifenthrin resistance could likely develop in the field but at much slower pace. These results have important implications for bifenthrin resistance management in O. hyalinipennis.

Genetic basis and realized heritability of laboratory selected spirotetramat resistance for insecticide resistance management in Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae)

Dusky cotton bug, Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae) is become a major pest of cotton. It causes damage to cotton by sucking the cell sap or by staining the cotton seed. Insect pests in Pakistan are mainly managed by use of insecticides, applying this practice leads to resistance development. In this study, O. hyalinipennis was selected with spirotetramat under laboratory conditions to investigate genetic mode of resistance to spirotetramat. Selection with spirotetramat for eleven generations resulted in a 727-fold resistance compared to the susceptible strain. The LC50 values of spirotetramat in both reciprocal crosses were significantly different from each other and degree of dominanace values were 0.25 for cross-1 and 0.01 for cross-2. Monogenic model proved the contribution of more than one gene in controlling the spirotetramat resistance. Moreover, the value for realized heritability of spirotetramat resistance was 0.13. It can be concluded that spirotetramat resistance was sex linked, polygenic and incompletely dominant. These findings could be helpful in management of spirotetramat resistance in O. hyalinipennis as incompletely dominant and polygenic resistance tend to develop slowly and is manageable.

Inheritance mode and properties of fipronil resistance in Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae)

Abstract The dusky cotton bug (DCB), Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae) is one of the most important pests of cotton. Fipronil belongs to phenylpyrazole and is being used against various insect pests. To reduce the resistance to this insecticide, the present study was planned to examine the inheritance mode and preliminary mechanism of resistance to fipronil in DCB. A fipronil selected strain had a 9855-fold level of resistance after 11 generations of selection with fipronil. The median lethal concentration of reciprocal crosses F1 (Fipro-Sel.♂×Lab-Pop♀) and F1-(Fipro-Sel.♀× Lab-Pop♂) showed no significant difference and degree of dominance values were 0.60 and 0.58 for F1 and F1-), respectively, suggesting autosomal and incompletely dominance of resistance to fipronil in fipronil selected strain of DCB. Monogenic model of inheritance revealed polygenic resistance to fipronil. Realized heritability (h2) value was 0.24 for fipronil resistance. The study of synergism indicated that PBO (Piperonyl butoxide) and DEF (S, S-butyl phosphorotrithioateases) did not enhance the toxicity of fipronil on both populations. The study on inheritance mode of fipronil resistance in DCB may help delay the resistance with insecticides.