【Aim】 The toxicity of pyrethroid insecticides can be synergized by organophosphates and carbamates through inhibition of insect carboxylesterase (CarE) activity. This study aims to assess the synergism of 13 organophosphate and carbamate insecticides, and four synergists to beta-cypermethrin for the control of wheat aphids. 【Methods】 The I₅₀ values of 13 insecticides and two inhibitors to the CarE activities in Sitobion avenae and Rhopalosiphum padi wingless adults were determined by using the method of in vitro inhibition. The method of the residual film in glass tube was used to determine the toxicity of each insecticide and its mixture with beta-cypermethrin (3∶1) to both wheat aphid species. Co-toxicity coefficient (CTC) was used to evaluate the synergism. 【Results】 Except for thiodicarb, the other 12 insecticides showed significantly higher inhibiting effect on S. avenae than on R. padi. Dichlorvos mixed with beta-cypermethrin was the strongest inhibitor to the CarE activities of S. avenae and R. padi, with the I₅₀ values of (5.40±0.74)×10^-8 mol/L and (1.41±0.41)×10^-5 mol/L, respectively. The joint-toxicity test of pirimicarb, methomyl, carbosulfan, carbaryl, triazophos, profenofos, malathion, dichlorvos, DEF and TPP respectively mixed with beta-cypermethrin showed that except for profenofos, all the other nine chemicals enhanced the toxicity of beta-cypermethrin to R. padi significantly. And malathion showed the strongest synergistic effect (CTC=467.59); and except for methomyl, profenofos and malathion, the other seven chemicals showed significant synergism to beta-cypermethrin against S. avenae with the CTC range from 146.87 to 626.30, of which the triazophos showed the highest CTC value (626.30). 【Conclusion】 We identified a number of insecticides or synergists with higher toxicity against S. avenae and R. padi when used in combination with beta-cypermethrin, which include pirimicarb, carbosulfan, triazophos, dichlorvos, DEF and TPP. These results provide scientific basis for the effective control of wheat aphids in wheat production.

【Aim】 In order to provide data for efficient management of insecticide resistance of Chilo suppressalis (Walker), we measured the cytochrome P450-mediated 7-ethoxycoumarin-O-deethylase (ECOD) activity in different instars of larval C. suppressalis, and evaluated the time-dependent in vivo effects of piperonyl butoxide (PBO) treatment on the activities of ECOD and carboxylesterase (CarE) in the 4th instar larvae. 【Methods】 By using 7-ethoxycoumarin as the substrate, the ECOD activity in different instar larvae and pupae of C. suppressalis was determined by fluorospectrophotometric analysis. Variations of ECOD and CarE activities in the 4th instar larvae were examined at each hour within 24 hours after treatment topically by PBO (0.69 μg/larva). 【Results】 The ECOD activity in C. suppressalis from the 1st instar larval stage to the pupal stage showed a firstly increasing and then decreasing trend. The ECOD activity increased to the highest level of 14.11±1.01 pmol/mg pro·min in the 4th instar larvae, while decreased to the lowest (1.34±0.11 pmol/mg pro·min) in pupae. PBO exhibited time-dependent effects on the ECOD activity of the 4th instar larvae. As compared with the untreated control, PBO treatment inhibited the ECOD activity during 4-9 h with a maximal inhibition rate of 21% at 6 h, induced its activity during 10-11 h, and then inhibited its activity during 15-17 h. In addition, PBO exposure also affected the CarE activity in the 4th instar larvae, showing inhibition effects during 14-17 h and 20-21 h and induction effects during 10-12 h and 18-20 h after treatment. 【Conclusion】 The ECOD activity varies in different instar larvae and pupae of C. suppressalis. PBO treatment displays time-dependent effects of inhibition or induction on the activities of ECOD and CarE in the 4th instar larvae of C. suppressalis.  

【Aim】 Based on the transcriptome data of the whitefly, Bemisia tabaci, this study aims to systematically analyze the expression profiles of genes encoding detoxification enzymes in thiamethoxam resistant strain, and to focus on discussing the biological significance of developmental stage specific differential expression of these genes. 【Methods】 Thiamethoxam resistant (TH-R) and susceptible (TH-S) strains of B. tabaci were maintained in a greenhouse, and individuals at three developmental stages (egg, the 4th instar nymph and 1 day-old unmated female adult) were collected from the TH-R and TH-S strains. The array design was based on 8 394 ESTs from transcriptome of B. tabaci with putative association with insecticide resistance. By using a custom made microarray, the gene expression in eggs, nymphs and female adults of the TH-R strain of B. tabaci was compared. Nine ESTs were randomly selected for quantitative real-time PCR (qRT-PCR) analysis to validate the microarray response between the TH-R and TH-S strains at three different developmental stages. 【Results】 In the TH-R strain, a total of 3 424 ESTs were differentially expressed between the egg and 4th instar nymphal stages. Among them, 489 ESTs encode detoxification enzymes (carboxylesterase, glutathione S-transferases, cytochrome P450 monooxygenases). Fourteen ESTs (10 ESTs encoding P450s, and 4 ESTs encoding GSTs) were overexpressed in the 4th instar nymphal stage. There were 1 273 ESTs which were differentially expressed between the 4th instar nymphal and female adult stages. Among them, 193 genes encoding detoxification enzymes and nine ESTs encoding P450s showed higher expression level (10-fold) in the female adult stage rather than the 4th instar nymphal stage. The qRT-PCR results revealed that nine ESTs were up-regulated in the TH-R strain at three developmental stages compared to those in the TH-S strain. The EST p_06027 and the EST p_06013 encoding P450s were overexpressed in egg and the 4th instar nymphal stage of the TH-R strain. The ESTs p_05885, p_07806 and the EST p_00988 encoding P450s were highly overexpressed in the 4th instar nymphal stage of the TH-R strain. The ESTs p_05885, p_07806 and the EST p_00988 encoding P450s were highly overexpressed in the 4th instar nymphal stage of the TH-R strain. The ESTs p_05916 and p_00478 had low expression levels in the egg and 4th instar nymphal stages but overexpressed in the female adult stage of the TH-R strain. The ESTs p_00059 and p_00428 were significantly up-regulated in the female adult stage but had low expression level in the other two immature stages of TH-R strain, and the EST p_00059 encoding CYP4C1 with the highest expression level (~15.15-fold) was seen in the female adult stage. 【Conclusion】 The results suggest that the overexpression of CYP4C1 and CYP6B may underlie the resistance to thiamethoxam in B. tabaci. According to the microarray data analyzed, the detoxification enzyme genes are differentially expressed in different developmental stages of B. tabaci, which may be associated with the distribution and effective utilization of energy under the stress of insecticides and also an adaptive mechanism under the environmental selection pressures.

【Aim】 To investigate the relationship between acetylcholinesterase-2 (AChE2) and chlorpyrifos-resistance in Apolygus lucorum. 【Methods】 The AChE2 gene (Al-ace2) was cloned using RACE method. The amino acid polymorphism and the transcription level of Al-ace2 in the chlorpyrifos-resistant (BZ-R) and susceptible (SLF and BZ) strains of A. lucorum were detected. 【Results】 The Al-ace2 gene contains a 1 935 bp open reading frame, which encodes 644 amino acid residues. The deduced amino acid sequence shows the common properties of AChE, such as the catalytic triad amino acids, the characteristic motif ‘FGESAG’ surrounding the active Ser, oxyanion hole and the choline binding sites. T552M amino acid substitution was only found in Al-ace2 in the resistant strain (BZ-R) with the mutation frequency of 5%, but not in the two susceptible strains (SLF and BZ). The amino acid at position 552 is neither conserved nor near to active sites, suggesting that the T552M substitution has much higher possibility to cause polymorphism among individuals than to contribute to chlorpyrifos resistance in A. lucorum. The transcription level of Al-ace1 was approximately three-fold as high as that of Al-ace2 in SLF, BZ and BZ-R strains. The transcription level of Al-ace2 showed no significant difference among the three strains. 【Conclusion】 The results suggest that AChE2 is likely the minor AChE and might not be involved in chlorpyrifos resistance in the BZ-R strain of A. lucorum.

【Aim】 This study aims to investigate the sublethal effects of spinosad on Plutella xylostella after long-term exposure to low concentration of spinosad. 【Methods】 The Sub strain of P. xylostella was continuously selected using the LC₂₅ of spinosad. The susceptibility of the 4th instar larvae of various subpopulations of P. xylostella to spinosad was assayed by leaf dip feeding method, and the change of expression level of nicotinic acetylcholine receptor (nAChR) α subunit gene in the 4th instar larvae of P. xylostella treated with low concentration of spinosad was determined by quantitative real-time PCR. 【Results】 The sensitivity of P. xylostella to spinosad decreased across generations. After selection with the LC₂₅ of spinosad for ten generations (Sub10), the Sub strain developed 2.70-fold resistance compared with the SS strain. Quantitative real-time PCR analysis indicated that the expression level of nAChR α subunit gene decreased with generations and significantly decreased by 32.04% in the Sub10 generation compared to that in the SS strain, and the expression level in the spinosad resistant strain RR (resistance ratio=17.85-fold) was only 37% of that in the SS strain. 【Conclusion】 This multi-generational study found the possible correlation between spinosad susceptibility and the expression abundance of nAChR α subunit gene in P. xylostella, and this is helpful for further understanding of spinosad resistance mechanisms in P. xylostella.  

【Aim】 The oriental fruit fly, Bactrocera dorsalis, is an important worldwide quarantine pest that damages many fruits and vegetables and has developed resistance to many insecticide classes including neonicotinoids. In this study, based on the identification of the cDNA of nicotinic acetylcholine receptor α9 subunit gene in B. dorsalis, we analyzed its molecular characterization and polygenetic relationship, and detected its expression pattern in different developmental stages and adult tissues of B. dorsalis, which will lay the foundation for further understanding the potential function properties and the role of Bdα9 in insecticide resistance in B. dorsalis. 【Methods】 Based on the transcriptome data of B. dorsalis by next-generation sequencing, nicotinic acetylcholine receptor gene sequence was successfully screened, assembled and identified by homologous blast. The full-length cDNA sequence was cloned by using RT-PCR and RACE technology, and bioinformatics analysis software package was used to predict its general biological information. Quantitative real-time polymerase chain reaction was used to investigate the expression profiles of this gene in different developmental stages of the fly and the head, thorax and abdomen of adult B. dorsalis. 【Results】 The nicotinic acetylcholine receptor α9 subunit gene was cloned from B. dorsalis by specific primers designed based on the predicted gene sequence. The full-length cDNA contains 1 486 bp with 1 281 bp of open reading frame encoding 426 amino acids with a predicted molecular weight of 49.1 kD and an isoelectric point of 6.56. The gene was named Bdα9 with the GenBank accession number of JQ178254. The amino acid sequence homology and phylogenetic tree analysis indicated that Bdα9 possesses the typical characteristics of nAChR α subunit, clusters together with Agα9 and Dmβ3, and shares 22%-27% amino acid sequence identity with nAChR α9 subunits from other insects. The qPCR results showed that Bdα9 was expressed in all developmental stages of B. dorsalis. The relative expression level of Bdα9 in the adult was significantly higher than those in the egg, the 2nd instar larva, the 3rd instar larva and the pupa. The expression level of Bdα9 in adult head was the highest and significantly higher than those in adult thorax and abdomen. 【Conclusion】 The nicotinic acetylcholine receptor gene, Bdα9, was identified, and its expression profiles in different developmental stages and adult tissues of B. dorsalis were examined, with the highest expression level in adults and the adult head, respectively, implying that it may play a critical role in the central nervous system of adult.  

【Aim】 The two-spotted spider mite, Tetranychus urticae Koch is an important pest on many agricultural crops worldwide. This study aims to understand the current abamectin resistance and the mutation frequency and expression change of resistance-related genes in different field populations of T. urticae in China. 【Methods】 The resistance of eight field populations of T. urticae to abamectin was determined by vial-leaf dipping (VLD) method, and the gene mutation frequency related to abamectin resistance was detected and the expression levels of genes likely related to abamectin resistance in highly resistant populations were determined by quantitative RT-PCR technique. 【Results】 All the eight field populations of T. urticae tested developed resistance to abamectin. Extremely high resistance to abamectin was found in the populations from Miyun, Beijing (MY-BJ), Weifang, Shandong (WF-SD), Sanya, Hainan (SY-HN), and Changsha, Hunan (CS-HN), with the resistance ratios of 1 526.75-, 481.00-, 315.25-, and 160.75-fold, respectively. In the populations from Tongxian, Beijing (TX-BJ), Haidian, Beijing (HD-BJ), Yuncheng, Shanxi (YC-SX), and Tai’an, Shandong (TA-SD), high resistance was observed with the resistance ratios ranging from 54.38- to 136.38-fold. The mutation frequency of the glutamate-gated chloride ion channel gene GluCl related to abamectin resistance differed in the eight field populations. The highest and lowest mutation frequencies were found in MY-BJ (91.7%) and YC-SX (13.3%) populations, respectively, while moderate mutation frequencies were found in WF-SD and SY-HN populations. There was a significantly positive correlation between resistance level and the mutation frequency of GluCl (P<0.05). The expression levels of GluCl and γ-aminobutyric acid receptor gene (GABAR) in the resistant populations decreased significantly as compared with those in the relatively susceptible strain. 【Conclusion】 Abamectin resistance exists widely in field populations of T. urticae in China. Resistance-related genes with point mutation and the decreased expression are likely relevant to resistance development. Abamectin should be avoided to be applied in controlling T. urticae in fields.

【Aim】 This study aims to assess the current status of insecticide resistance in wheat aphids and the field trial efficacy of some common insecticides to these pests in Shandong Province, so as to screen highly effective and low toxic insecticides to wheat aphids. 【Methods】 Two field populations of wheat aphids were collected from Yanggu and Wenshang in Shandong Province during 2013-2014. Resistance levels of the two field populations to six insecticides (imidacloprid, beta-cypermethrin, omethoate, deltamethrin, pirimicarb and sulfoxaflor) were tested by residual film methods, and the control efficacy of 8 insecticides was evaluated using field trials in 2015. 【Results】 The bioassay results showed that the field populations of Rhopalosiphum padi and Sitobion avenae remained sensitive to the six insecticides in 2013 and 2014, except that the Yanggu population of R. padi developed a low-level resistance to beta-cypermethrin in 2014. Comprehensive evaluation of field efficacy indicated that sulfoxaflor 50% WG, acetamiprid 20% WP, imidacloprid 10% WP and pirimicarb 50% WP had quick-acting property on wheat aphids, and the control efficacy was 76.9%-85.6% at 3 d after treatment. Sulfoxaflor 50% WG, acetamiprid 20% WP, imidacloprid 10% WP, omethoate 40% EC, pymetrozine 25% WP, pirimicarb 50% WP and chlorpyrifos 40% EC had long persistent effects on wheat aphids, and the control efficacy was 80.0%-97.5% at 7 d after treatment. The control efficacy of lambda-cyhalothrin 25 g/L EC against wheat aphids was only 74.9% at 7 d after treatment, significantly lower than that of other insecticides. 【Conclusion】 These results suggest that sulfoxaflor, acetamiprid, imidacloprid, pirimicarb and pymetrozine have high efficacy on wheat aphids, and these insecticides should be used alternately in the control of field wheat aphids.

【Aim】 The white-back planthopper, Sogatella furcifera, is a well-known serious cosmopolitan pest on rice crop. Chemical insecticides have been considered as an effective way for its control. However, field populations of S. furcifera have developed resistance to many insecticides. The objective of the present study is to monitor the insecticide resistance in field populations of S. furcifera in Hubei Province, central China, so as to provide useful information for reasonable applications of these insecticides. 【Methods】 Resistance of four field populations of S. furcifera collected form rice fields of Putuan of Ezhou, Changgang of Ezhou, Wen’an of Zhijiang and Nankou of Shishou during 2011-2014 to eleven commonly used insecticides was detected by rice stem dipping method. 【Results】 The field populations of S. furcifera have developed medium-level resistance to buprofezin ［resistance ratio (RR)=13.0-38.6］. Moreover, the field populations tested showed no resistance (susceptible) to medium-level resistance to imidacloprid (RR=2.6-15.4), no resistance (susceptible) or low-level resistance to clothianidin  (RR=3.0-7.0), dinotefuran (RR=2.5-7.0), acetamiprid (RR=3.3-8.2) and thiamethoxam (RR=2.1-6.9), and maintained susceptible to nitenpyram (RR=2.2-4.9), isoprocarb (RR=2.0-4.6) and etofenprox (RR=1.8-4.0). In addition, the field populations of Changgang (2011 and 2012) and Putuan (2012) remained susceptible to pymetrozine (RR=3.1-4.9), while other populations developed moderate-level resistance to pymetrozine (RR=15.2-91.0). All populations were susceptible or showed low-level resistance to chlorpyrifos (RR=1.7-8.5) except that the field populations of Changgang (2013 and 2014) showed moderate-level resistance to chlorpyrifos (RR=15.6 and 10.1, respectively). 【Conclusion】 Due to the obvious increase in resistance to imidacloprid, buprofezin and pymetrozine, resistance monitoring is urgently needed, and applications of these insecticides should also be limited to prevent or delay further increase of insecticide resistance in S. fercifura.

【Aim】 The brown planthopper, Nilaparvata lugens, occurs in many parts of Asia and has developed a high degree of resistance to several chemical classes of common insecticides. The objective of this study is to assess the current status of insecticide resistance in field populations of N. lugens, so as to supply effective insecticide resistance management strategies to prevent or delay the development of insecticide resistance in N. lugens. 【Methods】 The susceptibility of the field populations of N. lugens from rice fields of Zaoyang City, Xiaogan City, Wuxue City, Wuhan City, and Ezhou City in Hubei Province to 11 insecticides was assayed by rice stem dipping method. 【Results】 The field populations of N. lugens have developed high-level resistance to imidacloprid ［the resistance ratio (RR)=101.8-1 239.4)］ and buprofezin (RR=15.9-1 326.3), medium- to high-level resistance to thiamethoxam (RR=24.9-146.5), medium-level resistance to clothidianidin (RR=9.9-16.5), dinotefuran (RR=13.5-15.9), ethiprole (RR=18.3-60.4), chlorpyrifos (RR=17.4-29.8) and isoprocarb (RR=13.9-46.0), low-level resistance to acetamiprid (RR=5.1-9.9), no resistance (susceptible) or low-level resistance to thiacloprid (RR=3.9-7.1), and no resistance (susceptible) to etofenprox (RR=1.3-4.9). 【Conclusion】 It is suggested that imidacloprid and buprofezin should still be suspended for the control of N. lugens and the application frequencies of pymetrozine must be limited. Etofenprox, however, could be an alternate or rotational insecticide for them.  

【Aim】 The objective of this research is to assess the resistance of the brown planthopper, Nilaparvata lugens (St?l) to conventional insecticides in Guizhou, southwestern China. 【Methods】 The resistance to six insecticides (imidacloprid, thiamethoxam, isoprocorb, clothianidin, acetamiprid and ethofenprox) in field populations of N. lugens collected from three rice growing regions (Huangping, Tongzi, and Kaiyang) in Guizhou Province during 2013-2015 was assayed by rice dipping method. 【Results】 Substantial variations of the resistance level to different insecticides existed in N. lugens populations from Guizhou. Compared with the susceptible population of N. lugens, the three field populations have developed moderate-level resistance to imidacloprid, thiamethoxam, isoprocorb and clothianidin during 2013-2015, with the resistance ratios of 21.88-95.38, 10.91-69.36, 13.00-57.23 and 23.11-39.54-fold, respectively, while these field populations were still sensitive to acetamiprid and ethofenprox, with the resistance ratios of 0.47-0.75-fold and 0.41-0.85-fold, respectively. 【Conclusion】 The results suggest that the resistance of N. lugens in Guizhou to imidacloprid and thiamethoxam might increase quickly with the wide use of these insecticides in the main rice planting areas. The results provide important guidance for the adjustment of insecticide types and application strategies against the brown planthopper in Guizhou.  

【Aim】 Sucking insect pests have become the major cotton pests since transgenic Bt cotton was widely planted in the northern areas of China. The objective of this study is to make clear the status of insecticide resistance of the major cotton pests, so as to advise farmers to scientifically control insect pests. 【Methods】 Dynamic changes in insecticide resistance of Helicoverpa armigera, Aphis gossypii and Apolygus lucorum from Qiuxian County in Hebei Province, Binzhou City in Shandong Province, Xihua County in Henan Province were monitored from 2013 to 2015 using leaf dipping method and topical application method, respectively. 【Results】 The resistance levels of H. armigera to phoxim and cyhalothrin increased to over 20-fold, and H. armigera became resistant to emamectin benzoate, with a resistance ratio of 10-fold. The resistance ratios of A. gossypii to omethoate, cypermethrin and imidacloprid were over 100-fold. For A. lucorum, although its resistance to imidacloprid increased from susceptible to over 10-fold in the Qiuxian and Binzhou populations, the resistance ratios to malathion and methomyl remained below 10-fold in all the detected populations. However, the Binzhou population of A. lucorum showed 95-fold resistance to cyhalothrin. According to the resistance monitoring results, a rotation-based resistance management strategy was established and implemented in the cotton demonstration areas in Binzhou City, Shandong Province. Compared with conventional farmer-decisive farm, the cotton demonstration areas obtained good benefits, characterized by a 3-fold reduction of pesticide application, a 7.53% yield increase, and an extra income of 109.16 Yuan per 667 m². 【Conclusion】 Insecticide resistance of the major cotton insect pests in the northern areas of China has developed, and rotation-based resistance management strategies are needed.

【Aim】 Aphis gossypii is easy to produce resistance to insecticides because of its short growth cycle and high reproduction rate. This study aims to clarify the levels and mechanisms of imidacloprid resistance in A. gossypii in the main cotton production areas of China. 【Methods】 Different populations of A. gossypii were collected from fields in Haidian of Beijing (BJ), Langfang (LF) and Handan (HD) of Hebei, Dezhou (DZ) of Shandong, Xuchang (XC) of Henan, and Kuitun (KT) and Akesu (AKS) of Xinjiang. Leaf-dipping method was used to determine the resistance levels of A. gossypii to imidacloprid. The activities of three detoxification enzymes ［mixed function oxidase (MFO), carboxylesterase (CarE) and glutathione S-transferase (GST)］ and acetylcholinesterase (AchE) in different A. gossypii populations were assayed. And the mutation of target gene (nAChR β1 subunit gene) was also detected. 【Results】 The BJ, XC and HD populations of A. gossypii were still susceptible to imidacloprid, while the LF, AKS, DZ and KT populations exhibited moderate levels of resistance to imidacloprid, with the resistance ratios of 22.6-, 26.3-, 53.5- and 61.1-fold, respectively. The activities of MFO, CarE and GST in the AKS and KT populations were significantly higher than those in the BJ susceptible population. The activities of MFO, CarE and GST in the AKS population were 1.7-, 1.6- and 1.5-fold, and those in the KT population were 1.8-, 1.7- and 1.5-fold as high as those in the BJ population, respectively. But there was no significant difference in acetylcholinesterase (AchE) activities among the AKS, KT and BJ populations. A single point mutation in the nAChR β1 subunit causing an arginine to threonine substitution (R81T) observed in LF, AKS, DZ and KT populations was associated with the imidacloprid resistance in A. gossypii. 【Conclusion】 The results suggest that enhancement of MFO, CarE and GST activities and the mutation (R81T) of nAChR β1 subunit might confer resistance to imidacloprid in A. gossypii.

【Aim】 The common cutworm, Spodoptera litura (Fabricius), is one of major agricultural pests all over the world. In this study we evaluated the resistance level of S. litura to insecticides in five major vegetable growing areas of Hunan province and determined the relationship between the resistance to indoxacarb and the activities of detoxification enzymes in S. litura, aiming to offer the theoretical basis for the control of this pest. 【Methods】 The resistance to 10 insecticides in S. litura populations from five districts of Hunan Province from 2014 to 2016 was assayed using a standard leaf dip bioassay method. Indoxacarb was used to select a resistant strain under 40%-70% selection pressure. The activities of CarE, GST and PNOD in the 3rd instar larvae of the susceptible and indoxacarb-resistant strains were tested. 【Results】 Compared with the susceptible strain, the resistant strain of S. litura obtained 26.9-220.2-fold resistance to organophosphates, 68.3-890.8-fold resistance to carbamates, 21.0-267. 2-fold resistance to pyrethroids and 5.2-53.4-fold resistance to relatively novel insecticides including emamectin, abamectin, indoxacarb and chlorfenapyr. After 14 continuous generations of selection with indoxacarb, the selected population obtained 26.43-fold resistance compared with its unselected population. The activities of CarE, GST and PNOD in the selected strain were 2.86, 1.01 and 1.83-fold higher than those in the unselected strain, respectively. 【Conclusion】 S. litura has developed different levels of resistance to the tested insecticides, and the enhancement in the activities of CarE and PNOD is an important mechanism for the increased resistance of S. litura to indoxacarb.

【Aim】 The rice planthopper (BPH), Nilaparvata lugens, is one of the important non-target insect pests of the Bt rice, and many insecticides could induce the resurgence of N. lugens. This study aims to understand the resurgence potential of N. lugens on Bt rice and non-Bt rice treated by different nitrogen regimes. 【Methods】 The indices of ecological fitness (nymphal duration, nymphal survival rates, female adult weight, the number of eggs laid per female and egg hatchability) of N. lugens treated with different concentrations of deltamethrin (0, 1, 3 and 6 mg/L) were evaluated on Bt rice lines (T1C-19 and T2A-1, harboring  cry1C* and cry2A* gene, respectively) and its parental non-Bt rice (MH63) applied with different application levels of nitrogen fertilizer (0, 100 and 250 kg N/hm²). 【Results】 The nymphal survival of N. lugens treated with the high concentration of deltamethrin (6 mg/L) was significantly lower than that in the untreated control, while the number of eggs laid per female was significantly higher than that in the untreated control. ANOVA results indicated that the interaction between nitrogen fertilizer and deltamethrin significantly affected the nymphal survival rate, female adult weight, number of eggs laid per female and egg hatchability. The fecundity did not significantly differ when N. lugens nymphs were reared on the Bt and non-Bt rice lines treated with deltamethrin under the nitrogen regime of 0 kg N/hm², while significantly increased with the increase of deltamethrin concentration on the rice lines under the nitrogen regimes of 100 kg N/hm² and 250 kg N/hm². The ecological fitness of N. lugens increased as the nitrogen fertilizer application level increased. The nymphal duration shortened and the nymphal survival rates, female adult weight, the number of eggs laid per female and egg hatchability increased as the nitrogen fertilizer application level increased. The values of the ecological fitness indices were not significantly different on the Bt and non-Bt rice lines treated with the same concentration of deltamethrin under the same nitrogen regime. 【Conclusion】 The results indicate that nitrogen fertilizer application can promote the resurgence of N. lugens induced by deltamethrin on Bt rice lines T2A-1 and T1C-19, and this effect does not differ between Bt rice lines and non-Bt rice.

Long noncoding RNAs (lncRNAs) are a novel class of non-protein coding transcripts longer than 200 nt and regarded as a kind of key regulatory molecules which could regulate gene expression at many different levels including transcriptional and post-transcriptional levels. In this article, the characteristics, classification and mode of actions of lncRNAs were summarized, and the recent advances of lncRNA research in entomology were reviewed. In the last five years, a huge amount of lncRNAs have been identified from eight insects including Drosophila melanogaster, Plutella xylostella and Nilaparvata lugens, providing important foundation for further exploration of lncRNA function in insect development. At the same time, lncRNA mediated insecticide resistance has become an emerging field of insecticide toxicology, so the very recent advances in lncRNAs involved in insecticide resistance were also reviewed.

【Aim】Hainan province is one of the major winter melon and vegetable production bases in China. However, due to the suitable environmental conditions, plant diseases and insect pests could occur all the year round, leading to a tremendous amount of pesticide consumption. This has resulted in potential risk in agricultural product quality and safety. This study investigated the current status of pesticide application and control efficiency in winter melon and vegetable pest control, and analyzed the behavior choice logic and influencing factors of agricultural producers’ pesticide application, so as to provide an effective reference for plant disease and insect pest management. 【Methods】 By means of questionnaire investigation, field survey and tracking survey, we investigated and analyzed the main plant diseases and insect pests, control situation, pesticide types, pesticide application dosage and control efficiency. 【Results】 There are many kinds of plant diseases and insect pests in winter melons and vegetables in Hainan (nearly 60 species, including 16 major insect species and 19 major plant disease species), which have long occurrence cycle and cause serious damage. The actual application dosage of pesticide has been far higher than the recommended dosage in Hainan. A huge variety of pesticides in a tremendous amount were applied in every growing season. The investigation on 25 growers showed that 86 pesticides had been applied in winter melon and vegetable growing season with the accumulated application frequency of 988 times. The most commonly used pesticides are abamectin, imidacloprid and so on. And the farmers lack of the awareness of safe use of pesticides, and blindly choose the type and dosage of pesticides. We proposed for the first time the pesticide application index as a parameter to measure the application dosage of pesticides in different crops, plant diseases and insect pests, which would be more objective to reflect the actual application dosage in the field. 【Conclusion】 Based on the investigation and analysis, comments and suggestions on pesticide use in Hainan winter melon and vegetable production are given.