Insecticide resistance in Helicoverpa armigera in South India

Cypermethrin, quinalphos, endosulfan and methomyl were bioassayed against strains of Helicoverpa armigera collected from field crops in Andhra Pradesh and Tamil Nadu, South India, during the 1989-90 and 1990-91 cropping seasons. In 1989, high levels of resistance to cypermethrin were recorded in strains from cotton in the cotton-growing regions of Guntur, Andhra Pradesh and Coimbatore, Tamil Nadu, and from pigeon pea near Hyderabad. There was no evidence for resistance to quinalphos or methomyl at that time. In 1990-91 sampling was more extensive and although tolerance to cypermethrin was lower than the previous season, the survey indicated that pyrethroid-resistant populations were present throughout much of Andhra Pradesh. Tolerance to quinalphos had increased slightly in 1990-91, while resistance to methomyl had increased substantially, particularly in the cotton-growing area of Guntur. Endosulfan tolerance had increased slightly compared to strains tested in 1986-88 in an earlier study. The geographic and temporal variations in severity of pyrethroid resistance in H. armigera in Andhra Pradesh are believed to arise because of dynamic interactions between local selection pressure and immigration of resistant and susceptible moths at certain times of the year.     

Insecticide resistance in the bollworm,Helicoverpa armigera from Indonesia

Helicoverpa armigera collected from cotton growing areas of South Sulawesi, Indonesia in 1987 and early 1988 were resistant to cypermethrin. It is suggested that the 86-fold resistance to cis-cypermethrin in 1987 and the 65-fold resistance to cis/trans-cypermethrin in 1988 are consistent with this being a major cause of failure to control the insects in cotton in this area. The second laboratory generation showed a 20-fold resistance to fenvalerate. The larvae collected in 1988 additionally had a 203-fold resistance to DDT and a 5.6-fold resistance to endosulfan. The results are discussed in relation to the fact that this is a further region in which Helicoverpa armigera has developed resistance to a number of pyrethroids.     

Insecticide resistance in Tephritid flies

Tephritid flies attack a large variety of fruits, which constitute highly-priced commodities in many countries. Insecticides have been used extensively for their control.Although resistance development in fruit flies has not kept pace with that in other insects, possibly due to their high mobility and tendency for wide spatial dispersal, recent studies have indicated that selection pressure has now reached the point where resistance is detectable in the field and control may therefore become problematic. The status of resistance to the commonly used insecticides in the most significant Tephritid pests, such as the Mediterranean fruit fly Ceratitis capitata, the oriental fruit fly Bactrocera dorsalis, the olive fly Bactrocera oleae and the melon fly Bactrocera cucurbitae, is reviewed. Emphasis has been placed on the resistance mechanisms that have been elucidated at the biochemical and molecular level. Prospects for using this knowledge alongside genomic information in Tephritidae to develop novel strategies of potential practical importance for resistance management are discussed.     

三种增效剂对棉铃虫增效作用

用３个不同地区的棉铃虫田间种群分别测定了３种增效剂对３种杀虫剂的增效作用。结果表明ＰＢ对氯氟氰菊酯,ＤＥＦ对辛硫磷,ＰＢ和ＴＰＰ对灭多威增效较好,而且棉铃虫的抗性水平越高,增效剂的增效作用越突出。     

Insecticide resistance in vector mosquitoes in China

Because of their special behaviour, physiology and close relationship with humans, mosquitoes act as one of the most important vectors of human diseases, such as filariasis, Japanese encephalitis, dengue and malaria. The major vector mosquitoes are members of the Culex, Aedes and Anopheles genera. Insecticides play important roles in agricultural production and public health, especially in a country with a huge human population, like China. Large quantities of four classes of insecticides, organochlorines, organophosphates, carbamates and pyrethroids, are applied annually to fields or indoors in China, directly or indirectly bringing heavy selection pressure on vector populations. The seven major species of vector mosquito in China are the Culex pipiens L. complex, C. tritaeniorhynchus Giles, Anopheles sinensis Wied., A. minimus Theobald, A. anthropophagus Xu & Feng, Aedes albopictus (Skuse) and Ae. aegypti L., and all have evolved resistance to all the above types of insecticide except the carbamates. The degree of resistance varies among mosquito species, insecticide classes and regions. This review summarizes the resistance status of these important vector mosquitoes, according to data reported since the 1990s, in order to improve resistance management and epidemic disease control, and to communicate this information from China to the wider community.     

棉铃虫卵在棉株上的分布与查卵方法的改进

江苏沿江棉区棉铃虫在棉田发生以三、四代为主,其中四代是主害代。查准田间卵量对决策防治及准确反映当年棉铃虫发生量等具有重要意义。国家标准《棉铃虫测报调查规范》规定三代查棉株群尖和嫩叶上的卵量（实际调查中发现漏查率较高）,而对四代查卵未有明确规定。为此,...     

Resistance to synthetic pyrethroids in the bollworm,Heliothis armigera from Andhra Pradesh,India

Helio this armigera collected in October 1987 from Juzzuru in the coastal cotton growing district of Krishna in Andhra Pradesh (Eastern India) were highly resistant to cypermethrin and fenvalerate and moderately resistant to endosulfan. Prior to this, in 1986, H. armigera in the Hyderabad area were resistant to DDT but not to pyrethroids or endosulfan. By late 1987 these latter populations were highly resistant to pyrethroids and mildly resistant to endosulfan. Concurrently, the resistance to DDT increased. It is suggested that resistant moths from the east coast migrated downwind in a northwesterly direction with the prevailing winds which occur at that time of year. The level of pyrethroid resistance in H. armigera infesting pigeon-pea and chick-pea fields around Hyderabad increased steadily up to March 1988. These results are discussed with special reference to the resistance mechanisms likely to be involved.     

Identification of the sex pheromone of the cotton bollworm,Heliothis armigera,in Israel

The composition of the female sex pheromone ofHeliothis armigera in Israel has been identified, with four main compounds detected: Z-9-hexadecenal (3%), Z-11-hexadecenal (87%), hexadecanal (4%), and hexadecanol (6%). The first two aldehydes are the essential components of the sex pheromone ofH. armigera.     

Pyrethroid resistance mechanisms in Australian Helicoverpa armigera

In 1983, at the onset of pyrethroid resistance in Australian Helicoverpa armigera, three resistance mechanisms were identified. They were: a strong nerve insensitivity (Super-Kdr), penetration resistance (Pen), and a factor which was overcome by piperonyl butoxide (PBO). Super-Kdr nerve insensitivity appeared to be a major cause of pyrethroid resistance and contributed to high-order resistance (> 100-fold). From 1987 to 1990, to monitor the effect of the Australian Helicoverpa insecticide resistance management strategy on insecticide resistance, we conducted a survey of the frequencies of these mechanisms in field-collected H. armigera. The relative importance of the Pen and Pbo mechanisms in resistant H. armigera have increased but Pen and Pbo confer only low order (～ 20-fold) resistance. We found no evidence of the 1983 Super-Kdr mechanism in the latest samples, but, instead, found another distinct Kdr-type mechanism. This mechanism was correlated with very low-order nerve insensitivity and was of little toxicological significance. The impact of the Helicoverpa insecticide resistance management strategy on pyrethroid resistance in H. armigera is discussed.     

高邮市棉铃虫发生危害近况及综合治理对策

棉花是高邮地区主要农作物之一,棉铃虫为棉花主要害虫,年发生4代,个别年份可见不完全5代.20世纪90年代初至中期连年重发,90年代后期,随着综合治理技术示范和推广以及转基因抗虫棉种植面积扩大,棉铃虫发生程度呈逐年下降趋势.但2000年以来棉铃虫发生面积仍占种植面积100%,发生程度为轻至中等发生,在不防治的情况下,一般造成减产30%左右,特大发生年份产量损失达60%～70%.     

Insecticide resistance in disease vectors of public health importance

Vector-borne diseases are a global problem--a trend that may only increase if global temperature rises and demographic trends continue--and their economic and social impact are enormous. Insecticides play a vital role in the fight against these diseases by controlling the vectors themselves in order to improve public health; however, resistance to commonly used insecticides is on the rise. This perspective outlines the major classes of disease vector control agents and the mechanisms of resistance that have evolved, arguing that effective resistance management strategies must carefully monitor resistance in field populations and use combinations of the limited modes of action available to best effect. Moreover, the development of novel insecticide classes for control of adult mosquitoes and other vectors becomes increasingly important.     

增效剂Pbo、TPP对田间棉铃虫抗性种群增效作用研究

对西华田间棉铃虫种群，Ｐｂｏ能显著地增加氰戊菊酯、高效氯氰菊酯、灭多威的毒力，大幅度地降低其致死中量，ＴＰＰ对两种拟除虫菊酯杀虫剂也能表现一定的增效作用；对甲基对硫磷、甲胺磷，无论是Ｐｂｏ还是ＴＰＰ其增效作用均十分有限。增效剂对杀虫剂的增效效果与棉铃虫对该杀虫剂的抗性水平及其主导抗性机制密切相关。     

灭多威、辛硫磷及其混剂对棉铃虫的毒力测定和田间药效试验

采有点滴法测定灭多威、辛硫磷及其混剂对棉铃虫的毒力，结果表明，灭多威与辛硫磷混配，各个配比均行增效作用，其中以1：2．6(有效成分)的配比增效作用最大，毒性比率和共毒系数分别为1．58和151．41。田间试验表明，灭多威与辛硫磷的混剂对棉铃虫有较好的防治效果，室内结果在田间试验中得到验证。     

Insecticide resistance compromises the control of Aedes aegypti in Bangladesh

BACKGROUND

With no effective drugs or widely available vaccines, dengue control in Bangladesh is dependent on targeting the primary vector Aedes aegypti with insecticides and larval source management. Despite these interventions, the dengue burden is increasing in Bangladesh, and the country experienced its worst outbreak in 2019 with 101 354 hospitalized cases. This may be partially facilitated by the presence of intense insecticide resistance in vector populations. Here, we describe the intensity and mechanisms of resistance to insecticides commonly deployed against Ae. aegypti in Dhaka, Bangladesh.

RESULTS

Dhaka Ae. aegypti colonies exhibited high-intensity resistance to pyrethroids. Using CDC bottle assays, we recorded 2–24% mortality (recorded at 24 h) to permethrin and 48–94% mortality to deltamethrin, at 10× the diagnostic dose. Bioassays conducted using insecticide–synergist combinations suggested that metabolic mechanisms were contributing to pyrethroid resistance, specifically multi-function oxidases, esterases, and glutathione S-transferases. In addition, kdr alleles were detected, with a high frequency (78–98%) of homozygotes for the V1016G mutation. A large proportion (≤ 74%) of free-flying and resting mosquitoes from Dhaka colonies survived exposure to standard applications of pyrethroid aerosols in an experimental free-flight room. Although that exposure affected the immediate host-seeking behavior of Ae. aegypti, the effect was transient in surviving mosquitoes.

CONCLUSION

The intense resistance characterized in this study is likely compromising the operational effectiveness of pyrethroids against Ae. aegypti in Dhaka. Switching to alternative chemical classes may offer a medium-term solution, but ultimately a more sustainable and effective approach to controlling dengue vectors is required. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Insecticide resistance in Musca domestica L. from Eastern England

Strains of houseflies were obtained from a refuse tip and 34 farms selected at random from Eastern England in 1984. Resistance was assessed to four insecticides that had been in use for fly control in the UK. Dose-response data were obtained by topical application of the insecticides and, in addition, a resistance test method was used in which flies were allowed to feed on sugar coated with either methomyl or azamethiphos. For both methods, the knock-down (KD) after 48 h was used as a measure of response. The ranges of resistance factors for the topical application method were, for methomyl, 1·1–15·9 at KD₅₀ and 2·1–17·0 at KD₉₅; for azamethiphos, 2·2–36·9 at KD₅₀ and 4·5–88·2 at KD₉₅; for pyrethrins + piperonyl butoxide, 0·9–6·8 at KD₅₀ and 1·4–13·4 at KD₉₅; and for permethrin, 1·7–34·8 at KD₅₀ and 2·2–112·5 at KD₉₅. The ranges of the resistance factors for the feeding tests were, for methomyl, 2·1–39·8 at KD₅₀ and 2·4–64·0 at KD₉₅, and, for azamethiphos, 5·6–51·7 at KD₅₀ and 8·8–92·0 at KD₉₅.     

烟芽夜蛾囊泡病毒3h株3h-122基因于棉铃虫幼虫体内的转录表达分析

本文构建了烟芽夜蛾囊泡病毒3h株(HvAV-3h)第122个基因(3h-122)的原核表达载体并制备多克隆抗体?利用蛋白免疫印迹?RT-PCR?免疫组织化学染色等技术检测3h-122的转录表达时相以及组织特异性?结果表明, 3h-122编码大小16.1 kD的结构蛋白(3H-122)?HvAV-3h感染棉铃虫幼虫后3 h开始检测到3h-122的转录并稳定持续至第168 h?3H-122在棉铃虫感毒后24 h至168 h可持续检测到其表达?此外, 3H-122主要在脂肪体组织中表达?本研究为阐明囊泡病毒结构蛋白的功能及其在囊泡病毒致病机制中的作用奠定了基础?     

Insecticide resistance in the tropical bedbug Cimex hemipterus

Insecticide resistance in the bedbug Cimex hemipterus was investigated using 4211 bedbugs collected from three districts of Sri Lanka. Insecticide bioassays were carried out with discriminating dosages of deltamethrin, permethrin, DDT, malathion, and propoxur. Activity levels of insecticide metabolizing enzymes and the insecticide target site acetylcholinesterase were monitored using biochemical assays. Percentage survivals after DDT, malathion, and propoxur exposure were 41-88%, 18-64%, and 11-41%, respectively. For deltamethrin and permethrin, KT₅₀/KT₉₀ (time to knock-down 50%/90% of the population) values were 0.5-24/1.0-58 and 1.3-10/2.5-47 h, respectively. Both elevated esterase and malathion carboxylesterase mechanisms were present in bedbug populations. Monooxygenase levels were heterogeneous. Organophosphate and carbamate target site acetylcholinesterase, was insensitive in 29-44% of the populations. High DDT resistance was probably due to glutathione S-transferases. Malathion carboxylesterases are mainly responsible for high malathion resistance. High tolerance to both DDT and pyrethroids suggests the presence of ‘kdr’ type resistance mechanism in one population.     

Laboratory Studies on Host Preference and Insecticide Resistance of the Cotton Bollworm,Heliothis obsoleta F.1

Pupae of the cotton bollworm, Heliothis obsoleta F., from the northern part of Iran (Gorgan and Gonbad areas) were brought to the laboratory and used as the breeding source for bollworms. The larvae were reared on soybean plants for 8 generations under laboratory conditions of 60±5 % RH and 27±2 °C. To test host preference, the adults of both sexes were released into wooden cages where they were able to freely select their host. The females laid more eggs on soybean (before and at blooming) compared to cotton (before and after blooming) and maize (before and after stem extension). Seven and 14-day-old larvae were treated with different doses of Supracide and Thiodan by topical application. Altogether, 3,000 larvae were used for this experiment and from the data collected, LD 50 values were calculated. It was found that, as the age doubled from 7 to 14 days, the LD 50 value for Supracide increased from 0.6 mg/g to 0.92 mg/g. For Thiodan, the corresponding increase during this period was from 0.52 mg/g to 1.50 mg/g. Fat body content was measured using Soxhlet apparatus and its correlation with LD 50 values was determined. Fat bodies represented 2.1 and 2.5% of the body weight in 7 and 14-day-old larvae, respectively.