Influence of three diets on susceptibility of selected insecticides and activities of detoxification esterases of Helicoverpa assulta (Lepidoptera: Noctuidae)

The oriental tobacco worm, Helicoverpa assulta Guenée, is one of the most destructive pests of tobacco and peppers in China. We determined the susceptibility of H. assulta reared on an artificial diet, chili pepper and tobacco to four insecticides (fenvalerate, phoxim, methomyl, indoxacarb) under laboratory conditions associated with the activities of acetylcholinesterase (AChE), carboxylesterase (CarE) and glutathione S-transferase (GST) in its larvae. H. assulta larvae that were fed with chili pepper were more susceptible to fenvalerate, indoxacarb, and phoxim than those that were fed with tobacco and the artificial diet, but not to methomyl. The larvae that were fed with chili pepper were 3.65-, 2.49-, 1.92- and 2.44-fold more susceptible to fenvalerate, phoxim, methomyl, and indoxacarb than those fed with tobacco, respectively. The AChE activities of H. assulta larvae that were fed with chili pepper and tobacco were 2.12 and 1.07 μmol mg⁻¹ 15 min⁻¹, respectively, almost 2-fold difference. The CarE activity of H. assulta larvae that were fed with chili pepper, tobacco and the artificial diet was 4.12, 7.40 and 7.12 μmol mg⁻¹ 30 min⁻¹, respectively. Similarly, the GST activities of H. assulta larvae that were fed with chili pepper, tobacco and the artificial diet was 52.02, 79.37 and 80.02 μmol mg⁻¹ min⁻¹, respectively. H. assulta larvae that were fed with chili pepper were more resistance to the tested insecticides. The low activities of AChE and the high activities of CarE and GST lead to H. assulta become more susceptible to the tested insecticides.     

Patterns of resistance to organophosphate insecticides in field populations of Helicoverpa armigera in Pakistan

The pattern of organophosphate resistance in field populations of Helicoverpa armigera (Hübner) was monitored in Pakistan from 1994 through 1997 using an IRAC leaf-dip method. Generally, moderate to high resistance was found to an orthophosphorate, monocrotophos and to a dithiophosphorate, ethion. Resistance to the commonly used thiophosphorates, chlorpyrifos and profenofos, was very low during 1994 and 1995 but showed an upward trend during 1996 and 1997. Resistance factors to the other thiophosphorates such as quinalphos, parathion-methyl, methamidophos and triazophos remained very low. Baseline lethal concentrations for ethion, methamidophos and triazophos were at least four to five times higher than those for the other organophosphates tested, suggesting their low intrinsic efficacy against H armigera. © 1999 Society of Chemical Industry     

Comparative biology of Mallada desjardinsi (navas) and Chrysoperla congrua (walker) (Neuroptera: Chrysopidae), predators of Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) and aphis gossypii (glover) (Homoptera: Aphididae) on cotton in eastern Tanzania

The developmental biology of Mallada desjardinsi (Navas) and Chrysoperla congrua (Walker) on the American bollworm, Helicoverpa armigera and the cotton aphid, Aphis gossypii was studied in the laboratory at 28–32°C. Total larva! periods of M. desjardinsi and C. congrua on H. armigera eggs were 14.4 and 14.8 days respectively. However, when reared on A. gossypii larval periods of M. desjardinsi and C. congrua were 14.9 and 13.5 days respectively. When reared on H. armigera 52.9% and 25% respectively of third instars of M. desjardinsis and C. congrua sp. died before pupation. However, when reared on A. gossypii 82.6% and 46.9% respectively of third instars of M. desjardinsi and C. congrua died before pupation. Thus, H. armigera eggs and A. gossypii nymphs were both adequate but not optimal diets for chrysopid larval development. The number of prey consumed by M. desjardinsi and C. congrua increased with instar. Total larval consumption of H. armigera by M. desjardinsi and C. congrua was determined to be 135.5 and 169.8 eggs respectively. However, total larval consumption of A. gossypii by M. desjardinsi and C. congrua was found to be 189.0 and 171.8 nymphs respectively. Because of its longer larval period, and higher consumption of A. gossypii, M. desjardinsi would be better suited for use against A. gossypii than C. congrua. In contrast, C. congrua whose consumption of H. armigera was higher than that of M. desjardinsi although their larval periods were similar, would appear promising for control of H. armigera.     

Toxicity of biorational insecticides: activity against the green peach aphid, Myzus persicae (Sulzer)

The relationship between dose for each of four biorational insecticides (pyrethrins, neem extract, capsiacin extract, insecticidal soap) and mortality of the green peach aphid (Myzus persicae) was determined using a laboratory bioassay. These insecticides were toxic to aphids and paired mixtures of the insecticides provided synergistic activity as measured by aphid mortality under the laboratory bioassay conditions. Capsiacin extracts were found to provide low levels of mortality alone but acted synergistically in mixtures with the other insecticides and provided higher than expected levels of mortality. Activity as determined in the laboratory for each insecticide was not evident under field-use conditions in five separate experiments. Under field conditions and using common application methods, these insecticides did not provide significant levels of control of aphids.     

Insecticide Resistance Management of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) and its effect on pests and yield of cotton in North India

Journal of Plant Diseases and Protection - An insecticide resistance management (IRM) strategy was devised and evaluated for the management of cotton bollworm, Helicoverpa armigera (Lep.,...     

Methylparathion- and carbofuran-induced mitochondrial dysfunction and oxidative stress in Helicoverpa armigera (Noctuidae: Lepidoptera)

The cotton bollworm, Helicoverpa armigera is a polyphagous pest of several crops in Asia, Africa, and the Mediterranean Europe. Organophosphate and carbamate insecticides are used on a large-scale to control Helicoverpa. Therefore, we studied the effect of methylparathion and carbofuran, an organophosphate and carbamate insecticide, respectively, on oxidative phosphorylation and oxidative stress in H. armigera larvae to gain an understanding of the different target sites of these insecticides. It was observed that state III and state IV respiration, respiratory control index (RCI), and P/O ratios were inhibited in a dose-dependent manner by methylparathion and carbofuran under in vitro and in vivo conditions. Methylparathion and carbofuran inhibited complex II by ∼45% and 30%, respectively. Lipid peroxidation, H₂O₂ content, and lactate dehydrogenase (LDH) activity increased and glutathione reductase (GR) activity decreased in a time- and dose-dependent manner in insecticide-fed larvae. However, catalase activity was not affected in insecticide-fed larvae. Larval growth decreased by ∼64% and 67% in larvae fed on diets with 100 μM of methylparathion and carbofuran. The results suggested that both the insecticides impede the mitochondrial respiratory functions and induced lipid peroxidation, H₂O₂, and LDH leak, leading to oxidative stress in cells, which contribute to deleterious effects of these insecticides on the growth of H. armigera larvae, along with their neurotoxic effects.     

Genetics of Heliothis and Helicoverpa resistance to chemical insecticides and to Bacillus thuringiensis

Genetic linkage maps of Heliothis virescens and Helicoverpa armigera are being used to identify and characterize resistance-conferring genes. The insensitive acetylcholinesterase conferring resistance to organophosphorus insecticides and the insensitive sodium channel conferring resistance to pyrethroids have both been mapped in H. virescens. The linkage mapping approach permits a genetic dissection of resistance, even when the mode of action and lethal target are not precisely known, such as for the insecticidal toxins from the bacterium Bacillus thuringiensis (Bt). We have identified and mapped a major Bt-resistance locus in a strain of H. virescens exhibiting up to 10000-fold resistance to Cry1Ac toxin and are currently developing a linkage map for H. armigera with a set of ‘anchor’ loci to facilitate comparison with H. virescens. Both species are currently experiencing their first significant selective pressure in the field by transgenic cotton expressing Cry1Ac, and timely identification of resistance mechanisms and their underlying genetic basis will be essential in successfully managing the Bt resistance that will eventually appear. ©1997 SCI     

Short-term toxicity of insecticides residues to key predators and parasitoids for pest management in cotton

The cotton ecosystem comprises various arthropod pest and natural enemies with simultaneous occurrence irrespective of growing region. The use of insecticides with reduced impact on natural enemies is a major goal to conserve them and, therefore, to reduce populations of arthropod pests. The survival of twelve key natural enemies for cotton pest management exposed to dried residues using the highest and lowest recommended rates representing old and new insecticides recommended to control cotton pests (chlorantraniliprole, chlofernapyr, spinosad, lambda-cyhalotrin, methidathion, pymetrozine, and thiamethoxam) was determined. The study included parasitoids [Aphelinus gossypii Timberlake, Bracon vulgaris Ashmead, Lysiphlebus testaceipes (Cresson), Telenomus podisi (Ashmead), Trichogramma pretiosum (Riley)] and predators [Hippodamia convergens Guérin-Méneville, Euborellia annulipes (Lucas), Podisus nigrispinus (Dallas), Solenopsis invicta Buren), Orius insidiosus (Say), Chrysoperla externa Hagen and Eriopis connexa (Germar)], with two different cohorts for these last two species. All natural enemies exposed to methidathion exhibited 100% mortality. Thiamethoxam, lambda-cyhalothrin and chlorfenapyr also caused high mortality of P. nigrispinus, S. invicta, H. convergens, O. insidiosus and all tested parasitoids. Among the natural enemies, E. annulipes exhibited high survival when exposed to all tested insecticides, except methidathion. Chlorantraniliprole and pymetrozine caused overall lower impact on the natural enemies tested followed by spinosad; hence, they are options for cotton pest management. Furthermore, the outcomes highlight the implication of knowing the background susceptibility of the species tested when addressing the impact of insecticides on natural enemies.     

江西省裳夜蛾亚科昆虫名录（鳞翅目;夜蛾科）

本文记述了江西省裳夜蛾亚科的昆虫24个属71种昆虫,其中2种江西新纪录。     

Resistance selection and biochemical characterization of spinosad resistance in Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

A Helicoverpa armigera population was collected from Shandong province, China. After 15 generations of selection in the laboratory, the H. armigera strain developed more than 20-fold resistance to spinosad. At LD₅₀ level, no significant cross-resistance was found between spinosad and chlorpyrifos, methomyl, avermectin and chlorfenapyr except for fenvalerate with a low cross-resistance of 2.4-fold. However, LD₉₉ values of fenvalerate against the parental and resistant strains were not different significantly. After inhibitors were used, spinosad resistance could be partially suppressed by piperonylbutoxide (PBO) and triphenylphosphate (TPP), but not by diethylmaleate (DEM). Activities of p-nitroanisole O-demethylase (ODM) developed to 8.26-fold compared with the parental strain, but no obvious changes were found in activities of carboxyl esterase (CarE) and glutathione-S-transferase (GST). The results indicated that resistance to spinosad in the cotton bollworm might be associated with an increase in cytochrome P450 monooxygenase.     

Mating,longevity, fertility and fecundity of the cotton leaf-worm,Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

The mechanisms adopted to ensure mating success, fertility and fecundity ofS. littoralis were studied. The male moths usually mate only once a night but they mate repeatedly during most of their life span, and practically all their spermatophores are equally efficient for inseminating a female. Although females are also multiple maters, one spermatophore is sufficient for a female to lay fertile eggs throughout her life with no reduction in potential fecundity. While a male may mate 5.3 times, on the average, a female may mate only 2.3 times. As a pronounced decrease in pheromone release occurs after mating, a repeat mating by a female will occur only after most neighboring competitive virgin females have been inseminated. A male may mate therefore with 5.3 different females, all of which will be thoroughly inseminated. The female moth is ready to mate just after emergence and at any time throughout her life. If mating is delayed the preoviposition period is greatly prolonged and eggs are saved to be laid later, after mating, as fertile eggs. Delay in egg laying due to delayed insemination does not result in reduced fecundity as it is compensated for by prolonged longevity. Even if mating is greatly delayed and occurs after egg laying has already begun, the potential reduction in reproduction is not very great, due to the low daily egg-laying rate and the increased longevity of unmated females. It appears unreasonable to expect any tendency toward reduction of egg production with a decrease in the ratio of adult males in a population; for this purpose the control of males must be essentially complete. Therefore, a behavioral control program by mass trapping ofS. littoralis males is unlikely to be economically feasible.     

The effects of diet on the detection of resistance to Cry1Ac toxin in Australian Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

The effects of raw or heat-denatured soybean flour in an artificial diet on the detection of Cry1Ac resistance in Helicoverpa armigera were examined. Resistant neonate larvae reared on denatured soybean flour diet showed resistance factors of 7980 and 16,901 at the LC₅₀ and LC_99.9 levels, respectively. By comparison, resistance could not be detected in neonate larvae reared on raw flour diet. Third instar larvae reared on denatured flour diet showed resistance factors of 322 and 21,190 at the LC₅₀ and LC_99.9 levels. Resistance was not detected in third instar larvae reared on raw flour diet. There was 68% survival of resistant neonate larvae on Bollgard II cotton leaf feeding assays, compared to 100% mortality in a susceptible strain. We conclude that detection of CRY1Ac resistance in H. armigera from Australia can be masked, if an artificial diet gives chronic exposure to potent, protease inhibitors present in raw soy flour.     

Toxicity of Mixtures of Bacillus thuringiensis with Endosulfan and Other Insecticides to the Cotton Boll Worm Helicoverpa armigera

In the laboratory, low concentrations of Bacillus thuringiensis Berliner (B.t.), as ‘Dipel’ 2X applied (at about the LC₅) to cotton leaves enhanced the activity of endosulfan and reduced resistance to endosulfan from approximately seven fold to two fold in neonate larvae of Helicoverpa armigera (Hubner). Low (LC₅) concentrations of endosulfan also increased the toxicity of B.t. Both endo-sulfan and B.t. increased the toxicity of the stomach poison cryolite to H. armigera. This increased toxicity was not observed where B.t./endosulfan combinations were applied topically to larvae or where B.t. was combined with organophosphorus or pyrethroid insecticides which are considered primarily to be contact toxicants. Mixtures of B.t. and endosulfan applied at equitoxic concentrations were less toxic than similar concentrations applied alone.     

青翅蚁形隐翅虫在棉田捕食性天敌中的地位与作用

2001年调查结果表明,青翅蚁形隐翅虫发生量在淮北棉田捕食性天敌中占8.1%,居第四位;与棉田主要害虫具有较强的追随关系;对棉铃虫、棉蚜、棉叶螨具有较强的聚集攻击效应;是淮北棉田优势种天敌之一。     

溴甲烷熏蒸对桃蛀果蛾的毒力作用

对溴甲烷熏蒸处理桃蛀果蛾结果进行机率值法分析,推算出在25℃温度条件下溴甲烷熏蒸处理1.5h和2h,达到桃蛀果蛾Carposina sasakii Matsumura幼虫死亡率99%的浓度时间乘积(CT值)分别为43.79g·h/m3和46.77 g·h/m3;15℃和10℃温度条件下熏蒸处理3h,达到桃蛀果蛾幼虫死亡率99%的溴甲烷浓度分别为50.84 g·h/m3和118.55 g·h/m3.研究表明,溴甲烷熏蒸对桃蛀果蛾幼虫的毒性作用随着溴甲烷熏蒸浓度的增加而增加,相同熏蒸剂浓度条件下,随着温度升高,溴甲烷熏蒸效果明显增加.     

Seven invasive owlet moths (Lepidoptera: Noctuidae) in Israel and their potential parasitoids (Hymenoptera: Chalcidoidea)

Invasive tropical Noctuidae pest species collected in Israel included Spodoptera mauritia (Boisduval), Trichoplusia vittata (Wallengren), Anomis flava (Fabricius), Anomis sabulifera (Guenée), Earias vittella (Fabricius), Earias biplaga Walker, and Earias cupreoviridis (Walker). All seven noctuid species were rare and sporadically present only along the coastal plain. Possible reasons for this type of distribution are discussed. Abundance was greatest in May with smaller peaks present in February–March and September. Several common parasitoid species – Elasmus flabellatus (Fonscolombe), Elasmus nudus (Nees) and Elasmus viridiceps Thomson (Hymenoptera: Eulophidae), with potential as biological control agents for tropical noctuids, are detected in Israel.     

Development of the Multi-nucleocapsid Nucleopolyhedroviruses (MNPVs) Infectious to Loopers (Lepidoptera: Noctuidae: Plusiinae) as Microbial Control Agents

A number of the members of the Noctuidae (subfamily Plusiinae) are polyphagous insects that infest a variety of economically important crops world-wide. These hosts include but are not limited to cotton, vegetable and field crops and also such specialty crops as mint. Many of these crops require multiple applications of chemical pesticides to protect them from various loopers and other economic pests. One proposed alternative to the use of chemical pesticides to protect these crops is the development of insect-specific viruses of the family Baculoviridae. Hundreds of these viruses of the genus Nucleopolyhedrovirus have been isolated, many from economically important Lepidoptera. The advent of the discovery that some of these viruses may have a broad host range increased the interest in the development of them as microbial agents throughout the world. The broad host range (over 30 species in some cases) provided the possibility to control not only one species, but a complex of lepidopterous pests infesting specific or multiple crops. From the 1960s to the present, extensive basic and applied research has been conducted on the multi-nucleocapsid (MNPV) forms within which a broad host range appears to be characteristic. Of these, the virus isolated from the alfalfa looper, Autographa californica (Speyer) (AcMNPV) has been the most studied, particularly as related to microbial control. Two of the viruses isolated from loopers have been registered in the USA. Although efficacy has been demonstrated for loopers, there is a paucity of data on the other important species that may simultaneously infest looper hosts. Because of their relatively slow action, the viruses will probably be used in integrated programs with chemical pesticides applied during critical periods of high population pressure. Further research needs to be conducted to establish efficacy for other hosts, improved production methods either in vivo or in vitro, increased field persistence as related to timing and frequency of applications, and finally the utility of genetically engineered MNPVs as microbial pesticides. The potential of these organisms has been demonstrated and new developments are being made to increase the overall efficiency and economics of their use. These improvements can only increase interest in use of the baculoviruses in pest management systems for loopers and other pests.     

Temperature-dependent development of Agrotis ipsilon (Lepidoptera: Noctuidae) and its stage transition models

The black cut worm Agrotis ipsilon (Hufnagel) is a destructive crop pest worldwide and a typical cut worm damaging plant parts below the soil surface, which requires a thorough phenological prediction of the target stage for proper management. Temperature is an essential factor affecting the phenology and dynamics of insect populations. So, this study was conducted to evaluate the temperature-dependent development of A. ipsilon fed on Kimchi cabbage (Brassica campestris) in a wide range of temperatures (10 to 40 ℃) in the laboratory. The linear and nonlinear relationship between temperature and development rate (1/development time) was analyzed. The lower threshold temperatures (LT) for eggs, larvae, and pupae were estimated to be 12.1 °C, 9.6 °C, and 11.2 °C, respectively, with thermal constants (degree days for development completion) of 31.3, 342.2, and 181.3 DD at each stage, respectively. Additionally, the thermal constant for tracking the phenology of each stage was determined using a common LT of 10.4 ℃: 40.3 DD for eggs, 315.6 DD for larvae, and 199.6 DD for pupae. Consequently, we provided newly the stage transition models for all stages of A. ipsilon using two basic components of the nonlinear development rate and distribution models to simulate the proportion of individuals shifted from one stage to the next stage. These models in their current form will be useful for constructing a population model for A. ipsilon in the future. Furthermore, the variation in the development time of A. ipsilon reported in previous studies was discussed using 95% confidence limits of the estimated line of our nonlinear models.

     

Synthetic bis- and mono-chalcones with insecticide effects on Spodoptera frugiperda (Lepidoptera: Noctuidae)

Abstract

This is the first report on the antifeedant, toxic and nutritional effects produced by the synthetic chalcones on the lepidopteran Spodoptera frugiperda followed by structure-activity relationship. Bis (5a-c) and mono (8a-d) chalcones have been synthesized via Claisen-Schmidt condensation and have been purified and characterized. The mono chalcones 8b and 8d displayed toxic effects on early larval instars when incorporated to the larval diet at 100?µg per g of diet (40 and 60%, respectively) and low adults emergency with malformations leading to death. The remaining chalcones 8a, 8c, 5a, 5b and 5c do not displayed toxic effects at the same dose. The evaluation of nutritional indices indicated that 8a and 8c were the only tested chalcones to produce decrease in the growth rate and to reduce the efficiency with which larvae converted ingested food into biomass.     

Selection and characterization of spinosad resistance in Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae)

The cross-resistance and biochemical mechanism of the beet armyworm, Spodoptera exigua (Hübner), to spinosad was studied in the laboratory. S. exigua population were collected from Shanghai suburb. After five generations of selection, the resistance of S. exigua to spinosad increased 345.4 times compared with the susceptible strain. There was no cross-resistance between spinosad and fenvalerate, phoxim, methomyl, abamectin, and cyfluthrin. When the inhibitors, PBO, TPP, DEF, and DEM were used as synergist in the susceptible strain and resistant strain, the synergistic ratio was 0.7-, 0.5-, 1.0-, and 0.6- fold for the susceptible strain, and 9.8-, 1.5-, 2.6-, and 1.5-fold for the resistant strain, respectively. The results revealed that PBO had significant synergistic effect on the resistant strain. The activity in vitro of microsomal-O-demethylase and glutathione S-transferase in the resistant strain was 5.2- and 1.0-fold of the susceptible strain, respectively. The results implied that microsomal-O-demethylase might be important in conferring spinosad resistance in the S. exigua population.