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1.
Petroleum ether, acetone, water and aqueous extract of Pedalium murex L. (Pedalaceae) leaves, root and fruit were tested against fourth instar larvae of the tobacco cutworm, Spodoptera litura (Fabr.) under laboratory conditions using leaf dip method. Larval mortality; larval, pupal and adult periods; pupal weight, pupation and adult emergence; larval and pupal deformities of S. litura were recorded. All the tested solvent extracts of P. murex were effective against S. litura life stages by causing mortality in a dose dependent manner. However, the efficacy was more significant with respect to acetone (leaf and root) and petroleum ether (root) at higher concentrations (0.8%) which leads to 100% larval mortality. The water and aqueous extracts of root caused 86.6 and 88.0% larval mortality respectively at 4% concentration. Among the plant parts tested, root had more importance followed by leaf and fruit. Plant extracts extended the larval, pupal and adult periods; reduced the pupal weight, pupal and adult emergence and caused larval–pupal deformities. Total life time was highly prolonged in acetone extracts of P. murex root. Though all the extracts were found to have insecticide activity, acetone and petroleum ether extracts of P. murex root can be used as an effective alternative to modern synthetic insecticides. Bioactive principles from these extracts can be isolated, identified and integrated in S. litura management.  相似文献   

2.
Effects of elevated atmospheric CO2 (elevated CO2 vs. ambient CO2) and temperature (+0.67–0.79°C vs. ambient temperature) on the developmental life cycle of Spodoptera litura and the food utilization of the fourth‐instar larvae fed on soybean (resistant cultivar Lamar vs. susceptible landrace JLNMH) grown in open‐top chambers were studied from 2013 to 2015. The results indicated that: (i) compared with ambient CO2, elevated CO2 significantly prolonged the duration of larva and pupa, and adult longevity; significantly decreased the pupation rate, pupal weight, fecundity, the relative growth rate (RGR), efficiency of conversion of ingested food (ECI) and efficiency of conversion of digested food (ECD); and increased the relative consumption rate (RCR) and approximate digestibility (AD). (ii) Compared with ambient temperature, elevated temperature significantly shortened the duration of larva and pupa; significantly decreased the pupal weight; and increased the RGR, RCR, ECD and ECI. (iii) Compared with the susceptible soybean accession JLNMH, the resistant soybean cultivar Lamar significantly prolonged the duration of larva and pupa; significantly decreased the pupation rate, pupal weight, adult longevity, fecundity and RGR, RCR and AD; and increased the indexes of ECD. (iv) At elevated temperature, S. litura fed on resistant vs. susceptible cultivars showed opposite trends in the RGR, RCR, AD, ECD and ECI. In addition, elevated temperature under elevated CO2 significantly decreased the RGR (2014), ECD (2013 & 2014) and ECI (2013) and increased the AD (2013 & 2014) compared with other treatment combinations when S. litura fed on Lamar. Future climatic change of temperature and CO2 concentration would likely affect growth and food utilization of S. litura, with increased food intake, but the reduced fecundity may compensate for the increased food consumption, resulting in no significant reduction in insect‐induced yield loss in soybean production. Nevertheless, use of insect resistant soybean cultivars will aid in ecological management of S. litura and reduce the insecticide load in soybean production.  相似文献   

3.
Nutritional indices, development rates, percent dry weights and total lipids were determined in gypsy moth larvae (Lymantria dispar L.) reared on a high wheat germ (HWG) diet or diets prepared from lyophilized, ball-milled oak or pine foliage as the only source of dietary nitrogen (N). With regard to both total and proteinaceous N content, HWG diet>oak diet>pine diet. All nutritional indices measured were significantly lower in second instars fed pine diet vs. oak diet. Protein supplementation of pine diet with either casein or ovalbumin to bring total N up to the level present in oak diet resulted in small increased in approximate digestibility (AD) and effciency of conversion of ingested food (ECI), but relative growth rate (RGR) remained unaffected. The low RGR of larvae fed pine diet (unsupplemented or protein supplemented), as compared to those fed HWG or oak diet, was accompanied by significantly lower larval percent dry weight and percent total lipid. In contrast, RGR, larval percent dry weight and total lipid values were comparable in second instars fed HWG or oak diet. Insects reared from the first through the final instar on oak diet exhibited lower pupal weights compared to those reared on HWG. Casein addition to oak diet generally resulted in even more extended larval development times and further reduced pupal weights, but wheat germ addition to oak diet did not alter development rates and caused an increase in pupal weights.  相似文献   

4.
The new 2,3‐secoaromadendrane 1 , together with the known compounds plagiochilines A and M ( 2 and 3 , resp.), fusicogigantone A ( 4 ), and 1,4‐dimethylazulene ( 5 ) were isolated from an Argentine collection of the liverwort Plagiochila bursata. Structures were elucidated by extensive 1D‐ and 2D‐NMR studies. Compounds 2 and 4 , incorporated to the larval diet at 100 μg per g of diet, reduced the larval growth of Spodoptera frugiperda (Lepidoptera: Noctuidae) by 66±29% and 25±8% and produced 55 and 75% larval mortality at early instars and 20 and 25% pupal mortality, respectively. Treatment with compound 2 also produced abdomen and wing malformation in adults leading to impossibility to mate.  相似文献   

5.
The potential of the entomogenous fungus Metarhizium anisopliae as a microbial control agent for vine weevil (Otiorhynchus sulcatus) larvae was examined on a range of outdoor hardy nursery stock species. A curative application of M. anisopliae conidia (5× 108 conidia l‐1compost) reduced larval numbers by 62% on Skimmia japonica ’Rubella’ and by up to 43% on Viburnum plicatum ’Mariesii’. Four M. anisopliae isolates were examined and all reduced the larval populations on both species. However, the reductions were only significant with strains 159–83 and 100–82 on S. japonica ’Rubella’ and 100–82 on V. plicatum ’Mariesii’. Larval development on two other species (Hydrangea macrophylla ’Blue Wave’ and Thuja plicata ’Zebrina') which had been treated with 0.05% Triton X‐100 (the control treatment) was very poor and therefore it was not possible to determine whether or not the fungal drench had any effect. The experiment was repeated in the following year at two different sites, East Mailing and Littlehampton, using a prophylactic drench of two M. anisopliae isolates on a greater number of plant species. Strain 275–86 was more effective than 159–83 on all species at East Mailing, with the exception of V. davidii. The difference was less pronounced at Littlehampton and the results from the two isolates were similar. Larval control was highly variable and species dependent with a reduction in larval numbers ranging from zero to 96% and zero to 90% at East Mailing and Littlehampton respectively. The larval populations in pots treated with Triton X‐100 were also highly variable, ranging from zero (Chaemaecyparis lawsoniana ’Stardust’ Dianthus ’Maria’ Escallonia ’Crimson Spire’ and Pittosporum tenuifolium ’Gamettii') to 17.8 larvae per pot (Ribes nigrum ’Baldwin ‘). The results indicate the potential of M. anisopliae and demonstrate the complexity of plant‐weevil‐fungus interactions.  相似文献   

6.
The sugarcane borer, Diatraea saccharalis (F.) (Lepidoptera: Crambidae), is a dominant maize borer pest and a major target of Bacillus thuringiensis (Bt)‐maize in Louisiana and the Gulf Coast area of Texas (USA). Growth and development of D. saccharalis on non‐toxic diet, diet treated with three low concentrations (0.01, 0.05, and 0.1 μg g?1) of Cry1Ab toxin, and on non‐Bt maize plants were compared for five insect genotypes: a Bt‐susceptible strain (BT‐SS), a Cry1Ab‐resistant strain (BT‐RR), a back‐crossed and re‐selected resistant strain (BT‐R’R’), and two F1 progeny of the BT‐SS and BT‐R’R’ strains. Fitness of the five genotypes was examined by infesting neonates on diet with/without Cry1Ab toxin in the laboratory and on intact non‐Bt maize plants in the greenhouse. Biological parameters measured were neonate‐to‐pupa development time and pupation rate, larval survival, larval and pupal weight, and sex ratio. Larvae of BT‐SS and BT‐R’R’ on non‐toxic diet and non‐Bt maize plants grew normally and there were no significant differences between the two strains in all measured parameters, suggesting a lack‐of‐fitness cost of the Cry1Ab resistance in D. saccharalis. Except for the development time on non‐Bt diet, all other parameters on both non‐Bt diet and non‐Bt maize plants were similar among the five genotypes. Larval development of BT‐SS was significantly affected on diet treated with Cry1Ab toxin at 0.05 and 0.1 μg g?1, whereas the effect to BT‐RR and BT‐R’R’ was not significant. Pupal weight and sex ratio reared on Cry1Ab‐diet were similar and there were no significant differences among the five genotypes. Neonate‐to‐pupation rate decreased as Cry1Ab concentrations increased but the decrease was more significant for BT‐SS than for the other four genotypes. The lack‐of‐fitness costs of Bt resistance in D. saccharalis imply a greater challenge in managing Bt resistance for this maize borer species.  相似文献   

7.
Diet quality influences organismal fitness within and across generations.For herbivorous insects,the transgenerational effecets of diet remain relatively underexplored.Usinga3×3×2 factorial experiment,we evaluated how N enrichment in parental diets of Neolemd abbreviata(Larcordaire)(C oleoptera:Chrysomelidae),a biological control agent for Tradescantia fluminensis Vell.(Commelinaceae),may influence life history and performance of Fi and F2 offspring under reciprocal experiments.We found limited transgenerational effects of foliar nitrogen variability among life-history traits in both larvae and adults.Larval weight gain and mortality were responsive to parental diet contrary to feeding damage,pupal weight and duration taken to pupate.There were significant parental diet x test interactions in larval feeding damage,weight gain,pupal weight and time to pupation.Generally,offspring from parents under high N plants performed better even under low N test plants.Adult traits including oviposition selection,feeding weight and longevity did not respond to the efects of parental diet nor its interaction with test diet as was the case in the larval stage.However,the main efects of test diet were more important in determining adult performance in both generations suggesting limited sensitivity to parental diet in the adult stage.Our results show conflicting responses to parental diet between larvae and adults ofthe same generation among an insec species with both actively feeding larual and adult life stagee These tranegeneratinonal efferte,or lack thereof,may have implications on the field performance of N.abbrevita under heterogencous nutritional landscapes.  相似文献   

8.

Nyctemera annulata Boisduval was reared in the laboratory at 26±1°C and 50 ±5% RH on a host plant, ragwort (Senecio jacoboea L.), and on an artificial diet. On ragwort the average life cycle of 34 days embraced a larval period of 24 days, with up to 6 larval instars, and a pupal period of 9–11 days, depending on whether pupation occurred at the 5th or 6th instar. On the artificial diet the larval period of 56 days, involving up to 10 instars, was followed by a pupal period of 9 days, for an average life cycle of 65 days.  相似文献   

9.
The efficacy of one new modified and two old meridic diets on Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) for rearing six successive generations was studied. Duration of larval development for insects fed on the modified diet was considerably shortened as most of them went through only five stadia before pupation, while the per cent pupation and per cent eclosion were relatively higher than on other diets. The lowest pupal mortality (6.33 ± 0.13%) was recorded in the F1 generation reared on the modified diet, whereas the highest pupal mortality (19.49 ± 0.15%) was observed in insects reared on a natural diet in the F6 generation. Blending of chickpea Cicer arietinum L. and red kidney bean Phaseolus vulgaris L. flours with tomato paste proved highly favorable for adult reproduction. These results suggest that the vitality of the tomato fruitworm did not decline obviously after rearing on a modified diet for several generations.  相似文献   

10.
In insects, glutamine synthetase (GS), a key enzyme in the synthesis of glutamine, has been reported to be associated with embryonic development, heat shock response, and fecundity regulation. However, little is known about the influence of GS on postembryonic development. In this study, we demonstrate that blocking the activity of GS in the oriental fruit fly (Bactrocera dorsalis) with use of a GS‐specific inhibitor (L‐methionine S‐sulfoximine), led to a significant delay in larval development, pupal weight loss, and inhibition of pupation. We further identify cloned and characterized two GS genes (BdGS‐c and BdGS‐m) from B. dorsalis. The two GS genes identified in B. dorsalis were predicted to be located in the cytosol (BdGS‐c) and mitochondria (BdGS‐m), and homology analysis indicated that both genes were similar to homologs from other Dipterans, such as Drosophila melanogaster and Aedes aegypti. BdGS‐c was highly expressed in the larval stages, suggesting that cytosolic GS plays a predominant role in larval development. Furthermore, RNA interference experiments against BdGS‐c, to specifically decrease the expression of cytosolic GS, resulted in delay in larval development as well as pupal weight loss. This study presents the prominent role played by BdGS‐c in regulating larval development and suggests that the observed effect could have been modulated through ecdysteroid synthesis, agreeing with the reduced expression of the halloween gene spook. Also, the direct effects of BdGS‐c silencing on B. dorsalis, such as larval lethality, delayed pupation, and late emergence, can be further exploited as novel insecticide target in the context of pest management.  相似文献   

11.
To clarify differences in pupal cold hardiness and larval food consumption between overwintering and non‐overwintering generations of the common yellow swallowtail, Papilio machaon, we reared larvae from the Osaka population under photoperiods of 16 h light : 8 h dark (LD 16:8) (long day) or LD 12:12 (short day) at 20°C. We examined the relationship between food consumption and weight during the final larval stadium and pupae, and measured the pupal supercooling point (SCP). Although the ratio of assimilation to consumption did not differ significantly between photoperiods, the ratio of assimilation to pupal weight differed significantly between individuals reared under long and short days. All diapausing pupae were brown, whereas 56% of non‐diapausing pupae were green with the remainder brown. The mean pupal body length (L), dorsal width (W1) and lateral width (W2) were larger in non‐diapausing than in diapausing pupae, and the W1/L and W1/W2 ratios differed significantly between non‐diapausing and diapausing pupae. SCP was approximately –20°C and did not differ among pupae 5, 15 and 30 days after pupation under long‐day conditions. However, under short‐day conditions, mean SCP gradually decreased, stabilizing at approximately –24 to –25°C by 30 days after pupation. After freezing, some diapausing pupae emerged as adults, whereas all non‐diapausing pupae died. Both egestion and assimilation were greater under long‐day conditions. The results revealed that pupae of this papilionid exhibit seasonal polyphenism in physiological and morphological traits. Energy from food appears to be expended on increasing cold hardiness in the overwintering generation and on reproduction in the non‐overwintering generation.  相似文献   

12.
A new biocontrol formulation system was devised that does not require sterile conditions during preparation. It involves mixing vermiculite and powdered wheat bran with wet or dry fermentor biomass of Trichoderma spp. or Gliocladium virens, moistening with 0.05 N HCl, and drying the mixture. Before application to soil, the preparation (VBA‐FB) is activated by re‐moistening with 0.05 N HCl and incubated at room temperature for 2–3 days to stimulate development of young hyphae of the biocontrol fungus. Populations of biocontrol fungi proliferated to greater than 107 colony‐forming units (cfu) per g of soil when activated VBA‐FB was added to soil. In soil artificially infested with Rhizoctonia solani, seven isolates of the 14 studied added as VBA‐FB reduced survival and 12 reduced saprophytic growth of the pathogen. Of these, two isolates of T. hamatum (TRI‐4, Tm‐23) and one of T. harzianum (Th‐87) were the most effective. Preparations formulated with either wet or dry biomass effectively reduced pathogen survival, but activated VBA‐FB was more effective than non‐activated VBA‐FB. Storage of VBA‐FB at 25°C for 24 weeks before activation reduced viability of isolates considerably more than storage at 5°C for 24 weeks. In addition, VBA‐FB stored at 5°C before activation more effectively reduced survival of R. solani than VBA‐FB stored at 25° C. Survival of R. solani was reduced by activated VBA‐FB applied to several soil types (sandy loam, sandy clay loam, clay). Some nitrogen fertilizers increased the efficacy of VBA‐FB preparations of several isolates.  相似文献   

13.
Exposure of Plodia interpunctella and Sitotroga cerealella to sublethal concentrations of Dipel 2X® (Bacillus thuringiensis var.kurstaki‐HD‐1)with its spores and endotoxin crystals led to an increase in the sum of larval‐pupal duration. A decrease in moth emergence, egg production and fertility was observed with increase of Dipel 2X concentration, while the longevity of the moths was not affected by treatment. Sublethal concentrations of β‐exotoxin (ABG‐6162 A) had no significant effect on the sum of larval—pupal duration of either insect species. Percentage of moth emergence decreased with the increase of β‐exotoxin concentrations. The longevity of both male and female adults of P. interpunctella and of females of S. cerealella were shorter at high concentrations. Egg production in P. interpunctella was reduced by all concentrations of the β‐exotoxin, and hatching of eggs was reduced by concentrations of 15 ppm and above.  相似文献   

14.
以棉铃虫Helicoverpa armigera (Hübner)室内敏感品系和田间品系为寄主,研究了亚致死浓度的Bt杀虫蛋白对中红侧沟茧蜂Microplitis mediator (Haliday)生长发育的影响。结果表明: 当寄主一直取食,或者在被寄生前12小时开始取食含Bt杀虫蛋白浓度为0,0.5,1.0, 2.0,4.0,8.0 μg/g的饲料时,与对照相比,中红侧沟茧蜂的卵-幼虫历期延长,茧重和成虫体重降低,成虫寿命缩短,但对茧期没有明显影响。Bt杀虫蛋白能有效抑制两个棉铃虫品系幼虫的生长,显著降低棉铃虫蛹重;当Bt蛋白浓度为4.0 μg/g时,显著降低棉铃虫化蛹率。用转双基因抗虫棉SGK321(表达Cry1A+CpTI蛋白)饲喂两个棉铃虫品系初孵幼虫,室内品系的第2、3、4和5天校正死亡率分别为48.5%、87.8%、96.6%和 95.8%,显著高于田间品系(30.9%、59.6%、80.9%及86.1%)。本研究表明,不论是田间品系还是室内品系,棉铃虫取食含Bt杀虫蛋白的饲料后,对中红侧沟茧蜂的生长发育都具有显著的负面作用。  相似文献   

15.
Interactions between the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), its larval parasitoid Microplitis mediator (Haliday) (Hymenoptera: Braconidae), and the Cry1Ac toxin of Bacillus thuringiensis Berliner were evaluated under laboratory conditions. The growth of H. armigera larvae was delayed and its pupal rate and pupal weight decreased when they were fed on a diet containing Cry1Ac toxin. Due to the lowered growth rate of the host larvae, the time available for parasitization of H. armigera by M. mediator increased when the host larvae were reared on a diet containing Cry1Ac toxin at concentrations of 0.5, 1, 2, and 4 µg g?1. The longevity of female and male parasitoids was not significantly affected when newly emerging wasps fed on honey solutions containing three different concentrations of Cry1Ac toxin (125, 250, and 500 µg ml?1). When female parasitoids were fed on honey solutions containing Cry1Ac, their offsprings’ egg and larval development period, pupal weight, length of pupation, adult weight, and adult longevity did not change significantly in most of the treatments compared with controls. When the female parasitoids parasitized host larvae that had been fed on a diet containing 0.5, 1, 2, 4, and 8 µg g?1 Cry1Ac toxin, their offsprings’ eggs and larvae were significantly delayed. Their pupal weight, adult weight, and adult longevity were also significantly less than controls.  相似文献   

16.
Liquid larval diets have been developed for several tephritid fruit flies including Queensland fruit fly, Bactrocera tryoni (Frogatt) (Q‐fly). In liquid diets, wheat germ oil (WGO) is usually added to improve performance in some quality parameters of reared flies, especially flight ability. However, for some flies, other plant oils may be more readily available, cheaper or produce flies of superior performance. In the present study, four alternative types of plant oils – rice bran, canola, vegetable, and sesame – were incorporated into a fruit fly liquid larval diet to replace the currently used wheat germ oil and their efficacy on the quality parameters of reared Q‐fly was compared to diets containing wheat germ oil or no oil. The quality parameters included: total pupal yield (N), pupal recovery (%), larval duration (days), pupal weight (mg), adult emergence (%), adult fliers (%), rate of fliers (%), sex ratio (%), F1 egg/female/day and egg hatching (%). There were significant differences among treatments in performance of Q‐fly. Vegetable oil appeared better in terms of total pupal yield, percentage of pupal recovery, percentage of adult emergence, percentage of fliers, mean egg/female/day and % F1 egg hatch compared with other oil treatments, especially from that of WGO treated diet. The result suggests that WGO can be substituted with rice bran and vegetable oil to improve the liquid larval diet for rearing of B. tryoni, with vegetable oil being the best replacement.  相似文献   

17.
The plant chemical azadirachtin was administered, either in artificial diet or by oral injection, to fifth instar larvae of the tobacco budworm, Heliothis virescens (Fabr.). At a dietary concentration of 0.03125 ppm, azadirachtin significantly reduced the amount of diet consumed and the weight gained by the larvae. Higher dietary concentrations (0.25 and 0.5 ppm) were necessary to reduce the efficiency of larval conversion of digested and ingested food, respectively. However, the approximate digestibility increased at the dietary concentration of 0.25 ppm.Orally injected azadirachtin (0.25 and 0.5 μg) delayed moulting to the pupal stage, produced defective pupae or adults, and inhibited development to the adult stage. Higher doses (5.0 and 10.0 μg) reduced the pre-pupal weight loss normally associated with pupation, and completely inhibited pupation. At the critical dose of 1.0 μg (the minimal dose that disrupted development to the pupal stage), azadirachtin had less of an effect on older than on younger larvae. Larvae injected on the first day of the fifth instar failed to pupate, whereas approx 40% of those injected on subsequent days pupated.The results suggest that azadirachtin affects H. virescens in a manner similar to other tested species of insects. The significance of these results, especially regarding hormonal events in the insects, is discussed.  相似文献   

18.
19.
Nondiapause pupae of Papilio machaon L. exhibit pupal colour diphenism comprising green–yellow and brown–white types. To understand the regulatory mechanism underlying the control of pupal colouration in P. machaon, the effect of environmental cues on diapause and nondiapause pupal colouration is investigated. When larvae reared under short‐day and long‐day conditions are allowed to pupate in sites with a smooth surface and a yellow background colour, all diapause pupae exhibit a brown–white type and 89.5% of nondiapause pupae exhibit a green–yellow type, respectively. With rough‐surface pupation sites, all diapause pupae exhibit brown–white and intermediate types, whereas a large proportion of nondiapause pupae exhibit brown–white and intermediate types, although some exhibit a green–yellow type. When extracts prepared from the head‐thoracic and thoracic‐abdominal regions of larval central nervous systems are injected into the ligated abdomens of P. machaon short‐day pharate pupae, all recipients exhibit a brown–white colouration. Furthermore, when each extract is injected into the ligated abdomen of Papilio xuthus L. short‐day pharate pupae with orange‐pupa‐inducing factor activity, recipients injected with the head‐thoracic extract exhibit the brown type, whereas those injected with the thoracic‐abdominal extract exhibit an orange colour. The results indicate that the response to the environmental cues of pupation site in P. machaon changes according to the photoperiodic conditions experienced during larval stages, and that at least two hormonal factors producing brown–white pupae are located in the larval central nervous system, with the secretion of these factors being regulated by the recognition of environmental cues in long‐day larvae.  相似文献   

20.
Unexpected pathogens from the environment represent considerable risk for humans with impaired health. We examined the occurrence of itraconazole tolerant micromycetes in soil and in maize products. Five concentrations of itraconazole (2.5–12.5 μg/mL) selected according to known treatment schedules for human patients were incorporated into Sabouraud agar with chloramphenicol and Rose Bengal and diluted samples were inoculated onto the agar surface. After 7-d growth at 22°C colonies ofAlternaria sp.,Aspergillus clavatus. A. glaucus group,A. flavus. A, fumigatus, A. niger group,A. ochraceus group,A. ochraceus, Chœtomium sp.,Cladosporium cladosporioides. Cylindrocarpon sp.Doratomyces sp.,Fusarium sp.,F. moniliforme. F. oxysporum. F. solani, F. subglutinans. Marianaea elegans, Mortierella sp.,Mucor sp.,Myrothecium sp.,Penicillium sp.,Rhizopus sp.,Scopulariopsis brevicaulis. Sepedonium sp.,Stachybotrys chartarum. Stemphylium sp.,Torula humicola andTrichoderma viride were isolated.  相似文献   

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