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1.
Spodoptera litura Fab. (Lepidoptera, Noctuidae) is a polyphagous pest and has been shown to be resistant to a wide range of insecticides, which has led to sporadic out breaks of the pest and failure of crops. We were interested to establish if resistance to insecticides is diverse in different populations of S. litura collected from various areas with variable temperatures. We collected S. litura from eight different locations and compare the toxicity of insecticides. Resistance to the pyrethroids ranged from 20- to 11,700-fold compared with the Lab-PK (laboratory susceptible population). The resistance to bifenthrin was the lowest in a population collected from Multan and the highest to esfenvalerate in a population collected from Lodhran. Similarly, very high level of resistance to spinosad, indoxacarb, and methoxyfenozide was observed in all eight populations. In contrast, resistance to organophosphates was significantly lower than the pyrethroids, spinosad, indoxacarb, and methoxyfenozide, while toxicity of emamectin to field populations was similar to the Lab-Pk. The results are discussed in relation to integrated pest management (IPM) for S. litura with special reference to management of field evolved resistance to insecticides.  相似文献   

2.
The efficiency of the botanical insecticide (BI) NeemAzal T/S (containing 1% Azadirachtin A), on the basis of azadirachtin applied in a dose of 20 g a.i. ha−1 against Brassica pod midge (Dasineura brassicae), has been monitored for 4 years. The biological efficiency of BI was compared with the efficiency of some synthetic insecticides. It was ascertained that BI was very efficient in decreasing the number of damaged oilseed rape pods (ranging from 56.5 to 85.9% compared to untreated plants) and its efficiency was comparable with synthetic insecticides based on Chloronicotinyl (Thiacloprid) and Neonicotinoid (Acetamiprid). BI’s efficiency was, in some years, even significantly higher compared to pyrethroid (λ-cyhalothrin). The high biological efficiency of azadirachtin that we ascertained was significantly reflected in increasing potential crop yields. The yield increase of azadirachtin ranged between 9.3 and 19.4% compared to the control sample. Azadirachtin showed the highest yield for the whole time of experimentation, and in some years the yield increase was significantly higher compared to some synthetic agents.  相似文献   

3.
Macrolophus pygmaeus is a polyphagous mirid bug native to the Mediterranean area where it is widely used in the biological control of whiteflies and other pests in vegetable crops. To assess the presence of eggs in females is important in order to optimize predator release strategies, as well as their mass rearing. This study shows an alternative to the traditional procedures of fertility assessment based on evaluation of newly hatched nymphs. A polyclonal antiserum was produced against M. pygmaeus egg proteins, and an ELISA protocol was developed to determine whether laboratory-reared or field-collected females contained egg proteins (mainly vitellin). When field-collected females were analysed, an 80% contained egg proteins indicating that they were reproductively active. Presence/absence of egg proteins was detected with an error than 1%. Since this ELISA protocol allowed also the detection of egg protein precursors, it was more precise and less time consuming than conventional techniques as abdomen dissection or egg-hatch evaluation in determining egg presence in females.  相似文献   

4.
Shoot and fruit borer, Leucinodes orbonalis Guenee, is a serious pest of eggplant (Solanum melongena L.). Management practices of this obnoxious pest are limited to frequent spray of chemical insecticides. Due to increasing levels of resistance of L. orbonalis to different insecticides there is an urgent need to test new chemicals. In this study, nine insecticides such as azadirachtin 0.03EC, abamectin 1.8EC, flubendiamide 24WG, chlorpyriphos 20EC, cartap 50SP, carbosulfan 20EC, thiodicarb 75WP, cypermethrin 10EC, and lambdacyhalothrin 2.5EC belonging to different chemical groups were tested against eggplant shoot and fruit borer in laboratory and field. In laboratory trial, carbosulfan and flubendiamide showed the highest toxicity against fourth instar larvae of L. orbonalis after 24 and 48 h of exposure, respectively. In field trials, they reduced more than 80% shoot and fruit infestation in winter, and 80% shoot and 70% fruit infestation in summer over control. Carbosulfan protected the highest amount of healthy fruit yield in both cropping seasons. Flubendiamide also showed the similar efficacy. Cartap and thiodicarb were moderately effective in both the seasons. Efficacy of cypermethrin and abamectin was moderate in winter but low in summer. Lambdacyhalothrin and chlorpyriphos although reduced shoot and fruit infestation of eggplant and protected higher yield as compared to control, their effectiveness was not satisfactory. The performance of azadirachtin against the pest both in the laboratory and field trials was the poorest while that of carbosulfan and flubendiamide was the best. Thus, it is suggested that carbosulfan and flubendiamide may be used for the control of L. orbonalis in eggplant.  相似文献   

5.
Trichogramma chilonis Ishii is an important natural enemy of several lepidopterous pests on crops. The effects of two common insecticides on sex pheromone communication and mating behavior in T. chilonis were evaluated in the laboratory. When only males were exposed to insecticide, beta-cypermethrin LC20 exposure induced significant decrease in sex pheromone perception by males and significant increase in males’ courtship and copulation frequency; beta-cypermethrin LC1 exposure caused significant decrease in males’ courtship and copulation frequency. Males exposed to spinosad LC20 exhibited significantly slower initiated courtship and significantly shorter total copulation duration, and the males exposed to spinosad LC1 exhibited significantly increased sex pheromone perception, compared with control. When both males and females were exposed to insecticide, significantly more courtship and copulation were conducted by treated pairs that survived insecticide (beta-cypermethrin or spinosad) LC20 than control pairs. Our study suggests that even the LC1 and LC20 of tested insecticides could affect the sex pheromone communication and mating behavior in T. chilonis.  相似文献   

6.
Despite continuous use of synthetic insecticides during last two decades, the tea mosquito bug, Helopeltis theivora Waterhouse (Miridae: Heteroptera), has become the most destructive sucking pest of tea in North East India. In order to reduce the load of the synthetic chemicals in tea vis-à-vis their deleterious effect, integration of biopesticide, synthetic pesticides along with effective spraying strategies, have been attempted. The anti-insect property of “neem”, Azadirachta indica A. Juss. (Meliaceae), has been used to solve many pest problems. In this study, different azadirachtin concentrations were evaluated at different doses against the H. theivora to find out their controlling efficacy. At 50,000 ppm azadirachtin concentration 65% control of infestation could be attained, whereas at 3,000 and 10,000 ppm, gave 30–43% reduction and 300 and 1,500 ppm <30% control was possible. Further in case of 3,000 and 10,000 ppm, azadirachtin concentration 30–43% reduction was registered. Therefore, azadirachtin concentration and its dilutions are the major criteria for getting desired bioactivity. Treatments with combined formulations viz. “neem + endosulfan” or “neem + deltamethrin” recorded significant reduction in H. theivora incidence even at reduced doses, as compared to sole application of neem or synthetic insecticide at recommended doses. Effective combinations and dose of the insecticides along with their formulations in controlling H. theivora have been presented and discussed.  相似文献   

7.
The alfalfa leafcutting bee, Megachile rotundata (Fabricius), is a valuable wild and managed pollinator of lowbush blueberry (syn. ‘wild blueberry’, Vaccinium angustifolium Ait.), in Atlantic Canada. As some insecticides may present a hazard to pollinators, we assessed the susceptibility of M. rotundata to insecticides used or projected for future use in lowbush blueberry pest management. In topical direct contact bioassays, adults were susceptible to phosmet, spinosad, spinetoram, and deltamethrin. Based on findings from these laboratory studies, it appears that when used at recommended or projected application rates, each of these compounds poses a hazard to M. rotundata by direct contact. In a second experiment, eggs and larvae were collected in the field and their pollen provisions were treated with deltamethrin, flubendiamide, and spinetoram at field relevant concentrations. Larvae treated with deltamethrin and spinetoram in the laboratory either died before spinning a cocoon or, in the case of spinetoram, occasionally pupated without spinning a cocoon. Flubendiamide was not toxic to adult M. rotundata by direct contact and had no effect on larval survivorship, or time to complete cocoon spinning. Emergence after overwintering was relatively poor overall, but there was no effect of treatment. Based on these results, flubendiamide appears safe to use in the presence of M. rotundata, whereas the other insecticides we tested may pose a hazard.  相似文献   

8.
Poplar leaf defoliator, Clostera fulgurita (Walker) larvae were reared on three Populus deltoides clones (PL1, PL5 and PL7) in the laboratory. The nutritional indices were computed for working out the relationship between food consumption and growth rate of 3rd, 4th and 5th instar larvae on three clones. The result showed that the consumption index (CI), approximate digestibility (AD), growth rate (GR), relative growth rate (RGR) and efficiency of conversion of ingested food (ECI) decreased with the increase in the age of the larvae. Efficiency of conversion of digested food (ECD) increased with increase in age of the larvae. GR and RGR varied significantly, indicating that larval development was enhanced on PL1 as compared to PL5 & PL7. The values of AD, ECI and ECD were not affected by the different clones. Feeding and growth indices could be useful to define a defoliation prediction model.  相似文献   

9.
The European corn borer (ECB), Ostrinia nubilalis (H?bner) (Lepidoptera: Crambidae), is the major arthropod pest of corn in Croatia. However, chemical control is carried out only in maize for seed production, and in sweet corn. A 3-year investigation was carried out in corn fields in northwest Croatia to establish the most attractive pheromone lure for ECB monitoring, the optimal timing of insecticide applications, and the efficacy of selected insecticides against ECB. During each of the 3 years, the pheromone lures E, Z and E/Z («Isagro») were evaluated in the field from May to July. Insecticides were sprayed 14–20 days after the maximal capture in 2002 and 2003. In 2004, three different trials were set up: one trial with one early treatment (when corn was in the R49 development stage according to the extended BBCH scale); one with one late treatment (when corn was in the R65 development stage according to the BBCH scale); and one with two treatments in both stages. In the trials studying Bacillus thuringiensis var. kurstaki (B.t.k.), insect growth regulators (IGR), spinosad and classical chemical insecticides were applied. Pheromone lure E was the most attractive for monitoring ECB flights throughout 2 years of investigation. Insecticide efficacy depended on application timing. The insecticides most suitable for integrated pest management (IPM) programs, including spinosad, B.t.k. and IGR, resulted in high (spinosad) to moderate (B.t.k.) efficacy. The efficacy of IGRs indicates the need for earlier application. The efficacy of chemical insecticides depended on the year and the insecticide. The organophosphate (OP) insecticides and pyrethroids gave moderate to good results; imidacloprid did not provide significant efficacy. One application of all insecticides based on proper (early) timing resulted in the same efficacy as two applications of the same insecticides.  相似文献   

10.
Several species of the large family of tropical plants Annonaceae have been intensely investigated over the last 20 years, mainly because of the discovery of annonaceous acetogenins. These compounds are powerful cytotoxics, with potential applications as insecticides, antiparasitics, acaricides, fungicides, and antitumor drugs. Annona montana Macfad. (Annonaceae) grows in Santa Cruz de la Sierra, Bolivia, where an infusion of leaves is used for the treatment of lice, influenza, and insomnia. The major acetogenins from a Bolivian collection of A. montana, annonacin (1), cis-annonacin-10-one (2), densicomacin-1 (3), gigantetronenin (4), murihexocin-B (5), and tucupentol (6), were evaluated for their antifeedant and toxic effects on Spodoptera frugiperda Smith (Lepidoptera: Noctuidae), a serious pest affecting corn crops in Argentina. All the acetogenins produced 100% mortality during the larval or pupal stages at 100 μg of treatment per gram of diet. In addition, compounds 2, 3, and 4 deterred more than 80% feeding at the same dose. Relative toxicity values of LD50 for the strongest larvicidal compounds 1, 2, and 4 were determined, indicating that the three compounds are effective natural insecticides. This is the first report on the antifeedant and toxic effects produced by the particular type of acetogenins, the mono-THF acetogenins, on the lepidopteran S. frugiperda. No correlation was detected between the toxicity of the mentioned compounds to larvae and the known capacity of the acetogenins 1, 2, and 4 to inhibit the NADH oxidase, indicating that the inhibition of the mitochondrial complex I is not the only cause for larval mortality of S. frugiperda.  相似文献   

11.
The side effects of methoxyfenozide, indoxacarb, pyridaben, acetamiprid, azadirachtin A, spinosad, and propargite on Aphidius colemani, Aphidoletes aphidimyza, and Neoseiulus cucumeris were tested under laboratory conditions. Methoxyfenozide had low toxic effect on all three species, causing mortality after 24 h in 4.4, 11.4, and 29.3% of N. cucumeris, A. colemani, and A. aphidimyza, respectively. Similarly, indoxacarb caused mortality after 24 h in 11.9, 20.0, and 24.9% of A. aphidimyza, N. cucumeris, and A. colemani, respectively. In general, N. cucumeris exhibited the lowest sensitivity to all the insecticides. In contrast, A. colemani was highly sensitive to most of the tested insecticides. Methoxyfenozide was shown to significantly reduce fecundity of A. aphidimyza. In contrast, there was no effect of pure azadirachtin A on A. colemani fecundity. Results showed that both methoxyfenozide and indoxacarb would be suitable for use in the integrated pest management (IPM) because of their low toxic effect against all of the tested model species of natural enemies.  相似文献   

12.
Toxicity by contact and by ingestion of lufenuron, flufenoxuron, lambda (λ)-cyhalothrin, cypermethrin, thiamethoxam and five entomopathogenic insecticides (three formulations of Beauveria bassiana, a compound containing spores of Metarhizium anisopliae var. acridum, and a mixture of Brevibacillus laterosporus, Bacillus licheniformis and Bacillus chitinosporus) were evaluated on adults of the Eucalyptus snout-beetle Gonipterus scutellatus Gyllenhal (Coleoptera: Curculionidae) under laboratory conditions. By contact, entomopathogenic fungus B. bassiana EC and the pyrethroid λ-cyhalothrin exhibited the highest efficiency, achieving 100 and 97.5% mortality, respectively. By ingestion, the highest mortality was obtained by B. bassiana EC (100%) and thiamethoxam (95%). Flufenoxuron and lufenuron, bacteria mixture and M. anisopliae showed a weak toxicity. Furthermore, we found a sex-biased mortality, being males more affected. Due to the good performance and low risk to humans and environment, B. bassiana EC (strain PPRI 5339) appears to be the most promising product to promote an IPM programme in South Africa.  相似文献   

13.
The invasive brown marmorated stink bug Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) has become a serious economic pest in parts of the USA, and control tactics are often needed in order to avoid crop losses in tree fruit and other crops. Chemical control is usually the most effective and efficient tactic for preventing damage in crops. Researchers have tested a wide range of insecticides using laboratory and field experiments to determine the best options for H. halys control in the USA. This review summarizes that work and describes current practices with regard to insecticide options for H. halys.  相似文献   

14.
Trichogramma spp. are major parasitoids of lepidopteran pest eggs, but there is large variation in efficacy toward a given pest among the numerous described Trichogramma species. It is important to select the Trichogramma species that most effectively parasitize and develop in target pest eggs for biological control. In this context, Trichogramma pretiosum, T. exiguum, T. atopovirilia and T. acacioi were studied in Heliothis virescens eggs under different thermal conditions. The parasitoids were reared at constant temperatures of 20, 25 and 30°C and tested at these respective temperatures, while parasitoids reared at 25°C were also tested at 20 and 30°C, for a total of 20 species–temperature combinations. About 30 H. virescens eggs were offered to the parasitoids for 24 h. Among the four species, parasitism rate by T. atopovirilia was highest at all temperature conditions, whereas T. acacioi had the lowest rates of parasitism at 25°C and 25/30°C. Parasitism ranged from 13.8 to 43.8% among all species–temperature combinations. Viability (emerged parasitoids) ranged from 80.8 to 98.4%, and was deemed satisfactory. The emergence rates of T. exiguum and T. acacioi were affected by temperature. Temperature also affected the sex ratio of T. exiguum at 25/30°C, whereas T. pretiosum and T. acacioi produced females predominantly independent of temperature. Overall, the parasitoid T. atopovirilia was the most efficient in parasitizing H. virescens eggs, though the levels of parasitism obtained might not ensure its successful use in biological control programs. The temperature-related differences in biological traits observed in the four Trichogramma species tested hint at the importance of making careful choices regarding climatic conditions where the parasitoid is going to be used when selecting a species for biological control programs.  相似文献   

15.
Field experiments were carried out to ascertain whether synthetic floral odour compounds were attractive for two pest bug species. The European tarnished plant bug (Lygus rugulipennis Poppius) has been reported to damage various crops (e.g. strawberry, sugarbeet, alfalfa, cucumber), and the alfalfa plant bug (Adelphocoris lineolatus (Goeze)) is considered as a pest of alfalfa and Bt-cotton. In our field tests, traps baited with phenylacetaldehyde caught significantly more L. rugulipennis than unbaited traps. In addition, A. lineolatus was also attracted to phenylacetaldehyde-baited traps. When testing other, EAG active compounds, (E)-cinnamaldehyde attracted A. lineolatus as well. This compound was also attractive for L. rugulipennis, however, to a lesser extent than phenylacetaldehyde. When the two compounds were presented in combination, no synergistic or inhibitory effect was detected in either species. By attracting both sexes of both species, these new attractants may prove to be useful and provide the basis for further development of new lures for agricultural use.  相似文献   

16.
Bursaphelenchus mucronatus Mamiya et Enda has been recovered for the first time from adults of the cerambycid beetle, Monochamus urussovi (Fischer), in Hokkaido, Japan. The nematode was also recovered from the inner bark of Picea jezoensis (Siebold et Zuccarini) Carrière and Abies sachalinensis (Fr Schmidt) Masters infested with M. urussovi larvae. PCR–RFLP analysis indicated that B. mucronatus in Hokkaido is the European type.  相似文献   

17.
The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is the most important pest of cultivated Brassica worldwide, including those grown in greenhouses like cauliflower. In this article, we evaluate the potential of various species (and various strains of some species) of Trichogrammatidae (Hymenoptera: Chalcidoidea) to control this pest on cauliflower in greenhouse in France. We assessed the parasitism levels on P. xylostella of 17 Trichogrammatidae strains, belonging to 12 different species (2 indigenous strains from France), under greenhouse conditions. Parasitism levels for each of the Trichogrammatidae species and strains were determined on cauliflower leaves (Brassica oleracea botrytis L., Brassicaceae) infested with P. xylostella eggs. Nine strains parasitized 60% (or more) of the P. xylostella eggs. Compared to previous results in laboratory conditions, climatic conditions of the greenhouse did not influence parasitism levels. The presence of the cauliflower plants may have a positive effect on eight strains, a negative effect on four strains and no effect on five strains. Our study points out the importance of including the host plant of P. xylostella when conducting studies aiming to select the most efficient parasitoid against this pest.  相似文献   

18.
In this study, we examined the role of interspecific competition between native species and Mus musculus by a removal experiment conducted in vacant areas of the city of Río Cuarto. Abundance, demographic parameters, and habitat occupancy of M. musculus were recorded in grids where native species were removed (experimental grids) and in grids without removal (control grids) from November 2004 to April 2005. During the study period, we observed an increasing trend in the abundance and habitat occupancy by M. musculus in experimental grids, suggesting that interspecific competition could be determining the numbers and habitat use of M. musculus in vacant areas of the city of Río Cuarto. Understanding the population ecology of M. musculus in an urban area is crucial to the development of ecologically based pest management to provide effective management of a pest species.  相似文献   

19.
The whitefly Bemisia tabaci is a serious pest of eggplants, especially those grown undercover in polytunnels and greenhouses. Due to increasing levels of resistance of B. tabaci to a wide range of insecticides, there is now an urgent need to explore other non-chemical methods of control. In this study, Serangium parcesetosum, a ladybird, was evaluated as a possible biological control agent of B. tabaci’s winter and spring populations which infests eggplants grown undercover in Turkey. It was found that in winter, S. parcesetosum failed to control B. tabaci, even when the ladybird population was augmented six times over the course of the experiment. This contrasted with that observed in spring when, with only one introduction of the ladybird, control of the pest was gained within 3 weeks after release. In spring, the B. tabaci population in the cages receiving two and four S. parcesetosum adult per plant showed 56 and 53% reduction, respectively. The percent reduction in B. tabaci population rose to 98.6 and 98.3% in both cages, respectively, by the end of experiment. It is suggested that release of S. parcesetosum against B. tabaci during spring months may be offered as an alternative solution to increase implementation of biologically based B. tabaci management. In winter other biological control agents are needed and these need to be further explored.  相似文献   

20.
Citrus mealybug Planococcus citri (Risso) (Hemiptera: Pseudococcidae) is one of the main pests on citrus trees. Biological control of the pest is based on the release of hymenopterous parasitoids and coccinellid predators at present. The effectiveness of entomopathogen fungus Isaria farinosa (Holmsk.) Fries ([Sordariomycetes: Hypocreales] (Syn: Paecilomyces farinosus), as an alternative biological control agent on citrus mealybug, was investigated using four different inoculum densities and different relative humidities (RH). The entomopathogen caused 89.39% mortality in ovisacs, 84.07% mortality in second larval stage, 84.53% mortality in adult females, and 78.71% mortality in first larval stage at 95% RH and at 1 × 108 conidia ml−1 inoculum concentration. Percent mortalities were between 50 and 60 in ovisac, first and second larval stage at 95% RH and at 1 × 107 conidia ml−1. Percent mortality was decreased parallel to the decrease in humidity level and inoculum densities; however, the fungus caused significant infection in 70% and 80% RH. These results demonstrated that the effectiveness of the entomopathogen is promising for biocontrol of citrus mealybug.  相似文献   

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