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1.
Aims: To determine the stability and conidial yield of two strains of the entomopathogenic fungus Metarhizium anisopliae and one strain of M. brunneum, being developed for the control of insect pests. Methods and Results: The conidial yields and the shelf‐life of the conidia of two commercially viable strains of M. anisopliae V275 (=F52) and ARSEF 4556 and one strain of M. brunneum (ARSEF 3297) were determined after harvesting conidia from in vitro subcultures on Sabouraud dextrose agar (SDA) and broken basmati rice. The strains were stable and showed no decline in virulence against Tenebrio molitor, even when subcultured successively 12 times on SDA. Conidia‐bound Pr1 protease activity decreased in conidia harvested from SDA and mycosed cadavers after the 1st subculture, but increased in conidia produced on rice. The C:N ratio of conidia from mycosed cadavers was lower than that of conidia from rice or SDA. Irrespective of the number of subcultures, strain ARSEF 4556 produced significantly higher conidial yields than ARSEF 3297 and V275. The 12th subculture of V275 and ARSEF 3297 produced the lowest conidial yield. Shelf‐life studies showed that conidia of strain ARSEF 4556 had a higher conidial viability than V275 and ARSEF 3297 after 4 months, stored at 4°C. Conclusions: The current study shows that determining strain stability and conidial yield through successive subculturing is an essential component for selecting the best strain for commercial purposes. Significance and Impact of the Study: This is the first study to compare quality control parameters in the production of conidia on rice, and it shows that the level of Pr1 is comparatively high for inoculum produced on rice.  相似文献   

2.
The larvae of the pine processionary moth (PPM), Thaumetopoea pityocampa, feed on the needles of pine and cedar. The urticating hairs of older instars pose a threat to human and animal health. Strains of the entomopathogenic fungi, Metarhizium brunneum (V275, ARSEF 4556) and Beauveria bassiana (KTU-24), were assayed against first to fourth instar T. pityocampa using doses ranging from 1?×?105 to 1?×?108 conidia mL?1. The three strains differed slightly in their virulence but caused 100% mortality of all instars at the highest dose. The newly emerged or first instar larvae were extremely susceptible with 100% mortality being achieved 2–4 days post inoculation with V275 at all but the lowest dose. The fourth instar larvae appeared to be less susceptible than earlier instars. There was good horizontal transmission of conidia from treated to un-inoculated larvae. However, mortality was higher in third and fourth instars and where the ratio of inoculated versus untreated larvae was high. This we presume is due to spores being more readily trapped by the urticating hairs found on third and older instar larvae. Injection of the nests offers a simple and environmentally friendly way of controlling the pest with reduced risk to operators.  相似文献   

3.
The interspecific thermotolerance of several species of entomopathogenic fungi was evaluated based on the conidial water affinity. The species were divided between hydrophilic and hydrophobic conidia. The species with hydrophobic conidia were Beauveria bassiana (ARSEF 252), Metarhizium brunneum (ARSEF 1187), Metarhizium robertsii (ARSEF 2575), Isaria fumosorosea (ARSEF 3889) and Metarhizium anisopliae s.l. (ARSEF 5749). The species with hydrophilic conidia were Tolypocladium cylindrosporum (ARSEF 3392), Tolypocladium inflatum (ARSEF 4877), Simplicillium lanosoniveum (ARSEF 6430), Lecanicillium aphanocladii (ARSEF 6433), S. lanosoniveum (ARSEF 6651), Aschersonia placenta (ARSEF 7637) and Aschersonia aleyrodis (ARSEF 10276). The conidial surface tension of each isolate was also studied. Conidial suspensions were exposed to 38, 41 or 45 °C. After exposure, the suspensions were inoculated on media and conidial germination was evaluated. Considerable differences in thermotolerance were found among the 12 entomopathogenic fungal species. Species with hydrophobic conidia were generally more thermotolerant than species with hydrophilic conidia. All isolates with hydrophobic conidia showed higher conidial surface tension than the isolates with hydrophilic conidia.  相似文献   

4.
The large pine weevil, Hylobius abietis, is a major pest in European conifer forests causing millions of Euros of damage annually. Larvae develop in the stumps of recently felled trees; the emerging adults feed on the bark of seedlings and may kill them. This study investigated the susceptibility of different developmental stages of H. abietis to commercial and commercially viable isolates of entomopathogenic fungi, Metarhizium and Beauveria. All the developmental stages of H. abietis can be killed by Metarhizium robertsii, Metarhizium brunneum, and Beauveria bassiana. The most virulent isolate of M. robertsii ARSEF4556 caused 100% mortality of pupae, larvae and adults on day 4, 6 and 12, respectively. This strain was further tested against adult weevils in different concentrations (10(5)-10(8) conidia cm(-2) or ml(-1)) using two types of fungal formulation: 'dry' conidia and 'wet' conidia (suspended in 0.03% aq. Tween 80) applied on different substrates (tissue paper, peat and Sitka spruce seedlings). 'Dry' conidia were more effective than 'wet' conidia on tissue paper and on spruce or 'dry' conidia premixed in peat. The LC(50) value for 'dry' conidia of isolate ARSEF4556 was three folds lower than 'wet' conidia on tissue paper. This study showed that 'dry' conidia are more effective than 'wet' conidia, causing 100% adult mortality within 12days. Possible strategies for fungal applications are discussed in light of the high susceptibility of larvae and pupae to fungal pathogen.  相似文献   

5.
Bioassays were conducted to determine the susceptibility of egg masses and young larvae of two pine processionary moth species, Thaumetopoea pityocampa and Thaumetopoea wilkinsoni, to two strains (ARSEF4556, V275) of the entomopathogenic fungus Metarhizium brunneum. Mortality of treated eggs by both strains ranged from 96% to 99% but not all of this was caused by M. brunneum since control groups also experienced egg mortality due to saprophytic fungi. Still, larvae hatched in the laboratory from eggs treated with M. brunneum were all killed by this fungus, acquiring M. brunneum conidia, whereas larval mortality was 0% in the control groups. Young larvae of both pine processionary moth species were also highly susceptible to ARSEF4556 and V275 with larval mortality ranging between 94% and 100%, 8 days post-inoculation, with the vast majority of larvae being killed within the first 2–4 days. Larval mortality was dose dependent. Results were consistent across the two pine processionary moth species, showing that the pathogenicity of M. brunneum to both eggs and young larvae might be promising for biological control of these insect pests. The study also showed that non-target parasitoids of pine processionary moth eggs were also susceptible to M. brunneum. Further work is required to understand and reduce the M. brunneum effect on non-target insects.  相似文献   

6.
The eggs and second instar larvae of Spodoptera litura were treated with different concentrations of conidial suspensions of six isolates of fungi belonging to five species, Metarhizium anisopliae var. anisopliae (Metschnikov) Sorokin (ARSEF 7487), Lecanicillium muscarium (Petch) Zare & W Gams (ARSEF 7037 and ARSEF 6118), Cordyceps cardinalis (ARSEF 7193), Fusarium lateritium Nees (ARSEF 8291/MTCC 9050) and Aspergillus sp. (ARSEF 8519). In bioassay with unscaled eggs, M. anisopliae, C. cardinalis, F. lateritium and Aspergillus sp. resulted in 100% mortality above 106 conidia/mL. However, with scaled egg masses, the highest hatching rate (56%) was observed with L. muscarium (ARSEF 6118) whereas the lowest hatchings were observed in the case of M. anisopliae followed by L. muscarium (ARSEF 7037), Aspergillus sp., F. lateritium, and C. cardinalis. The larvae were also found susceptible to all isolates in a dose dependent manner. Three promising isolates against larvae, viz. M. anisopliae, F. lateritium and L. muscarium (ARSEF 7037) resulted in average percent mortalities of 88, 89 and 77%, respectively at ≈108 conidia/mL. When both larvae and the leaves (provided as food) were treated with ≈108 conidia/mL, mortality further increased for these isolates. Based on the mortality data and the LC50 values, we suggest that M. anisopliae, F. lateritium and L. muscarium (ARSEF 7037) could be developed as potential biocontrol agents against rice cutworm in IPM programs.  相似文献   

7.
An isolate from Argentina of the fungal mosquito pathogen Leptolegnia chapmanii (ARSEF 5499), was tested against 12 species of mosquito larvae and on species of non-target aquatic invertebrates and vertebrates. The mosquito species tested were Aedes aegypti, Anopheles sp., Culex apicinus, Cx. castroi, Cx. dolosus, Cx. pipiens, Cx. renatoi, Isostomyia paranensis, Ochlerotatus albifasciatus, Oc. crinifer, Psorophora cyanescens, and P. ferox. Mosquito larvae of 10 species were susceptible, with mortality rates from 10–100%. Two mosquito species Cx. renatoi and I. paranensis were not infected by Leptolegnia. None of the non-target fauna treated was infected by L. chapmanii with exception of members of the Family Chironomidae which were susceptible at low infection rates. Researcher CIC (Committee for Scientific Research of Buenos Aires State).  相似文献   

8.
Control of Anopheles albimanus, the main vector of malaria on the coast of the State of Chiapas, is based mainly on application of chemical insecticides, which has resulted in resistance to most registered insecticides. Strategies for biological control may provide sustainable alternatives. We report on the lethal effects of a native isolate of Gliocladium virens on An. albimanus larvae and adults, compared to that of strains of Beauveria bassiana and Metarhizium anisopliae. Conidial suspensions of G. virens, B. bassiana and M. anisopliae cultured on Sabouraud agar were tested in bioassays with An. albimanus larvae and adults. Mosquito larvae were more susceptible to all fungi, compared to adults. On early and late instar larvae, M. anisopliae showed the most pathogenic effect (LC50 of 1.4×105 conidia/mL in early instars; 1.1×105 conidia/mL in late instars), followed by G. virens (LC50 of 3.3×105 conidia/mL in early instars and 3.5×106 conidia/mL in late instars). Metarhizium anisopliae sensu lato and the native G. virens could be considered good choices for An. albimanus control in southern Mexico.  相似文献   

9.
Abstract.
  • 1 We assessed experimentally the effects of the predatory backswimmer, Notonecta maculata, on naturally colonizing mosquito populations in artificial outdoor pools in the Negev Desert, Israel. A single Notonecta adult per pool (8–15 litres water) had a very large negative impact on populations of Culiseta longiareolata, the most common species found in natural local pools. Notonecta caused large reductions of Culiseta egg rafts and early-instar larvae (instars I and II) and virtually 100% reductions of late-instar Culiseta larvae (instars III and IV) and pupae.
  • 2 Notonecta also caused a trophic cascade in the experimental pools; by preying on periphyton-feeding Culiseta larvae, Notonecta indirectly caused significantly higher densities of diatoms, the major component of the periphyton.
  • 3 Surveys of nearby natural pools taken between March and May supported the experimental results: a strong negative association between Notonecta and Culiseta among pools occurred as Notonecta increased in numbers and became more widely distributed. Anopheles (occurring only in May) and Culex mosquito immatures were not negatively associated with Notonecta. Culiseta was not associated with surface vegetation whereas both Culex and Anopheles showed strong positive associations with surface vegetation both among and within pools. We attribute the negative association between the predator and Culiseta to local prey extinctions caused by Notonecta in individual pools. Culiseta, being an open water species, is apparently more prone to predation by Notonecta than the vegetation-dwelling Culex and Anopheles.
  相似文献   

10.
The effects of different concentrations and methods of treatment with Metarhizium robertsii Bisch., Rehner & Humber conidia on the non‐target aquatic dragonfly larvae Lestes sponsa Hansemann, Lestes dryas Kirby and Aeshna affinis Vander Linden and on the target bloodsucking mosquito larvae Aedes (O.) flavescens (Muller) were analysed. We found that dragonflies are significantly less susceptible than mosquitoes to the fungus. Larvae of L. sponsa larvae were more susceptible to wet conidia than dry conidia. However, the mortality of the air‐breathing larvae of A. affinis was significantly higher after treatment with dry conidia relative to aqueous suspension. The results help to minimize the negative effects of entomopathogenic fungi on non‐target predator insects under the control of mosquito larvae.  相似文献   

11.
An updated checklist of the mosquito species (Diptera: Culicidae) recorded in Morocco from 1916 to 2016 is provided, including synonyms and synonymous usage for each species. Forty‐three species belonging to seven genera are recorded so far: Anopheles (9), Aedes (12) Coquillettidia (2), Culex (12), Culiseta (5), Orthopodomyia (1) and Uranotaenia (2). Traditional and equivalent names in the polyphyletic concept of Aedes are provided for the aedine species. The historical importance and current potential threat of mosquitoes to human health in Morocco is reviewed.  相似文献   

12.
The pupae of Spodoptera litura (Fab.), (Lepidoptera: Noctuidae), a polyphagous pest affecting common crops in Indian subcontinent, were treated with different concentrations of conidia of four isolates of entomopathogenic fungi belonging to three species, Metarhizium anisopliae var. anisopliae (Metschnikov) Sorokin (ARSEF 7487), Lecanicillium muscarium (Petch) Zare & W Gams (two isolates ARSEF 7037 and ARSEF 6118) and Cordyceps cardinalis Sung & Spatafora (ARSEF 7193) under laboratory conditions. Suspensions (108/ml) of conidia harvested from Sabouraud dextrose agar yeast extract (SDAY) plates resulted in the highest mortality (85.8%) with M. anisopliae and the lowest mortality (57.3%) with C. cardinalis. The values of LC50 and LC90 suggested that M. anisopliae was the most virulent fungal strain followed by L. muscarium (ARSEF 7037). However, C. cardinalis was the least virulent species among the fungi used in the bioassay. In soil bioassays, drenching the soil with conidial suspensions of ARSEF 7487 and ARSEF 7037 (10conidia/g of soil) reduced the adult emergence from pupa by 81.3% and 72.5%, respectively, while premixing the sterile soil with conidia killed lesser number of pupae (62.9% by ARSEF 7487 and 54.6% by ARSEF 7037). Our findings suggest that M. anisopliae (ARSEF 7487) and L. muscarium (ARSEF 7037) are potent entomopathogens and could be developed into biocontrol agents against rice cutworm in IPM programs. Handling editor: Helen Roy  相似文献   

13.
The cyclopoid copepod Mesocyclops thermocyclopoides, a dominant invertebrate predator in many shallow ponds and temporary water bodies in northern India, feeds on cladocerans, rotifers, ciliates and when present, on mosquito larvae also. We studied in the laboratory the prey consumption rates of the copepod on first and fourth instar larvae of two species of mosquito (Anopheles stephensi and Culex quinquefasciatus) in relation to their density. We also studied its prey selectivity with mosquito larvae in the presence of an alternate prey (the cladocerans‐either Moina macrocopa or Ceriodaphnia cornuta) in different proportions. With either mosquito species, the copepod actively selected Instar‐I larvae, avoiding the Instar‐IV larvae, and with either instar, selected Anopheles stephensi over Culex quinquefasciatus. When prey choice included the cladoceran as an alternate prey, the copepod selected the cladoceran only when the other prey was Instar‐IV mosquito larvae. Our results point to the potential and promise of M. thermocyclopoides as a biological agent for controlling larval populations of vectorially important mosquito species.  相似文献   

14.
In order to improve the limited database on species inventories and ecology of Culicidae in Austria, we monitored hydrological and physico-chemical parameters of breeding habitats of the Culicidae species of Danubean wetlands from March to October 2011 in the National Park Donau-Auen (Lower Austria). A total of 34 eggrafts, 1022 larval, 80 pupal, and 221 adult Culicidae were collected. We detected 15 mosquito species belonging to the genera Anopheles Meigen, 1818, Culex Linnæus, 1758, Culiseta Felt, 1904, Coquillettidia Dyar, 1905, Aedes Meigen, 1818 and Ochlerotatus Lynch Arribalzaga, 1891. In the larval and pupal stage, Ochlerotatus geniculatus (Olivier, 1791) (64.1%) and Culex territans Walker, 1856 (18.7%) were most abundant. Based on abiotic and biotic parameters, sampling sites were grouped into four clusters. The results show that water level and -persistence, pH, conductivity, and phosphate concentrations had a significant influence on species distribution, and that floodplain dynamics are a key factor for the seasonal and spatial distribution of mosquito larvae in the National Park.  相似文献   

15.
Mosquitoes are important vectors that transmit pathogens to human and other vertebrates. Each mosquito species has specific ecological requirements and bionomic traits that impact human exposure to mosquito bites, and hence disease transmission and vector control. A study of human biting mosquitoes and their bionomic characteristics was conducted in West Sumba and Southwest Sumba Districts, Nusa Tenggara Timur Province, Indonesia from May 2015 to April 2018. Biweekly human landing catches (HLC) of night biting mosquitoes both indoors and outdoors caught a total of 73,507 mosquito specimens (59.7% non-Anopheles, 40.3% Anopheles). A minimum of 22 Culicinae species belonging to four genera (Aedes, Armigeres, Culex, Mansonia), and 13 Anophelinae species were identified. Culex quinquefasciatus was the dominant Culicinae species, Anopheles aconitus was the principal Anopheles species inland, while An. sundaicus was dominant closer to the coast. The overall human biting rate (HBR) was 10.548 bites per person per night (bpn) indoors and 10.551 bpn outdoors. Mosquitoes biting rates were slightly higher indoors for all genera with the exception of Anopheles, where biting rates were slightly higher outdoors. Diurnal and crepuscular Aedes and Armigeres demonstrated declining biting rates throughout the night while Culex and Anopheles biting rates peaked before midnight and then declined. Both anopheline and non-anopheline populations did not have a significant association with temperature (p = 0.3 and 0.88 respectively), or rainfall (p = 0.13 and 0.57 respectively). The point distribution of HBR and seasonal variables did not have a linear correlation. Data demonstrated similar mosquito–human interactions occurring outdoors and indoors and during early parts of the night implying both indoor and outdoor disease transmission potential in the area–pointing to the need for interventions in both spaces. Integrated vector analysis frameworks may enable better surveillance, monitoring and evaluation strategies for multiple diseases.  相似文献   

16.
Most information about the systematics and bioecology of Belgian mosquitoes dates back from before 1950, and only scattered information was produced during the last decades. In this paper we review and update the list of mosquito species recorded in Belgium, from first report (1908) to 2015. Six genera and 31 species were recorded so far, including 28 autochthonous species and three invasive alien species recently recorded in Belgium: Aedes albopictus (Skuse 1894), Ae. japonicus japonicus (Theobald 1901), and Ae. koreicus (Edwards 1917). The six genera are Anopheles (five species), Aedes (sixteen species), Coquillettidia (one species), Culex (four species), Culiseta (four species), and Orthopodomyia (one species).  相似文献   

17.
Abundances of mosquito larvae and associated invertebrate communities were assessed in 27 temporary ponds during the spring season in wetland areas of Germany. Four genera of mosquitoes were identified: Aedes, Anopheles, Culex, and Culiseta. We focused our analyses on Aedes spp. because this genus was the most abundant (92% of total abundance) and frequently encountered mosquito (present in 65% of investigated sites). The abundance of Aedes spp. was negatively associated with the abundance of competitors for food, and to a lesser extent with those of intraguild predators and strict predators. The influence of these natural antagonists on larvae of Aedes was stronger in ponds with higher levels of dissolved oxygen (53 ± 4%) than in ponds with lower levels (16 ± 1%). The overall abundance of antagonists explained 42% of the variation in abundance of Aedes spp. at sites with higher levels of dissolved oxygen. Of this explained variation, competitors accounted for 34.7%, whereas the abundance of intraguild predators and strict predators accounted for only 6.8 and 0.5%, respectively. Therefore, the promotion of competing species might be an appropriate ecological approach for the control of Aedes spp. in temporary ponds in these areas.  相似文献   

18.
Previous studies which have tested the feeding preferences of shredders for fungal species and the food quality of fungi used detritus uniformly colonized by a fungus, which is not the case for decaying leaves in streams. It is not known whether shredders in different development stages exhibit variations in feeding preference and larval performance. This study examined the feeding preferences and the growth of the third and the fifth instars of Pycnopsyche gentilis larvae using fungal-colonized patches and whole leaves, respectively, having different fungal species compositions (Alatospora acuminata, Anguillospora filiformis, Articulospora tetracladia, Tetrachaetum elegans, and all species combined). The aquatic hyphomycetes used were co-dominant on leaves in the stream inhabited by the caddisfly. During 14 d of feeding, the larvae of both instars did not show significant differences in feeding preferences for the patches growing on oak leaves, although the third instar larvae were slightly more selective than the fifth instar larvae. When fed with maple leaves for 18 d, larval growth rates, gross growth efficiencies, and survivorship were not significantly different among the fungal treatments. However, the larval growth of both instars fed with fungal-colonized leaves was always significantly greater than the growth of larvae fed with diets of uncolonized leaves. The third instar larvae grew faster than the fifth instar larvae, but the growth efficiencies of the two instars were similar. These results suggest that P. gentilis larvae exhibit less selectivity in their feeding than other caddisfly shredders that have been examined and that the dominant fungi colonizing leaves in their habitat are similar in palatability and food quality for this shredder. Handling editor: B. Oertli  相似文献   

19.
Frequency dependent mosquito larval size (II and IV instars) and species selection by the water bug Diplonychus indicus against three mosquito species Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi was studied in the laboratory. The different frequencies used for each species selection were 20:30:50, 30:50:20, 50:20:30, 25:35:40, 35:40:25 and 40:25:35 of fourth instars of the respective three prey species. All nymphal water bugs (I–V instars) selected IV instar mosquito larvae and the mean proportion of late (larger) larvae eaten by the predator instars was significantly higher than the mean proportion of early (smaller) larvae eaten (F= 2.28; P < 0.001). In all six ratios used to determine the frequency dependent mosquito species selection, all the stages of the water bug selected Ae. aegypti over the other two species (F= 452.43; P < 0.001). The mean number of mosquito larvae eaten increased as its density increased based on various ratios of larvae offered. The study indicated that the predatory efficiency of D. indicus was high when Ae. aegypti was offered as prey, suggesting the utility of this mosquito predator in the control of dengue vectors.  相似文献   

20.
Improvement of morphological and molecular identification methods allows the detection of new species of mosquitoes. The mosquito fauna of Croatia currently includes 52 species, belonging to eight genera, including Anopheles (12 species), Aedes (24 species), Coquillettidia (one species), Culex (seven species), Culiseta (six species), Orthopodomyia (one species), and Uranotaenia (one species). This is an updated checklist, which includes five new species found in Croatian mosquito fauna. Two of these are invasive mosquito species, Aedes albopictus (Skuse, 1895) and Aedes japonicus (Theobald 1901), which are spreading across Europe and Croatia. The other three species, Culex laticinctus (Edwards 1913), Culex torrentium (Martini 1925), and Anopheles daciae (Linton, Nicolescu & Harbach 2004) are autochthonous species which haven't been recorded so far. Since there are several more invasive species spreading across Europe, we assume that this is not the final list.  相似文献   

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