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1.
The potential for using the entomopathogenic fungus Lecanicillium muscarium to control the sweetpotato whitefly, Bemisia tabaci has been well established in previous studies under both laboratory and glasshouse conditions. In the current study, five chemicals were assessed for their compatibility with L. muscarium for control of B. tabaci under glasshouse conditions. On treatments following the sequential application of chemical product and fungus high mortality of second instar larvae was obtained (the known most susceptible B. tabaci life-stage to fungal infection). Sequential treatment of Savona and Certis spraying oil with L. muscarium produced 95 % and 96 % larval mortality, respectively. Commercially, unacceptable poinsettia foliage damage was recorded seven days post application of Agri-50E. Other plant foliage may prove more tolerant to this product. Incorporation of these chemicals with L. muscarium into integrated control programmes for B. tabaci control in glasshouses is discussed. Further information has been added to the knowledge base for the combined use of chemicals and fungi for the control of B. tabaci.  相似文献   

2.
The majority of recent quarantine schedules have relied on methyl bromide fumigation. However, due to the phase-out of this fumigant in January 2005 alternative treatments are needed. Four alternative chemical fumigants were tested for their potential to replace methyl bromide as a control agent for Bemisia tabaci, Liriomyza huidobrensis and Frankliniella occidentalis. Phosphine at 2 g/m3 gave promising results at 15 °C with complete mortality of all insects after 24 h exposure. Sulphuryl fluoride, ethyl formate and acetaldehyde caused severe damage to plant foliage after only 4 h exposure. However, sulphuryl fluoride produced 100 % mortality of L. huidobrensis pupae after only 2 h exposure. In a large scale test using phosphine 2 g/m3 at 15 °C complete mortality of L. huidobrensis eggs and pupae was recorded after a 24 h exposure. However, only 98.5 and 86 % mortality of B. tabaci eggs and F. occidentalis eggs, respectively, was recorded after this treatment. Treatments with phosphine produced no significant detrimental effects on subsequent plant growth. The potential of these chemicals to act as alternatives to methyl bromide as quarantine fumigants is discussed.  相似文献   

3.
Waste engine oil causes a vital environmental pollution when it spill during change and transportation and products of waste engine oil causes lethal effects to the living systems. Thus, abiotic and biotic approaches are being extensively used for removal of waste engine oil pollution. Therefore in present study, waste engine oil degradation was accomplished by a new bacterial culture, isolated from the soil by an enrichment technique. Morphological, biochemical and gene sequence analysis revealed that isolate was Bacillus cereus. Subsequently, biodegradation potential of B. cereus for waste engine oil was studied. Experimental variables, such as pH, substrate concentration, inoculum size, temperature and time on the biodegradation, were checked in mineral salt medium. The biodegradation efficiency of B. cereus was determined by gravimetry, UV–visible spectrophotometry and gas chromatography. In addition, waste engine oil was also characterized by GC–MS and FTIR for its major constituents, which showed total 38 components in waste engine oil, including hopanes, benzopyrene, long-chain aliphatic hydrocarbons, dibenzothiophenes, biphenyl and their derivatives. Results of successive biodegradation indicated that B. cereus was capable to degrade 1% of waste engine oil with 98.6% degradation potential at pH 7 within 20 days. Hence, B. cereus presents an innovative tool for removing the engine oil from the contaminated area.  相似文献   

4.
Bioremediation is an effective measure in dealing with such contamination, particularly those from petroleum hydrocarbon sources. The effect of soil amendments on diesel fuel degradation in soil was studied. Diesel fuel was introduced into the soil at the concentration of 5 % (w/w) and mixed with three different organic wastes tea leaf, soy cake, and potato skin, for a period of 3 months. Within 84 days, 35 % oil loss was recorded in the unamended polluted soil while 88, 81 and 75 % oil loss were recorded in the soil amended with soy cake, potato skin and tea leaf, respectively. Diesel fuel utilizing bacteria counts were significantly high in all organic wastes amended treatments, ranging from 111 × 106 to 152 × 106 colony forming unit/gram of soil, as compared to the unamended control soil which gave 31 × 106 CFU/g. The diesel fuel utilizing bacteria isolated from the oil-contaminated soil belongs to Bacillus licheniformis, Ochrobactrum tritici and Staphylococcus sp. Oil-polluted soil amended with soy cake recorded the highest oil biodegradation with a net loss of 53 %, as compared to the other treatments. Dehydrogenase enzyme activity, which was assessed by 2,3,5-triphenyltetrazolium chloride technique, correlated significantly with the total petroleum hydrocarbons degradation and accumulation of CO2. First-order kinetic model revealed that soy cake was the best of the three organic wastes used, with biodegradation rate constant of 0.148 day?1 and half life of 4.68 days. The results showed there is potential for soy cake, potato skin and tea leaf to enhance biodegradation of diesel in oil-contaminated soil.  相似文献   

5.
Seasonality and abundance of ichthyoplankton in great South Bay,New York   总被引：1，自引：0，他引：1  
The seasonality and abundance patterns of ichthyoplankton were investigated during 1985–1986 in Great South Bay, New York, USA. Eggs representing 17 species and larvae representing 23 species of fish were identified. Bay anchovy, Anchoa mitchilli, was the most abundant ichthyoplankter, comprising >96% of the eggs and >69% of the larvae collected. Bay anchovy spawned throughout the bay from late May through August, with peak baywide densities of >200 eggs and 6 larvae m?3. Eggs of windowpane flounder (Scophthalmus aquosus) ranked second in abundance and were present in both spring and fall. Other dominant larvae were winter flounder (Pleuronectes americanus) and American sand lance (Ammodytes americanus). Their combined density reached 8 m?3 and accounted for the winter peak in larvae. The seasonality of abundance of larval fish was strongly correlated with reported densities of copepod nauplii prey.  相似文献   

6.
In the presence of the first recorded red tide (Ptychodiscus brevis) outbreak in North Carolina, autumn 1987 recruitment of bay scallops (Argopecten irradians concentricus) in the state’s most productive scallop beds was a virtual failure. Recruitment averaged across all of Bogue and Back sounds was only 2% of the mean of three previous red tide-free (control) years. Only from central Core Sound northward, where the red tide occurred later and not as intensively, was bay scallop recruitment normal (93% of control years). Mortality of adult scallops from early December 1987 to late January 1988, while red tide was at bloom concentrations but fishing was prohibited, was 21%. No comparable natural mortality data exist for control years because intense fishing mortality in this period is confounded with natural mortality. Data on abundance of articulated pairs of empty shells strongly suggest that the red tide caused mortality of both adult and newly recruited bay scallops. Bay scallop recruitment in autumn 1988 again failed to restock the traditionally productive scallop beds in western Bogue Sound and in Back Sound, perhaps because the only concentrations of spawners surviving the red tide in central Core Sound and further north were too far distant for successful transport of bay scallop larvae in sufficient abundance to these traditional beds. This potential explanation implies continuing impact of the red tide on North Carolina’s bay scallop fishery until spawning populations increase in Back Sound and western Bogue Sound.  相似文献   

7.
The aim of this research was to evaluate the potential of six legumes: Medicago sativa L., Glycine max, Arachis hypogea, Lablab purpureus, Pheseolus vulgaris and Cajanus cajan to restore within a short period of time soil contaminated with 3% crude oil. The legumes in five replications were grown in crude oil-contaminated and crude oil-uncontaminated soil in a completely randomized design. Plants were assessed for seedling emergence, plant height and leaf number. GC–MS was used to analyze the residual crude oil from the rhizosphere of the legumes. Plant growth parameters were reduced significantly (P < 0.05) for legumes in contaminated soil compared to their controls. In the 4th week after planting (WAP), shoot height increased across the species up to the 8th WAP. However, in the 12 WAP no significant increase in the shoot of all species was observed. Two WAP legumes planted in contaminated soil had significantly (P < 0.05) higher leaf number than these planted in uncontaminated soil with the exception of M. sativa. In the 4th WAP, only A. hypogea and P. vulgaris had increased leaf number, while in the 6th WAP, only L. purpureus had increased leaf number and survived up to the 12th WAP while most of the legumes species died. Chromatographic profiles indicated 100% degradation of the oil fractions in C. cajan and L. purpureus after 90 days. For other legumes however, greater losses of crude oil fractions C1–C10 and C10–C20 were indicated in rhizosphere soil of P. vulgaris and G. max, respectively. The most effective removal (93.66%) of C21–C30 components was observed in G. max-planted soil even though vegetation was not established. The legumes especially C. cajan, L. purpureus and A. hypogea are promising candidates for phytoremediation of petroleum hydrocarbon-impacted soil.  相似文献   

8.
The seasonal abundance and spatial distribution of eggs and early larvae of the bay anchovy,Anchoa mitchilli, and the weakfish,Cynoscion regalis, were determined from plankton collections taken during 1971–1976 in the lower Chesapeake Bay. Eggs and larvae of the bay anchovy,Anchoa mitchilli, dominated the ichthyoplankton, making up 96% of the total eggs and 88% of all larvae taken. A comparison of egg and larval densities from the lower Chesapeake Bay to existing data from other East Coast estuaries suggested that Chesapeake Bay is a major center of spawning activity for this species.Anchoa mitchilli spawning commenced in May when mean water column temperatures approached 17°C and abruptly ceased after August. Eggs and early larvae presented a continuous distribution throughout the study area during these months. Eggs and larvae of several sciaenid species, especiallyC. regalis, ranked second in numerical abundance. Larval weakfish were consistently taken in late summer of each sampling year but peak abundance and distribution was observed in August 1971. Sciaenid eggs exhibited a distinct polyhaline distribution with greatest concentrations observed at the Chesapeake Bay entrance or along the Bay eastern margin. Analysis of sciaenid egg morphometry and larval occurrence suggested spawning activity of at least four species. Additional important species represented by eggs and/or larvae in the lower Chesapeake Bay wereHypsoblennius hentzi, Gobiosoma ginsburgi, Trinectes maculatus, Symphurus plagiusa andParalichthys dentatus with the remaining species occurring infrequently.  相似文献   

9.
Replicate groups of larvae from each of three female grass shrimp,Palaemonetes pugio, collected at each of six sites within Chesapeake Bay were reared in the laboratory to metamorphosis at 25°C, 25 ppt salinity. They were provided with approximately 300Artemia nauplii/larva/day. Sites were selected to provide both suspected Kepone® contaminated and non-contamined shrimp populations. A sample of eggs, adult females with and without eggs, and newly hatched larvae from each site were analyzed by Virginia Institute of Marine Science for Kepone as were postlarvae obtained through laboratory rearings. Females and eggs from the James River had highest concentrations of Kepone (0.63 and 0.47 ppm, respectively) with samples from the Lafayette River at the mouth of the James River having the second highest levels (0.04 and 0.4 ppm). Concentrations in ovigerous females and eggs in the populations most distant from the James (mouth of Potomac and upper Potomac River) were at or below the limits of detectability (0.001 to 0.015 ppm). In laboratory reared postlarvae from each site, concentrations of Kepone were undetectable. Despite these apparent differences in Kepone concentrations in the various populations we found no significant differences in larval survival, larval duration, or length of post-larvae attributable to site of origin. Highly significant differences in larval duration and size of post-larvae were attributable to parental variation.  相似文献   

10.
Experiments in 2.2 m3, in situ mesocosm enclosures indicate that black drum, Pogonias cromis, eggs and larvae potentially can survive in the lower Chesapeake Bay at ambient microzooplankton prey levels (≈200 prey 1?1) in the absence of predators. In growth experiments, larva mean growth rates to 10 d posthatch were similar (0.17 mm d?1 and 0.18 mm d?1) when fed at prey levels of 50 prey 1?1 and 200 prey 1?1. Individual growth rates, however, were more variable at 50 prey 1?1. Mortality rates also were comparable in 50 (27% d?1) and 200 (23% d?1) prey 1?1 enclosures. In a second experiment, the predation potentials of the hydromedusa Nemopsis bachei and the lobate ctenophore Mnemiopsis leidyi were estimated in relation to initial black drum egg prey density, presence of alternative <1 mm zooplankton prey, and estimated daily abundance of the jellyfish on the black drum spawning grounds. Mortality rates per medusa and ctenophore were similar (0.02–0.03 d?1), were not affected by presence of alternative prey, and were directly related to initial egg density. Results suggest that the gelatinous predators, especially the hydromedusa, could have cleared a high (≈38%) but variable fraction of the water column daily of fish eggs and yolk-sac larvae during the black drum spawning season. We hypothesize that the poor or episodic recruitment success of black drum in Chesapeake Bay results from a short spawning season that often coincides with abundance peaks of gelatinous predators and that predation on eggs and yolk-sac larvae may control recruitment.  相似文献   

11.
Surf smelt Hypomesus pretiosus are an important part of the Salish Sea food web and obligate beach spawners, yet little is known about the spatiotemporal distribution of spawning and beach characteristics related to spawning success. We counted smelt eggs at 51 sites around Camano Island, Puget Sound, Washington every 2?weeks for 1?year and at 13 of those 51 sites each month in the following year. At each site, we measured beach characteristics hypothesized to affect spawning habitat suitability as measured by egg abundance and mortality. Eggs were collected at 45 sites and pooled by month for analyses. Few sites (N?=?10, 19.6?%) contributed 87?% of total eggs and 89?% of all live eggs collected. Mean total egg counts at sites were higher (p?<?0.019) in Jul?CSep (1,790.7, SE?=?829.5) than in Jan?CMar (26.1, SE?=?10.2). Principal component and regression analyses suggested that aspect, fetch, solar radiation, and beach temperature predicted egg abundance but not mortality. Because a small proportion of sites appear to support most spawning activity, a conclusion consistent with year?2 egg counts, impacts to relatively few beaches could greatly affect surf smelt production.  相似文献   

12.
The effect of various concentrations of crude oil on fungal populations of soil was investigated for a period of 18 weeks using standard methods. Total fungal counts ranged from 26 to 143 χ 102 cfu/gsoil while counts of petroleum-utilizing fungi ranged from 2 to 102 χ 102 cfu/g soil. Analysis of variance and randomized complete block design of counts of total fungi and petroleum-utilizers showed high significant difference between the control and the oil treated soils at p? 0.05 level. Counts of petroleum-utilizers expressed as a percentage of the corresponding total fungal count of the soils ranged from 4.7 % to 58.8 %. Species of fourteen fungal genera were isolated from the soils. These include Alternaria,Aspergillus, Candida, Cephalosporium, Cladosporium, Fusarium, Geotrichum, Mucor, Penicillium, Rhizopus, Rhodotolura, Saccharomyces, Torulopsis and Trichoderma. Of these, ten were petroleum-utilizers and were all isolated from the control and 1 % oil treated soils. Only seven genera were isolated from the 5 % oil treated soil out of which five genera were petroleum-utilizers in both the 3 % and 5 % treatment. The decreasing order of occurrence of a variety of fungal genera (fungal diversity) of both total fungi and petroleum-utilizers is 0 % (control) > 0.5 % > 1 % > 3 % > 5 %. This order of fungal diversity is a reverse of the decreasing order of fungal counts of these same soils. This showed that higher concentrations of crude oil has adverse effect on fungal diversity while enhancing the population of a fewer fungi.  相似文献   

13.
The relationships between egg production (spawning behavior), larval growth and survival, and environmental conditions that larvae encounter were investigated in the Patuxent River tributary of Chesapeake Bay in 1991. Striped, bass (Morone saxatilis) eggs and larvae occurred predominantly above the salt front where conductivity was ≤800 μmhos cm?1. There were three prominent peaks in egg production, each coinciding with increasing temperatures. Estimated growth rates of 6-d, otolith-aged cohorts, which ranged from 0.15 mm d?1 to 0.22 mm d?1 (mean=0.17 mm d?1), were not demonstrated to differ significantly from each other. Observed zooplankton densities and temperature did not significantly affect growth rates. Stage-specific cumulative mortalities of combined cohorts were calculated for eggs (Zstage=0.20=18.1%), yolk-sac larvae (Zstage=5.80=99.7%), and first-feeding larvae (Zstage=2.95=94.8%). The very high mortality of yolk-sac larvae suggests that dynamic during this stage may have had a major impact on subsquent recruitment. Cohort-specific mortality rates of larvae were variable, ranging from Z=0.045 d?1 to 0.719 d?1, and were strongly temperature-dependent. Cohorts that experiented average temperature <15°C or >20°C during the first 25 d after hatching had significantly higher mortality rates than those which experienced intermediate temperatures. Estimated hatch-date frequencies of larvae ≥8 mm SL indicated goo, very good, and very low potential recruitments for cohorst spawned during early-season (April 2–11), mid-season (April 12–24) and late-season (April 25–May 5), respectively. Because seasonal temperature trends and fluctuations are unpredictable, striped bass females cannot select a spawning time that guarantees their offspring will be exposed to optimum temperatures. Consequently, selection may have occured for spawning over a broad range of temperatures and dates, a behavior insuring that some larval cohorts will encounter favorable temperatures.  相似文献   

14.
Integrated pest management programs are very important in the control of invertebrate pests within apple orchards. Many current integrated pest management strategies concentrate on specialist predatory species. However, generalist beneficial insects, such as several mite species, must also be fully researched for their potential in controlling pests. Previous research has shown that the generalist predatory mite Anystis baccarum (Linnaeus) can offer much potential in controlling invertebrate pests within Northern Irish apple orchards. However, apple growers have been mis-identifying this beneficial species as the economic pest European fruit tree red spider mite, Panonychus ulmi (Koch). As a result, unnecessary pesticide applications have been applied against what has now been confirmed as a beneficial species. To aid apple growers in the identification of A. baccarum, identification cards were produced. Positive uptake of the cards by many apple growers has resulted in correct identification of A. baccarum from P. ulmi, and therefore, a reduction in chemical pesticide applications. The benefits of A. baccarum within orchard ecosystems is discussed.  相似文献   

15.
Effects of petroleum covered substrate on intertidal oyster spat (Crassostrea virginica) set were measured at three intertidal elevations in a southeastern North Carolina estuary.Mercenaria mercenaria shells were coated with Bunker C crude oil or a 40∶1 mixture of gasoline: 2-cycle engine oil and placed intertidally for seven 13-d periods. Spat densities were significantly lower on oil treatments versus control and gas-treated shells in the high intertidal zone. This was principally attributed to an increased sediment coat on oiled shells. Maximum spat size was smaller on oil-treated shells at all elevations when compared to gas and control shells, indicating that setting may be delayed on oiled shell. For all experimental 13-d periods in the low intertidal zone and for three periods in the mid-tidal zone, barnacle densities (primarilyBalanus improvisus andB. eburneus) were significantly greater on oiled shells than on control shells.  相似文献   

16.
A weathered accumulation of turtle eggs, interpreted as remnants of a single clutch composed of at least 16 turtle eggs (MOR 710) from the Campanian (Upper Cretaceous) Judith River Formation of north-central Montana, USA, represents a new oospecies Testudoolithus zelenitskyae. This ootaxon is diagnosed by the following unique combination of characters: spherical eggs 34–39 mm in diameter, 660–760 μm thick eggshell, shell unit height-to-width ratio of 3.15:1–5.5:1, and domed shell units. Estimated egg mass indicates that the egg-laying adult likely possessed a carapace 35.0–54.4 cm in length. Similarities between T. zelenitskyae oosp. nov. and Adocus sp. eggs, along with comparable body size, suggest that this taxon might have produced MOR 710. One egg exhibits abnormal multilayered eggshell, likely resulting from prolonged egg retention by the female turtle. At least five of these eggs, including the multilayered specimen, preserve embryonic remains that demonstrate a late stage of embryonic development. This suggests that death occurred just prior to hatching.  相似文献   

17.
This work illustrates the toxicological impact of pesticide methyl parathion (MP) (dust—2 % active ingredient, a.i.) on growth and reproduction performance in tropical earthworms: Metaphire posthuma (endogeic), Lampito mauritii (anecic) and Allolobophora parva (epigeic). A total of three concentrations (a.i. g kg?1 dry test soil), 1.00 (T 1), 1.125 (T 2) and 2.25 (T 3) of MP, were applied in test substrate to examine the impact on mortality, individual live weight changes and reproduction patterns in test species over 60 days under laboratory conditions. MP caused significant mortality in all tested species, and median lethal dose (LD50) for L. mauritii, M. posthuma and A. parva was 24.85, 23.64 and 22.67 mg a.i., respectively. The individual live weight loss was 27.0–37.0 % in L. mauritii, 36.0–57.1 % in M. posthuma and 1.2–11.0 % in A. parva in different test concentrations. The pesticide-exposed worms produced less cocoons than control, but in L. mauritii, an unusual reproduction (hormesis) was recorded. Results suggested the species-specific toxicity of MP against tropical earthworms.  相似文献   

18.
Crude oil and its derivatives because of different events and accidents may cause pollution to the environment. A biological treatment is a novel technique that uses microorganisms to remove or neutralize pollutants from a contaminated site. Oil-contaminated soils were sampled, after isolating of soil bacteria, using quantitative and qualitative screening, biosurfactant-producing bacteria were identified and environmental factors on the growth of bacteria and biosurfactant were investigated. In this study, the Bacillus subtilis was identified as the best biosurfactant-producing strain which has the ability to grow in environments with high salinity and temperature and pH > 5. The produced biosurfactant from B. subtilis is stable to changes in temperature and salt concentration and pH (in the range of 5–12).The B. subtilis also showed that they are able to biodegrade aliphatic alkanes. The B. subtilis has necessary potential for bioremediation of oil pollution in the environment.  相似文献   

19.
Egg deposition by the intertidal spawning fish Atlantic silverside (Menidia menidia) was compared among six shoreline types (Spartina alterniflora, Phragmites australis, sandy beach, riprap, riprap-sill, and bulkhead) and various substrates. In spring 2010, M. menidia egg density was measured daily near Roosevelt Inlet, Delaware Bay, USA. Over 3,000,000 eggs were collected during 50 sampling days. Eggs were deposited at all six shoreline types, with >93?% of eggs collected from S. alterniflora shorelines. Choice of substrate for egg attachment was similar across shoreline types with >91?% of eggs collected from filaments of the green alga Enteromorpha spp., a disproportionately high utilization rate in comparison with Enteromorpha spp.'s relative coverage. This study demonstrates that S. alterniflora shoreline, in association with Enteromorpha spp., is the preferred spawning habitat for M. menidia and that hardened shorelines and shorelines inhabited by P. australis support substantially reduced egg densities.  相似文献   

20.
Bioremediation of oil spillage in soils using consortia of microbes beckons much exploration. The present study involves bioremediation of oil-contaminated soils from north Chennai, India, using indigenous microbial consortia. Totally, 32 positive oil degrading isolates were obtained from 3 different locations, i.e., petrol filling stations, automobile workshops and oil refineries. Substrate utilization patterns of individual isolates and the consortial sets were observed. Mixture of three common hydrocarbons (petrol, diesel and engine oil) was used for studies. The substrate oil utilized by consortia was taken for thin-layer and column chromatography which perfectly resulted in varied fractions of oil compared to the unused oil as control. The best consortia were used directly for bioremediation experiment. Three different oil-contaminated soils were used and bioremediation patterns were observed. The rate of bioremediation differed within soils, nevertheless all soils were almost 100 % reclaimed within 30 days. Bioremediation kinetics showed that the process corresponds to first-order kinetics and kinetic constants for the different soils ranged from 0.051 to 0.077/day. Assessment of detoxification of acute phytotoxicity owing to the pollutant oil was done, and results observed were significant. An increase of 25, 300 and 212 % in germination index, average growth index and sustenance index, respectively, of Trigonella foenum-graecum Linn. in treated soils was observed, compared to untreated soils. Thus, this study confirmed that microbes in ‘Consortial Union’ serve as better treating agents in bioremediation of oil-contaminated soils than individual microorganisms.  相似文献   

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