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At least 343 records · Page 19Linked to original sources
PubMed1996

Economic impact of black flies (Diptera:Simuliidae) in South Carolina and development of a localized suppression program.

The membership of a private golf club in South Carolina's Piedmont Physiographic Region was surveyed to determine perceptions regarding local black fly populations and the effects of these populations on golfing habits. The economic impact of black fly annoyance at this club was estimated to be $27,202. Adult monitoring indicated that the pest species were members of the Simulium jenningsi group; larval monitoring identified the Enoree River, Laurens County, as the primary source of the pest species. A localized suppression program was initiated during the late summer of 1994 and continued through the fall of 1995. Four larvicide applications were conducted in 1994 and 11 in 1995, using the biological insecticide Vectobac. Larval mortalities of 94.5 and 97% were produced during 1994 and 1995, respectively. Adult black fly populations were reduced 92 and 88% during 1994 and 1995, respectively, from pre-program populations. Improvements for future suppression programs are proposed.

Animals↗
PubMed1996

Control of pest blackflies (Diptera:Simuliidae) along the Orange River, South Africa: 1990-1995.

The efficacy of Bacillus thuringiensis var. israelensis (B.t.i.) and temephos in controlling the pest blackfly Simulium chutteri Lewis along the middle Orange River between 1990 and 1995, was assessed. Larvicides were applied by helicopter to rapids and riffles between Hopetown and Onseepkans, a river distance of 807 km. Larvicidal efficacy was based on the change in larval abundance at selected sites before and after each treatment. The success of the control programme was assessed independently by local farmers, who ranked adult blackfly annoyance on a 4-point scale. Before treatment, blackfly annoyance showed consistent peaks in spring, and sometimes in autumn, and levels were unacceptably high for between 17 and 36 weeks of the year. After treatment started, blackfly annoyance levels were reduced significantly. The number of annual treatments necessary to reduce blackfly annoyance to acceptable levels was highly variable (3-13), and depended on river conditions, as well as the efficacy and timing of each treatment. During low-flow conditions (< 50 m3/s), applications became increasingly difficult in braided sections of the river, and dosage calculations were inaccurate because of local abstraction and return flows. Both larvicides worked well in winter (water temperature 11-13 degrees C). Control of the spring outbreak can be planned well in advance, with the first treatment starting in mid July. A flexible protocol is required to control outbreaks at other times of the year. We recommended the use of B.t.i. for most applications, with increased dosages during algal blooms (> 1500 cells/ml). The use of temphos in the Orange River should be considered only during algal blooms or when flows exceed 300 m3/s. We conclude that helicopter application of larvicides is an effective method or controlling blackflies, along the middle Orange River.

Animals↗
PubMedDate not supplied

[The relationship between the population count of black fly larvae and pupae (Simuliidae) in bodies of water and the number of attacking females].

Species of black flies, which develop in abundance in water bodies of Lower Priamurje and are potentially capable of bloodsucking, have not been registered near the blood donors. Only a few number of species developing in water attack for bloodsucking that apparently depends on unfavourable conditions of the larval development. A part of emerging females do not possess sufficient nourishing resources for completion of their gonotrophic cycle and need an additional bloodsucking. Of 35 registered species (27 of them possess morphological devices for bloodsucking) only 11 species attack. 4 species (Byssodon maculata ussuriana, Gnus malyshevi albipes, G. pavlovskii, Prosimulium ex gr. hirtipes) are mass bloodsuckers.

Animals↗
PubMed1996

Development of Erynia conica (Zygomycetes: Entomophthorales) on the Cuticle of the Adult Black Flies Simulium rostratum and Simulium decorum (Diptera: Simuliidae)

Aerial conidia of Erynia conica were showered onto the wings of susceptible and nonsusceptible black fly, Simulium rostratum and Simulium decorum, respectively. Secondary type 2 conidia as opposed to type 1 conidia and primary conidia invaded the wings of S. rostratum. The invasion process on both sexes of the host species was rapid, with 40% of the conidia germinating during the 2 hr that the wings were showered with conidia. Approximately 24% of total spores developed appressoria close to the parental spore and 79% of the appressoria developed penetration pegs in the cuticle by 9 hr postinoculation. These conidia also germinated (71%) on the abdominal cuticle of S. rostratum by 6 hr, but no appressoria or penetration tubes were noted throughout the duration of the study. On S. decorum, the invasive conidia exhibited delayed germination and neither formed appressoria nor did they invade the wings, but rather produced high levels of tertiary type 1 spores (26%). Cuticular lipids played a role in the infection process by triggering appressorium formation on the host, but did not seem to act as an inhibitory factor(s) on the nonhost.

Journal Article↗
PubMed1996

An Investigation of Harpellales (Trichomycetes) in New York State Blackflies (Diptera: Simuliidae)

This research project investigates the distribution and prevalence of trichomycete fungi present in blackfly larvae and adults in the region of Cambridge, New York. In blackfly larvae, two genera of Harpellaceae, Stachylina and Harpella, were observed in midguts, and four genera of Legeriomycetaceae-Pennella, Genistellospora, Simuliomyces, and Smittium-in hindguts, with a total of seven species recorded. This is the first published report of Stachylina spp. in blackflies. Field data indicated that sampling date, host species, and location were all important variables affecting trichomycete prevalence in larvae. We report the successful laboratory infection of blackfly larvae with in vitro cultured Smittium simulii, and production of H. melusinae and G. homothallica trichospores from cysts dissected from the ovaries of infected flies.

Journal Article↗
PubMed2000

Utility of the mitochondrial cytochrome oxidase II gene for resolving relationships among black flies (Diptera: simuliidae).

The complete mitochondrial cytochrome oxidase II gene was sequenced from 17 black flies, representing 13 putative species, and used to infer phylogenetic relationships. A midge (Paratanytarsus sp.) and three mosquitoes (Aedes aegypti, Anopheles quadrimaculatus, and Culex quinquefasciatus) were used as outgroup taxa. All outgroup taxa were highly divergent from black flies. Phylogenetic trees based on weighted parsimony (a priori and a posteriori), maximum likelihood, and neighbor-joining (log-determinant distances) differed topologically, with deeper nodes being the least well-supported. All analyses supported current classification into species groups but relationships among those groups were poorly resolved. The majority of phylogenetic signal came from closely related sister taxa. The CO-II gene may be useful for exploring relationships at or below the subgeneric level, but is of questionable value at higher taxonomic levels. The weighting method employed gave phylogenetic results similar to those reported by other authors for other insect CO-II data sets. A best estimate of phylogenetic relationships based on the CO-II gene is presented and discussed in relation to current black fly classification.

Amino Acid Sequence↗
PubMed1975

C banding in polytene chromosomes of Simulium ornatipes and S. melatum (Diptera: Simuliidae).

Polytene and mitotic chromosomes of Simulium ornatipes and S. melatum were subjected to C banding procedures. In both species polytene chromosomes consistently show C banding of centromere regions, telomeres, nucleolar organiser and, unexpectedly, numerous interstitial sites. The interstitial C banding sites correspond to morphologically single polytene bands. Their response is graded and independent of band size. Interstitial C bands in S. ornatipes are scattered throughout the complement, whereas in S. melatum they are clustered. Supernumerary heterochromatic segments in S. ornatipes also exhibit strong C banding and inverted segments can differ from standard in C banding pattern. -- Mitotic chromosomes of both species show a single centric C band with indications of two weak interstitial bands in S. ornatipes, suggesting that many C band regions, detectable in polytene chromosomes, are not resolved by present techniques in mitotic chromosomes. -- Contrary to current opinion that C banding is diagnostic for constitutive heterochromatin, the interstitial C band sites of polytene chromosomes are regarded as euchromatic. Conversely, the heterochromatic pericentric regions of S. ornatipes are not C banded. -- It appears that polytene chromosomes offer a promising system for the elucidation of C banding mechanisms.

Animals↗
PubMed1975

Achiasmate meiosis and centromere shift in Eusimulium aureum (Diptera-Simuliidae).

Light and electronmicroscope studies indicate that Eusimulium aureum (n equals 2 metacentrics) is male-achiasmate. Supporting evidence for achiasmate meiosis includes lack of recombination between, I) widely separated differential segments of X and Y chromosomes and 2) linked autosomal inversions. In sibling C, chromosome II exists in an alternate "neoacrocentric" form interpreted as originating through the three-break shift of a small segment including centromere and nucleolar organizer. Male-achiasmate meiosis appears to be a prerequisite for the establishment of rearrangements that include large displacements of the centromere. This suggestion is supported by a correlation between achiasmate male meiosis and the fixation of gross pericentric changes in a number of other black fly species.

Animals↗
PubMed1976

Polytene chromosomes in pupal and adult blackflies (Diptera: Simuliidae).

A number of pupal and adult tissues of eight Australian blackfly species representing three genera, Austrosimulium, Cnephia and Simulium, were examined for the presence of polytene chromosomes. Banded polytene chromosomes were found in malpighian tubules, hind gut, fat body, and ovary, but only those from the malpighian tubules of female adults and pupae were of good quality. A detailed comparison of polytene chromosomes from larval salivary glands and adult malpighian tubules was made in S. ornatipes and, to a limited extent, in S. melatum. The banding patterns of chromosomes from both tissues were found to be identical with minor differences in puffing patterns in S. ornatipes and chromocenter characteristics in S. melatum. A survey of the remaining six species shows five of them to have malpighian chromosomes suitable for detailed cytological analysis. Simultaneous studies of larval, pupal and adult polytene chromosome systems offer a novel approach to the analysis of population problems in blackflies. The ability to recognise sibling species in adults also has potential practical significance in efforts to control vectors of onchocerciasis.

Animals↗
PubMed2003

Influences of a laboratory diet and natural seston on the bioavailability of carbaryl, chlorpyrifos, and malathion to black fly larvae (Diptera: Simuliidae) in an acute toxicity test.

To determine the effects organic food particles can have on insecticide bioavailability, two food types, a laboratory diet and dried, natural seston, were evaluated using black fly larvae, Simulium virtatum Zetterstedt cytospecies IS-7, in a 24-h orbital shaker toxicity test. The bioavailability of all three insecticides was significantly altered when diet concentrations in the flasks were > or = 150 mg/L. Chlorpyrifos availability decreased, whereas carbaryl and malathion availability increased. Dried, natural seston had little effect on the bioavailability of these insecticides except in carbaryl-dosed larvae where mortality was significantly increased when seston concentrations were 150 mg/L in the flasks. Differences in insecticide bioavailability between the two food types in these experiments might have been related to the particle size and organic carbon content of the two materials. Laboratory diet particles were significantly smaller (11.7 +/- 0.5 microm) and had a significantly greater organic carbon content (26.4%) than the seston particles (30.9 +/- 3.3 microm; 1.1%). These results suggest that the concentration, as well as the physical and chemical component of the food source, are important factors in determining the effects of food on insecticide bioavailability in aquatic systems.

Animal Feed↗