Showing papers on "Infestation published in 1976"
94 citations
TL;DR: The efficiency of the parasite is greatly impaired during the short days and low light intensities of the late winter months and alternative methods of dealing with early whitefly infestations, including the use of chemicals, are discussed.
Abstract: SUMMARY
During 1969/74 different methods of using the parasite Encarsia formosa to control whitefly infestations on tomatoes in glasshouses have been evaluated commercially. The most effective control was achieved by the Glasshouse Crops Research Institute (GCRI) programme of timed parasite introductions at rates totalling 120000 parasites per ha (48000/acre) following the pre-establishment of a low, evenly distributed infestation of the pest throughout the crop. Other methods, including the regular introduction of parasites after planting in anticipation of a whitefly infestation or starting when the first whiteflies appear on the plants, are also described. These multiple introduction (‘dribble’) methods, gave mostly satisfactory control but were less predictable.
The efficiency of the parasite is greatly impaired during the short days and low light intensities of the late winter months and alternative methods of dealing with early whitefly infestations, including the use of chemicals, are discussed.
52 citations
01 Jan 1976
47 citations
TL;DR: Recommendations for control based on the results of the investigation included procedures for identifying and processing cases, distributing free pediculicides, continuing surveillance, educating school personnel and parents on how to control the parasite.
Abstract: An outbreak of head lice infestation (pediculosis) occurred in elementary school children in Barrow County, Georgia, in January 1974. An investigation was initiated to define the magnitude of the outbreak, determine factors that contribute to transmission, and disseminate information on control. All elementary school children in the county were examined for head lice and answered a questionnaire. Fifty-three (3%) of 1,783 white pupils were infested, but none of the 500 black pupils was infested. Distribution of infestation in the white pupils was influenced by grade, bed-sharing, socioeconomic status, infestation of other family members, crowding in the home, and family size; distribution was not influenced by hair length or the sex of the pupil. Recommendations for control based on the results of the investigation included procedures for identifying and processing cases, distributing free pediculicides, continuing surveillance, educating school personnel and parents on how to control the parasite.
40 citations
TL;DR: Evidence from the disproportionate frequencies and levels of infestation on males and females in clusters suggests the existence of a host factor produced by females which may attract flies and thus enhance their hostfinding success.
Abstract: The frequency and levels of infestation of the bat fly Trichobius corynorhini Cockerell on its normal host Plecotus townsendii Cooper are examined. A direct relationship between winter host density and levels of bat fly infestation is demonstrated. Frequency and levels of infestation are greatest on females. No differences in frequency or levels of infestation are shown for solitary and clustered female hosts, although clustered males are more frequently and heavily parasitized than solitary males. It is hypothesized that higher frequencies and levels of bat fly infestation on males in winter are coincident with a shift from a solitary behavior of males in summer to an increase in cluster frequency and association with females in autumn and winter. Apparent movements of bat flies from more heavily infested females to male hosts may reduce intraspecific competition and thus permit optimal utilization of food resources (blood) when both sexes of the host are together in hibernation and blood from the host is potentially limiting due to a decrease in peripheral circulation. Evidence from the disproportionate frequencies and levels of infestation on males and females in clusters suggests the existence of a host factor produced by females which may attract flies and thus enhance their hostfinding success. This may be necessary to insure reproductive success of flies in the warm summer months owing to the propensity for males to roost singly at this time and for females to form nursery aggregations.
23 citations
TL;DR: The effect of sprinkler irrigation and wide ridging on potato infestation by the potato tuber moth Phthorimaea operculella Zell.
Abstract: In a field trial at Pukekohe the effect of sprinkler irrigation and wide ridging (91 cm) on potato infestation by the potato tuber moth Phthorimaea operculella Zell., Lepidoptera, Gelechiidae was assessed in a season of unusually low rainfall. Infestation of table grade tubers was 10% under sprinkler irrigation compared with 86% under no irrigation. Irrigation increased tuber yield four-fold. The combined effects of irrigation on tuber infestation plus yield produced a 27.9-fold increase in marketable potatoes, from 1513 kg/ha to 41 297 kg/ha. Wide ridging was associated with reduced infestation of table grade tubers. Closer spacing of seed to maintain correct plant density per hectare did not affect tuber yield. No interaction between irrigation and row width was detected. Irrigation reduced foliage-mining intensity (number of miners per unit available leaf). As the crop matured, foliage was denser under irrigation, and the actual population level (number of miners per unit land area) was higher...
22 citations
Journal Article•
TL;DR: The number of hydatid cyst infestation amongst 15,691 corpses is as follows: 881 out of 12,311 sheep and goats, 378 out of 3380 cattle and camels.
Abstract: We have collected all the reported cases of Echinococcus cysts recovered in every surgical ward in Mashhad since their establishment. At the same time we searched corpses of livestock which had been slaughtered in Khorassan's slaughter houses in different days since 1969 for evidence of cysts, and also dogs, 2 wolves, 4 jackals and 11 foxes which had been killed with strychnine, for adult worms. Occurrence of hydatid cyst infestation was found in 478 reports of surgical operations amongst 43,196 cases operated for various diagnosis including hydatidosis. The number of hydatid cyst infestation amongst 15,691 corpses is as follows: 881 out of 12,311 sheep and goats, 378 out of 3380 cattle and camels. The dogs' infestation was rather high as we found adult Echinococcus worms in 50 out of the examined 266, which gives a percentage of 18.79. But no worms could be found in the 2 wolves, 4 jackals and 11 foxes which were examined. All the adult worms examined were Echinococcus granulosus.
16 citations
TL;DR: Botfly infestation was analyzed in 1319 small mammals from varied habitats and elevations in upland Virginia, 1972-1974, and observations suggested that many infested adults were non-reproductive.
Abstract: Botfly infestation was analyzed in 1319 small mammals from varied habitats and elevations in upland Virginia, 1972-1974. Adult Cuterebra fontinella were reared from bots infesting the woodmouse (Peromyscus leucopus). Of 651 woodmice, 199 (30.6%) were infested at least once. The season of bot infestation extended from May through November of all years, with peak prevalence (mean 42.2%) in August. Infestation in woodmice was general over a 2000 km2 study area during peak months. Significantly greater prevalence (P<0.001) was seen in forested and brushy habitat (39.9%) compared with old fields (2.6%). Higher prevalence (P<0.01) was found in males than in females, and in postjuveniles compared to adults. Greatest overall prevalence (39.1%) was in postjuvenile males. Most warble sites (98%) were inguinal, and observations suggested that many infested adults were non-reproductive. Mean burden (1.27) was independent of host age, sex, habitat, and month of capture. Multi-infestations occurred in 23% of the affect...
15 citations
Journal Article•
TL;DR: The Otopheidomenids were found to parasitize 30 genera and 47 species and subspecies of sphingid moths (Lepidoptera) in various countries located between the latitude of 30°N and 30°S.
Abstract: The Otopheidomenids (Acarina: Otopheidomenidae) were found to parasitize 30 genera and 47 species and subspecies of sphingid moths (Lepidoptera) in various countries located between the latitude of 30°N and 30°S. The percentage of infestation in the museum preserved moths was found to be 1.0 %. However, the percentage of infestation was found to be 28.6 % in the moths of iVlalagasy and Honduras and 33.3 % in the moths of Surinam. All the lite stages were found on the same host mostly in the tympanic area or metathoracic-Ist abdominal cavity.
14 citations
TL;DR: In a field study 20 potato cultivars were compared for relative levels of foliar and tuber infestation caused by the potato tuber moth (Phthorimaea operculella (Zeller)). All became seriously infested and showed no evidence of resistance as mentioned in this paper.
Abstract: In a field study 20 potato cultivars were compared for relative levels of foliar and tuber infestation caused by the potato tuber moth (Phthorimaea operculella (Zeller)). All became seriously infested and showed no evidence of resistance. ‘Wha’, ‘Ono’, and ‘1584c10’ were the least seriously affected cultivars when assigned a performance rank based on a combination of foliage mining intensity, level of table grade tuber infestation, and total tuber yield. Varieties with a prolonged upright growth habit and few leaves close to the soil surface sustained low foliage mining populations. Light tuber infestation was also associated with plant growth habit, such as deeper tuber set, rather than with true resistance.
TL;DR: Six hundred clones of potato, Solanum tuberosum L. andigena (Juz. & Buk.), a tetraploid subspecies cultivated in the Andes of South America, were screened for resistance to the green peach aphid, Myzus persicae (Sulzer), and the potato Aphid, Macrosiphum euphorbiae (Thomas).
Abstract: Six hundred clones of potato, Solanum tuberosum L. andigena (Juz. & Buk.), a tetraploid subspecies cultivated in the Andes of South America, were screened for resistance to the green peach aphid, Myzus persicae (Sulzer), and the potato aphid, Macrosiphum euphorbiae (Thomas). After one unreplicated and 2 replicated clonal selection cycles, resistance to M. persicae was confirmed in 6 clones and to M. euphorbiae in 13 clones. Five clones (N503-141, N503-246, N551-17, N551-18, N558-26) were resistant to both species. Also, 382 clones of S. t. andigena were screened for resistance to nymphal infestation and feeding damage (hopperburn) by the potato leafhopper, Empoasca fabae (Harris). After 3 selection cycles, 7 clones were resistant to infestation and 7 clones were resistant to hopperburn. Three clones (N511-14, N551-15, N551-16) were resistant to both hopperburn and nymphal infestation. Another clone, N502-26, was resistant to hopperburn despite relatively large nymphal infestations. Resistance to nymphal infestation also was confirmed for 7 clones of an agronomically-advanced population of S. tuberosum tuberosum (L.)
None of the clones were resistant to all 3 target pests.
TL;DR: The study confirms the usefulness as well as the limitations of the presence of parasitic water mites as a rapid means of age-grading female mosquitoes, and suggests several new applications.
Abstract: The parasitic larvae of two species of water mites were studied on resting and biting Anopheles implexus (Theo.) from the Zika Forest near Entebbe, Uganda. Details are given of the mites' morphology, positions of attachment, growth stages and visible effects on hosts. Living larvae of the more numerous mite species (designated as species F, Limnesiidae) were only moderately reliable indicators of the nulliparous state of female hosts, whereas those of the other species (species G, Arrenuridae) were more reliable nullipar indicators, evidently owing to their far more rapid development. The presence of living larvae of either species not completely full-grown denoted the nulliparous state of female hosts with certainty. Male mosquitoes showed consistently lower infestation rates than females from the same resting samples, but the incidence of the different growth classes of species F indicated that these mites departed from hosts of either sex with equal facility and therefore regardless of whether the hosts returned to oviposition sites or not. Frequency distributions of species F on each host sex fitted most closely to highly clumped negative binomials, and biological interpretation of patterns of decline in mite numbers on females in successive Sella's stage groups, and other data, provided evidence of there being at most a negligible amount of mite-mediated host mortality.The study confirms the usefulness as well as the limitations of the presence of parasitic water mites as a rapid means of age-grading female mosquitoes, and suggests several new applications.
TL;DR: There was good correlation between the beetle index and the numbers of individuals of A.sylvaticus infested; this relationship resembled that found within certain host/ectoparasite relationships.
Abstract: 1
In a mixed small mammal community L.testaceus was found to infest A.sylvaticus more frequently than either C.glareolus or M.agrestis.
2
Male and female rodents carried similar numbers of the beetle.
3
Peak infestation on A.sylvaticus occurred during spring and summer suggesting a single major emergence period.
4
There was good correlation between the beetle index and the numbers of individuals of A.sylvaticus infested; this relationship resembled that found within certain host/ectoparasite relationships.
TL;DR: In field-plot tests on Heliothis armigera (Hb.) on Sorghum in the Ord River Valley in the north of Western Australia in 1971-73, oviposition, larval numbers, and grain damage were investigated in 3 varieties of sorghum with different head densities, finding some evidence that infestation might be adequately controlled by natural enemies.
Abstract: In field-plot tests on Heliothis armigera (Hb.) on sorghum in the Ord River Valley in the north of Western Australia in 1971-73, oviposition, larval numbers, and grain damage were investigated in 3 varieties of sorghum with different head densities. The total numbers of eggs laid were similar in the 3 varieties, but larval infestation was higher in a very dense-headed variety (Pickett 932045) than in a semi-dense headed one (RS610) and an open-headed one (E57). Greater losses per larva were estimated with varieties E57 and Pickett 932045 than for RS610, where lesser susceptibility was associated with ability to compensate, mainly by increased grain size, for grain loss. There was some evidence that infestation might be adequately controlled by natural enemies (including Trichogramma australicum Gir. and Microgaster sp.) when chemical control of other pests (including locusts) is not necessary, and where spray drift from other crops does not occur. Where chemical control is necessary, the precise timing of application in relation to hatching of the eggs is important.ADDITIONAL ABSTRACT:In trials in 1971-3 in the Ord River valley, N. Western Australia grain damage by H. armigera was studied in 3 sorghum cultivars of different panicle densities. Larval infestation was highest on (a) the very dense-panicled cv. Pickett 932045 and was similar in (b) the semi-dense-panicled cv. RS610 and (c) the open-panicled cv. E57. Grain losses/larva were 5.4, 7.9 and 8.4, in (b), (c) and (a), respectively. Mean grain yield losses of untreated plots compared with those given applications of endosulfan or Orthene [acephate] were 93.8, 132.8 and 148.3 g/m2 in (b), (c) and (a), respectively. In 1971-2, grain yield loss in untreated plots was significantly less in (b) than in (a) or (c). 100-grain weight in (a) and (c) was similar in untreated plots and those given pesticides, but was higher in untreated than treated plots in (b).ADDITIONAL ABSTRACT:In trials in 1971-3 in the Ord River valley, N. Western Australia grain damage by H. armigera was studied in 3 sorghum cultivars of different panicle densities. Larval infestation was highest on (a) the very dense-panicled cv. Pickett 932045 and was similar in (b) the semi-dense-panicled cv. RS610 and (c) the open-panicled cv. E57. Grain losses/larva were 5.4, 7.9 and 8.4, in (b), (c) and (a), respectively. Mean grain yield losses of untreated plots compared with those given applications of endosulfan or Orthene [acephate] were 93.8, 132.8 and 148.3 g/m2 in (b), (c) and (a), respectively. In 1971-2, grain yield loss in untreated plots was significantly less in (b) than in (a) or (c). 100-grain weight in (a) and (c) was similar in untreated plots and those given pesticides, but was higher in untreated than treated plots in (b)
Journal Article•
TL;DR: The incidence of infestation with H. truncatum and the number of ticks of this species on infested animals were lowest in areas where plentiful surface water was responsible for an increase in humidity.
Abstract: In November 1972, 93 out of 100 African buffalo from 3 areas in Ngamiland, Botswana, were found to be infested with ticks. The tick species present and the percentage of buffalo infested by each were: Hyalomma truncatum (63%), H. rufipes (54%), Rhipicephalus evertsi evertsi (68%), R. tricuspis (11%), R. simus (4%) and Boophilus decoloratus (1%). The mean number of ticks per animal was 8,6 (standard deviation +/-4,1), representing a mean of 6,5+/-3,4 male and 2,1+/-1,9 female ticks. The incidence of infestation with H. truncatum and the number of ticks of this species on infested animals were lowest in areas where plentiful surface water was responsible for an increase in humidity.
01 Jan 1976
TL;DR: During the May-October hunting seasons in 11 hunting districts of southern Germany, 213 roe bucks were examined for carcass weight and the presence of nasal bot grubs (Cephenemyia stimuulator).
Abstract: During the May-October hunting seasons in 11 hunting districts of southern Germany, 213 roe bucks (Capreolus capreolus) were examined for carcass weight and the presence of nasal bot grubs (Cephenemyia stimuulator). The percent of animals infested by month from May to October was 71%, 61%, 60%, 28%, 40% and 33%. The average infestation rate was 11 parasites per roe in June and 3 grubs per roe in October. There was a marked relationship between carcass weight and rate of infestation. A low infestation rate of 1 to 5 nasal bot larvae occurrec in animals whose weight was 10% below normal. Animals whose carcass weight was 30% below normal had infestations of 21–52 larvae at the time of killing.
TL;DR: Fewer adult female ticks matured on the daily infested animals than on the intermittently infested animal during the treatment period, but animals developed a similar resistance level whether infested with either technique.
Abstract: The development of resistance to Boophilus microplus by cattle was studied using sets of cattle twins, in stalls. One twin from each set received 3 infestations of 40,000 larvae and the other a continuous infestation of 1,000 larvae a day over the same period. Sets of twins were then challenged with 1,000 larvae a day for 40 days and 2 field infestations of 20,000 larvae. Correlations of ranking for resistance made at 40-day periods during daily infestations of 1,000 larval ticks or for corresponding intermittent infestations of 40,000 larvae were low until animals had received 120,000 larvae. Thereafter irrespective of method of infestation correlations of ranking were relatively high (r = 0.61-0.96) between periods of infestations or method of infestation including 2 field infestations. Fewer adult female ticks matured on the daily infested animals than on the intermittently infested animals during the treatment period, but animals developed a similar resistance level whether infested with either technique.
01 May 1976
TL;DR: The trends of infestation of Haplothrips ganglbaueri on Oryza sativa and the weed Echinochloa crusgalli in paddy fields are discussed, along with its biological and taxonomical aspects.
Abstract: The trends of infestation ofHaplothrips ganglbaueri onOryza sativa and the weedEchinochloa crusgalli in paddy fields are discussed, along with its biological and taxonomical aspects.
TL;DR: Beetles of an Acylomus sp.
Abstract: Beetles of an Acylomus sp. near ergoti were found feeding on and developing in sclerotia of ergot ( Claviceps purpurea ). Infestation of the sclerotia was as high as 77% , and reduction in stromata initiation due to feeding damage ranged from 6–46%.
TL;DR: Yield losses sustained by the larger fruited improved cultivars exceed those in native groves exposed to the same level of weevil infestation.
Abstract: The number of pecan weevil larvae per infested pecan is apparently independent of nut size and weight, kernel weight and the infestation level of the nuts in the tree. Consequently, yield losses sustained by the larger fruited improved cultivars exceed those in native groves exposed to the same level of weevil infestation.
01 Jan 1976
TL;DR: The jejunal morphological aspect improved significantly indicating the pathogenetic role of intestinal parasites in the development of selective mal absorption in patients having intestinal infestation with giardia or with parasitic associations.
Abstract: Forty adult patients having intestinal infestation with giardia or with parasitic associations, such as giardia-strongiloides, giardia-taenia solium, were subjected to morphological explorations, iron and vitamin B12 absorption tests, steatorrhea assay and serological tests, before treatment as well as six months and one year after eradication of the infection. On admittance, jejunal morphological lesions were noted only in 15 cases especially in associated infestation, iron depletion in six patients, vitamin B12 malabsorption in five patients and steatorrhea only in two cases. After the lapse of six months and one year, respectively, all the tests ranged within normal values, and the jejunal morphological aspect improved significantly indicating the pathogenetic role of intestinal parasites in the development of selective malabsorption.
TL;DR: From July through November 1972, 4 areas in Fort Bend Co., TX, the center of infestation of Solenopsis invicta Buren in the central coastal prairies of East Texas, were surveyed for infestation, showing this county to be heavily infested with red imported fire ants.
Abstract: From July through November 1972, 4 areas in Fort Bend Co., TX, the center of infestation of Solenopsis invicta Buren in the central coastal prairies of East Texas, were surveyed for infestation. Particular attention was given to type of habitat, vegetation, and degree of infestation. The survey showed this county to be heavily infested. The red imported fire ants were found in pastureland, cropland, and woodland, but they were more common in pastureland. An aerial application of standard (4X) mirex bait was made to 4 established research blocks in Fort Bend Co. in the fall of 1972 to control S. invicta . The total pretreatment count of mounds was 2169, an avg 542 mounds/block. Two blocks, treated when air and soil temperatures were favorable, showed good control (100–99%) at 8–8½ mo post-treatment. Two blocks, treated as temperatures began to drop, showed a slower kill and lesser control (88–93%) at 10 mo posttreatment.
TL;DR: During the summer of 1974, immature Gulf Coast tick infestation levels were monitored on adult meadowlarks in Oklahoma and observations were made on the influence of tick parasitism on blood composition and weights of the birds.
Abstract: During the summer of 1974, immature Gulf Coast tick infestation levels were monitored on adult meadowlarks in Oklahoma and observations were made on the influence of tick parasitism on blood composition and weights of the birds. The highest tick infestations occurred from late June through August. Although blood parameters, except packed cell volume, and weights of the birds were found significantly different over the summer, no correlations existed between any of these parameters and tick infestation.
01 Jan 1976
TL;DR: A brief infestation of near outbreak proportions by larvae of Hylemya extremitata Malloch occurred on bromegrass, Bromus inermis Leyss and B .
Abstract: A brief infestation of near outbreak proportions by larvae of Hylemya extremitata Malloch occurred on bromegrass, Bromus inermis Leyss and B . pumpellianus Scribn., at Beaverlodge, Alta., in 1971–72. Larvae feeding primarily on meristematic tissue caused injury to as many as 20% of the grass tillers examined. Mature larvae overwintered within the tillers. Adults emerged in mid-June. Descriptions are given of the three larval stages of this species and of mature larvae of the first two of the following four species of Chloropidae, which were also found living within the bromegrass: Olcella provocans (Becker), Oscinella coxendix (Fitch), Oscinella incerta Becker, and Conioscinella melancholica Becker.
Journal Article•
TL;DR: An epidemiological study of ovine helminthiasis was carried out in Itaqui county, Rio Grande do Sul, Brazil, from 1966 to 1972, showing that a minimum of six anti-helminthic drenches are theoretically needed each year to maintain a sub-clinical level of parasitism in the flocks of It Aqui.
Abstract: An epidemiological study of ovine helminthiasis was carried out in Itaqui county, Rio Grande do Sul, Brazil, from 1966 to 1972 The mean monthly incidence of worms was correlated with the animal age the biology of the parasite, the season and climatic data A high prevalence of Haemonchus contortus, Trichostrongylus sp and Oesophagostomum columbianum was verified showing that these species are the principal agents that cause economic losses to sheep production in this region Pathogenic levels of H contortus, Trichostrongylus sp and O columbianum were found respectively during the following periods: summer and autumn, from mid-autumn to the end of winter, and mid-autumn to the end of spring Ostertagia, Cooperia and Dictyocaulus genera were not of epidemiological importance due to the low incidence of infestation The genus Moniezia was similar because it did not cause a homogenous infestation and the worms were expelled spontaneously from the sheep's gut; the epidemiological importance of the genus Nematodirus has still to be determined in this region From the basis of the epidemiological data, a minimum of six anti-helminthic drenches are theoretically needed each year to maintain a sub-clinical level of parasitism in the flocks of Itaqui