Showing papers on "Infestation published in 1997"

Infestation with pathogen-free nymphs of the tick Ixodes scapularis induces host resistance to transmission of Borrelia burgdorferi by ticks.

Abstract: Female BALB/c mice were infested four times with pathogen-free Ixodes scapularis nymphs prior to infestation with nymphs infected with Borrelia burgdorferi B31. Each infestation was separated by a 14-day tick-free period. Mean weights of fed ticks and percentage reaching repletion did not indicate development of acquired resistance. Only 16.7% of mice repeatedly infested with pathogen-free ticks prior to infected I. scapularis nymph challenge became positive for B. burgdorferi. One hundred percent of control mice infested only with infected ticks were culture positive for B. burgdorferi.

Infestation of mammals by Ixodes ricinus ticks (Acari: Ixodidae) in south-central Sweden

Abstract: Infestation by Ixodes ricinus ticks on rodents, hares and cervids was examined at Bogesund, 10 km north of Stockholm, in south-central Sweden during 1991-1994 and on varying hares (Lepus timidus) at Stora Karlso and Gotska Sandon in the Baltic Sea during 1992-1993. At Bogesund, there were great differences between two consecutive years in the number of I. ricinus larvae infesting bank voles (Clethrionomys glareolus). The seasonal pattern of infestation by I. ricinus larvae and nymphs on bank voles was unimodal in 1991, with peaks in June-July and bimodal in 1992, with peaks in June and August. Male bank voles, compared to females and older voles, compared to young voles, harboured greater numbers of I. ricinus ticks. Apodemus mice, compared to bank voles, harboured greater numbers of I. ricinus ticks. Ixodes ricinus larvae engorged on Apodemus mice were heavier than larvae engorged on bank voles and resulted in larger nymphs. However, there was no difference in the proportions of viable nymphs resulting from larvae engorged on mice or voles. The ranges in the numbers of I. ricinus ticks infesting individual hosts were 1-451 for rodents, 16-2374 for hares and 428-2072 for roe deer (Capreolus capreolus). These ranges of tick numbers are estimated to represent potential blood losses from individual hosts of approximately 0.2-65% for rodents, 0.2-13% for hares and 0.3-9.0% for roe deer. Within the populations of all host species examined, the distributions of all stages of I. ricinus were clumped, with most host individuals harbouring few ticks and only a few individuals harbouring many ticks. The data suggest that, even though a small proportion of tick hosts may be severely affected, the direct effects of feeding by I. ricinus are unlikely to play an important role on mammal population dynamics.

Fall armyworm (Lepidoptera: Noctuidae) and Diatraea lineolata (Lepidoptera: Pyralidae) : Impact of larval population level and temporal occurrence on maize yield in Nicaragua

Abstract: Four experiments were conducted in Nicaragua over a 3-yr period to determine the effect of whorl-stage infestations of Spodoptera frugiperda (J. E. Smith) and Diatraea lineolata (Walker) on maize grain yields. The experiments separated the effects of period of infestation from level of infestation. Results from all experiments demonstrated that maize is more tolerant of lepidopteran infestation during early growth stages than at later stages. Infestation during mid-through late whorl caused yield losses of 15-73% when 55-100% of the plants were infested with S. frugiperda. D. lineolata infestations were highly correlated with S. frugiperda. D. lineolata infestations were highly correlated with S. frugiperda infestation. Economic injury levels ranged from 23 to 63% of the plants infested with S. frugiperda and D. lineolata over a range of potential yields, using mean yield reduction from the 4 experiments, and an average 75% insecticide effectiveness.

The coevolutionary potential of a 'generalist' parasite, the hen flea Ceratophyllus gallinae.

Abstract: Hosts exert selection pressures on their parasites and it is often assumed that host-parasite coevolution with each host is less intense in a generalist parasite than for a parasite with a narrow host range. Selection pressure on the parasite, however, is rather determined by host specificity, i.e. the relative importance of each host, than simply by the range of hosts. The determination of host specificity requires an assessment of the prevalence and intensity of parasite infestation within each host's nests, as well as the local abundance of each host species. Since the hen flea, Ceratophyllus gallinae, is a rather generalist parasite of birds it could be concluded that there has been weak coevolution with each of its hosts. By reviewing the literature on the prevalence and intensity of hen flea infestations in bird nests we estimated the number of individuals produced in the nest of each host species. The comparative analysis shows (1) that the prevalence of infestation is highest in hole-nesting avian families, (2) that prevalence and intensity of infestation among bird families are highly correlated, and (3) that hole-nesting Paridae have the highest intensities of infestation and harbour the majority of the flea population. These results underline the fleas' potential for coevolution with Paridae despite their extensive host range.

Open-ocean infestation by salmon lice (Lepeophtheirus salmonis): comparison of wild and escaped farmed Atlantic salmon (Salmo salar L.)

Abstract: Salmon lice (Lepeophtheirus sabnonis) infestation was investigated in 128 salmon (S&IO s&r L.) caught on floating long-lines in the Norwegian Sea during NovemberMarch 199331995. Overall prevalence was 99.2% and abundance 29.5 lice per salmon. Most lice were adults (90%) and 72% of these were ovigerous females. These adult lice were estimated to be at least 3 months old based on prevailing sea-surface temperatures at the sampling site: 7°C in November and 3°C in March. The prevalence and abundance of lice on one sea winter (1SW) salmon were significantly higher on escaped farmed fish than on wild salmon. However, no difference in abundance was observed between 2SW farmed and wild salmon. The average number of lice per surface area of fish (density) was significantly higher in 2SW wild salmon than in 1SW wild salmon, indicating an accumulation of lice on the salmon in the oceanic phase. No differences in density were observed between 1SW and 2SW farmed salmon. The prevalence of Cakgus elongutus was low (5.5%), with an abundance of 0.9 lice per salmon. 0 1997 International Council for the Exploration of the Sea

Effects of chickens on the prevalence of infestation and population density of Triatoma infestans in rural houses of north-west Argentina

Abstract: Effects of the presence of chickens on population density of the bug Triatoma infestans, principal vector of Chagas disease, were investigated by standardized sampling (indoors and peridomestically) from sixty-eight houses of three rural communities in north-west Argentina, during March 1992. The domiciliary density of T. infestans increased linearly with the percentage of bugs that fed on chickens, as identified by agar double-diffusion tests. Bug density was significantly higher in houses where hens usually nested indoors than in those where they did not, as determined by concurrent direct observations and interviews of householders. Multiple linear regression analysis of domiciliary bug density on (a) the total number of people, dogs and cats per house; (b) the percentage of domiciliary bugs that fed on chickens, or (c) the indoor-brooding habit of hens, showed the two variables (b, c) related to chickens as significant predictors in each regression model. Inclusion both variables representing chickens increased the fit significantly. Addition of other potentially confounding factors (domestic insecticide use, type of roof and walls of house) did not affect the significant variables retained in the best-fitting regression model. Peridomestic infestation was positively associated with the household number of fowls. Chickens were the main bloodmeal source of peridomestic T.infestans populations. Human-fed bugs were detected in peridomestic sites of sixteen houses, indicating active dispersal of adults and large nymphal instars from bedroom areas. Exclusion of hens from domiciliary areas and promotion of chicken sheds, of an appropriate design that would not harbour bug populations, should limit the triatomine population growth rate and reduce the risk of infestation.

Nitrogen Effects on Striga hermonthica Infestation, Grain Yield, and Agronomic Traits of Tolerant and Susceptible Maize Hybrids

Abstract: A phytoparasite, Striga hennonthica (Del.) Benth., infests millions of hectares of cultivated fields of cereal crops in sub-Saharan Africa. Yield losses are often 70 but can be as high as 100% and farmers often abandon infested fields and move to new areas. The objectives of this study were to investigate the effects of nitrogen on S. hennonthica infestation and the subsequent grain yield and agronomic traits of tolerant and susceptible maize hybrids (Zea mays L.). Two tolerant and two susceptible hybrids were grown under six levels of N (0-150 kg ha -1 ), with and without Striga seed infestation. The trials were conducted for 3 yr at Mokwa, Nigeria. Each plant was infested with approximately 3000 germinable Striga seeds, and the density of Striga that emerged, Striga damage on the host plant, plant height, stalk lodging, and grain yield were measured. Striga infestation (emergence and host damage), maize grain yield, and plant height were significantly affected by N rates. Two tolerant hybrids showed significantly lower Striga emergence and host plant damage symptoms than the susceptible hybrids (P < 0.001). Interactions between infested and uninfested plots and hybrid (tolerant vs. susceptible) for grain yields and stalk lodging were significant (P < 0.001). Striga infestation reduced grain yields of two susceptible hybrids by 49%, and of two tolerant hybrids by 24%. The two tolerant hybrids produced on average 87% greater grain yields than the two susceptible hybrids under low N rates (0-60 kg ha -1 ) and 51% greater yields under high N (90-150 kg ha -1 ). Among the plant traits measured, Striga damage score had the highest correlation with grain yield (r = -0.60**).

Characteristics of Hydroxamic Acid Induction in Wheat Triggered by Aphid Infestation

Abstract: Hydroxamic acids (Hx) are natural products of Gramineae that are associated with cereal resistance to pests. We aimed at characterizing the induction of Hx accumulation in seedlings of wheat,Triticum aestivum, by short-term infestation of the cereal aphid,Rhopalosiphum padi. A load of 25 aphids increased significantly the Hx levels in the infested primary leaf in comparison with control levels. Lower loads did not increase Hx concentration. Aphid infestation lasting 16 hr did not elicit induction of Hx, even after a time-lag of 32 hr to allow the expression of any induced response. Forty-eight hours was the minimum duration of aphid infestation required to trigger Hx induction. The age of the infested tissue (the primary leaf) did not affect induction. Similar increases of Hx were found in unfolding, expanding, and totally expanded primary leaves. It was determined that the regime of nutrient supply (N-intensive nutritive solutions at low and high concentration) to wheat seedlings had no effect on the magnitude of the aphid-induced Hx (N-based secondary metabolites). Results obtained are discussed in the framework of general theories of plant defense allocation.

Variations in parasitic caligid infestations on farmed salmonids and implications for their management

Abstract: In order to evaluate the performance of various sea lice management strategies, data sets from a number of salmon farm sites on the west coast of Ireland were examined. These data sets were collected as part of the ongoingNational Sea Lice Monitoring Programme in Ireland. Temporal and geographic variations in infestations of Lepeophtheirus salmonis and Caligus elongatus are described from two species of farmedsalmonids, Salmo salar L. and Oncorhynchus mykiss Walbaum. Patterns of lice transmission, both within and between fish populations, are discussed and environmental and biotic influences considered. Clear differences in infestation parameters, which persist over a number of seasons, are identified between sites. Where infestation parameters are observed to change over successive seasons, these are linked to changing husbandry practices.

Body size and habitat as determinants of tick infestations of wild ungulates in South Africa

Abstract: The purpose of the present work was to test the hypothesis that the intensity of tick infestation on South African wild ungulates is proportional to surface area of the host (body weight0.67) and to assess the role of habitat preference on the intensity of infestations. The results support previous suggestions that larger ungulates are more important hosts for adult ticks, however, the intensity of infestation of nymphs and larvae is proportional to the surface area of the host. Grazers had a lower intensity of infestation than browsers and intermediate feeders. The difference was most pronounced in the 30 to 150 kg weight range within which the grazers were predominantly short-grass grazers which utilize habitat less suitable for ticks. These patterns appeared to be consistent within the three major collection areas, Kruger National Park, KwaZulu-Natal and Mountain Zebra National Park.

Maize response to corn leafhopper (Homoptera: Cicadellidae) infestation and achaparramiento disease

Abstract: To determine the effect that the timing of infestation of Dalbulus maidis (DeLong & Wolcott), a vector of 3 maize pathogens, known collectively as “achaparramiento,” has on stunt symptoms and maize yield, we conducted a field trial in the Sebaco Valley of Central Nicaragua. Achaparramiento has caused severe yield losses in maize throughout Central America. Six periods of D. maidis infestation were created using exclusion cages of finemesh screening. The treatments were natural infestations of D. maidis during 0-10, 10-20, 20-30, 30-40, 0-40 d after plant emergence, and no D. maidis infestation. The treatments were repeated on 3 planting dates. During the season, population densities of D. maidis varied from 4 to 8 per plant for the 1st planting date, from 1 to 3 per plant in the 2nd planting date, and from 2 to 8 per plant in the 3rd date. Planting date had a significant effect on plant height, the number of ears, and the yield per plant, but not on disease symptoms or the length of the ears. The timing and duration of D. maidis infestation affected disease symptoms, plant height, and yield: earlier periods of D. maidis infestation produced more pronounced disease symptoms, shorter plants, and lower yields than treatments with late D. maidis infestation. Plant infested 10-20 d after plant emergence had significantly lower yields than plants infested 30-40 d after plant emergence, and plants infested 30-40 d after plant emergence did not have Significantly different yields from plants that were not infested. The yield reduction was caused by smaller ears, not a reduction in the number of ears. The results demonstrate that a management program for reducing the effects of maize stunting diseases caused by the 3 pathogens should be focused on tactics that reduce D. maidis levels from seedling through midwhorl stage of maize growth.

Suppression Mechanisms of Meloidogyne arenaria Race 1 by Pasteuria penetrans.

Abstract: The biological control of Meloidogyne arenaria on peanut (Arachis hypogaea) by Pasteuria penetrans was evaluated using a six x six factorial experiment in field microplots over 2 years. The main factors were six inoculum levels of second-stage juveniles (J2) of M. arenaria race 1 (0, 40, 200, 1,000, 5,000, and 25,000 J2/microplot, except that the highest level was 20,000 J2/microplot in 1995) and six infestation levels of P. penetrans as percentages of J2 with endospores attached (0, 20, 40, 60, 80, and 100%). The results were similar in 1994 and 1995. Numbers of eggs per root system, J2 per 100 cm³ soil at harvest, root galls, and pod galls increased with increasing nematode inoculum levels and decreased with increasing P. penetrans infestation levels (P = 0.05), except that there was no effect of P. penetrans infestation levels on J2 per 100 cm³ soil in 1994 (P 0.05). There were no statistical interaction effects between the inoculum levels of J2 and the infestation levels of P. penetrans (P 0.05). When the infestation level was increased by 10%, the number of eggs per root system, root galls, and pod galls decreased 7.8% to 9.4%, 7.0% to 8.5%, and 8.0% to 8.7% in 1994 and 1995, respectively, whereas J2 per 100 cm³ soil decreased 8.8% in 1995 (P = 0.05). The initial infestation level of P. penetrans contributed 81% to 95% of the total suppression of pod galls, whereas the infection of J2 of the subsequent generations contributed only 5% to 19% suppression of pod galls. The major suppressive mechanism of M. arenaria race 1 by P. penetrans on peanut is the initial endospore infestation of J2 at planting. Key words: Arachis hypogaea, bacterium, biological control, endospore, Meloidogyne arenaria, Pasteuria penetrans, peanut, root-knot nematode.

Some factors affecting infestation of white-tailed deer by blacklegged ticks and winter ticks (Acari:Ixodidae) in southeastern Missouri.

Abstract: A total of 5,669 ticks of 4 species was collected from 515 hunter killed, whitetailed deer, Odocoileus virginianus (Zimmerman), in southeastern Missouri from 1993 through 1995. The American dog tick, Dermacentor variabilis (Say) (4 adults), the lone star tick, Amblyomma americanum (L.) (57 adults, 2 nymphs), the blacklegged tick, Ixodes scapularis (Say) (3,120 adults), and the winter tick, Dermacentor albipictus (Packard) (2,059 adults, 436 nymphs, 1 larva) were collected. Patterns of adult D. albipictus and I. scapularies infesting deer were analyzed with respect to upland versus lowland habitat, county, and host sex. Prevalence and intensity of infestation by D. albipictus were higher on bucks than does, and a higher infestation prevalence was recorded for this tick on deer from upland than from lowland habitats. Mean intensities for D. albipictus were not significantly different between counties. Prevalence and mean intensity of infestation for I. scapularis were significantly higher on deer from uplands than lowlands and on bucks than does; mean intensities also differed between counties for this tick. Because adjacent populations, as well as the sex of the host, can differ in infestation rates, differences between local populations of I. scapularis should be recognized to optimize tick surveys and population models.

Effect of plant density on grain yield, root–length density and Orobanche crenata infestation in two faba bean genotypes

Abstract: Summary The effect of host plant cultivar and sowing density on Orobanche crenata Forsk. L. infestation in Vicia faba was studied in a field experiment in north–west Syria. Two faba bean genotypes. ILB 1814 (Syrian Local Large) and 402/29/84 (new breeding line from Egypt), were planted at four sowing densities. Whereas ILB 1814 was severely affected by O. crenata, 402/29/84 proved to be highly resistant. Sowing density did not have a significant effect on O. crenata dry weight in either genotype. However, the number of O. crenata attachments in ILB 1814 was positively correlated with plant density. The resistance of faba bean genotype 402/29/84 to O. crenata is due to: (a) less plant vigour and root–length density; (b) necrosis of host cells preventing O. crenata attack either before or just after penetration into the host root, or developing a barrier in the host root after the formation of a small tubercle: (c) early flowering and pod setting.

Striga hermonthica seed inoculum rate effects on maize hybrid tolerance and susceptibility expression

Abstract: A parasitic plant, Striga hermonthica (Del.) Berth.,infests millions of hectares of arable land in sub-Saharan Africa, and it threatens production of major cereal crops including maize (Zea mays L). Erratic natural infestation is considered a major constraint to assess host plant resistance to the parasite. The objective of this study was to evaluate the effects of different S. hermonthica seed inoculum rates on a tolerant and a susceptible maize genotype. Individual maize plants of the tolerant (8322-13) and the susceptible maize hybrid (8338-1) were inoculated with six rates of germinable Striga seeds: 750, 1500, 2250, 3000, 3750, and 4500. Uninfested plots served as the control. The experiment was conducted at two locations, Mokwa (two seasons) and Abuja (one season), in Nigeria. Increasing Striga inoculum level increased Striga emergence and the amount of damage to the host plant, plant height, and grain yield of the host crop. The tolerant hybrid showed less host plant damage (P < 0.01) and that fewer S. hermonthica plants emerged (P < 0.05) than the susceptible hybrid. Among the four traits studied, host plant damage score was most correlated with grain yield (r = -0.65**). Average grain yield of the tolerant hybrid, 8322-13, was 97% higher than that of the susceptible hybrid, 8338-1, across the six inoculum rates. The tolerant hybrid produced similar grain yields under all levels of the inoculum; the yield reductions ranged from 27% (2250 seeds) to 35% (4500 seeds), while the yield reduction of the susceptible hybrid ranged from 43% (750 seeds) to 74% (3750 seeds). Based on the results of this study, we conclude that host plant tolerance is the key element for stabilizing crop yield under S. hermonthica infestation.

Scale insects consistently affect roots more than shoots: the impact of infestation size on growth of eucalypt seedlings

Abstract: 1 Different infestation levels of the phloem-feeding scale insect, Eriococcus coriaceus Maskell (Hemiptera: Eriococcidae), consistently reduced root growth more than shoot growth in seedlings of Eucalyptus blakelyi Maiden (Myrtaceae). 2 Low levels of scale insect infestation significantly decreased root and lignotuber biomass but not shoot biomass. High levels of infestation, however, adversely affected all plant parts. Root and lignotuber biomass declined linearly, while the responses of stem and leaf biomass were nonlinear, with respect to increasing total insect load. 3 Plant responses to scale insect infestations may be explained by considering sapsucking insects as additional sinks that compete against plant sinks and both redirect and drain resources from the plant. 4 Scale insect populations exhibited strong density dependent effects, suggesting they were severely depleting resources within their hosts. Extensive shoot death at high levels of infestation may have contributed to insect population decline by causing scale insects to die prematurely or by reducing the availability of suitable feeding sites.

Estudo sobre triatomíneos e reservatórios silvestres de Trypanosoma cruzi no estado do Paraná, Sul do Brasil. Resultados preliminares

Abstract: In the rural area of five municipalities of the Northeast of the State of Parana, Brazil, 154 adults or nymphs of Triatoma sordida and 2 Panstrongylus megistus were captured in 21 (41.2%) of 51 dwellings at the peridomestic sites. Trypanosoma cruzi-like organisms were found in 58 out of the 135 (43.0%) triatomids. Moreover, it was also found in the blood of 4/7 opossum (Didelphis sp). The triatomine infestation was more prevalent in the peridomicile than inside house. The forsaken wooden house presented the highest level of infestation (53.8%). Although the rural area of the Northeast of the State of Parana is considered under epidemiologic surveillance it still presents a high level of peridomestic infestation by triatomids highly infected with T. cruzi-like organisms.

Resistência e suscetibilidade de bovinos leiteiros mestiços ao carrapato boophilus microplus

Abstract: Counts of the cattle tick Boophilus microplus were made on a crossbred dairy herd raised at the “Estacao Experimental de Zootecnia de Colina”, north of Sao Paulo State, Brazil, in the middle of each season, during two years. The objective of the study was to assess for some genetic and environmental effects that might be affecting tick resistance on the herd. Counts of female ticks more than 4.5 mm in length were analysed by least squares method (n = 4.218), using counts (x) transformed to In 2 (x + 1). The results showed significance (P < 0.01) for the effects of sire, season, sex, age, pasture and grass species. Natural infestation levels increased in summer and decreased in winter, with a peak in fall. Four strategic dippings, realized at 21 days interval just after the spring count, reduced tick infestation in the following season. Males were more susceptible than females. Unweaned calves aged 2-3 months were highly resistant to the tick, while those aged 8 to 12 months and more than 4 years old were more susceptible. Animals grazing on newly-formed or spelling pastures had lower tick infestation than those on continuous grazing pastures. Animals grazing on pastures of “coloniao” grass (Panicum maximum Jacq cv. Coloniao) had the lowest tick counts. Overall means of tick counts and heritability were 10 and 0.089 ±0.030, respectively.

The influence of companion crops in the control of insect pests of cowpea in intercropping systems

Abstract: The influence of companion crops on pest infestation of cowpea [Vigna unguiculata (L.) Walp.] was investigated using five crops arranged in a randomized complete block design. Maize, pepper, and cassava plants significantly (P < 0.05) reduced the population of cowpea flower thrips, Megalurothrips sjostedti (Trybom), on the cowpea intercrop. The infestation of cowpea by the cowpea aphid, Aphis craccivora (Koch), was also significantly reduced by the presence of pepper (P < 0.05) while maize, cassava, and pigeon pea intercrops reduced the incidence of blister beetles, Mylabris sp. on cowpea. However, none of the companion crops significantly reduced cowpea damage by the mung moth, Maruca testulalis (Geyer), African pea moth, Cydia ptychora (Meyr), and the hemipteran complex which constitute the major pests of the cowpea crop.

Ixodes ricinus (Acari: Ixodidae) infestation on roe deer (Capreolus capreolus) in Trentino, Italian Alps.

Abstract: The most important tick-deer system potentially supporting the epidemiology of Lyme disease in the Italian Alps is that regarding Ixodes ricinus (L.) and roe deer (Capreolus capreolus L.). In this study, the pattern of tick infestation on 562 male roe deer harvested in September 1994 in 56 game districts of Trentino, Northern Italy, was assessed. The prevalence and density of infestation by I. ricinus were analyzed by a model based on classification and regression trees (CART), using both discrete and continuous variables concerning environmental and host parameters. The model discriminated attitude and host density as the 2 variables having the greatest effect on the prevalence and density of infestation of deer; the levels of infestation were higher at an altitude below 1125 m or at roe deer densities over 8.5 head per 100 ha. The density of tick infestation tended to be higher in older roe deer.

Parasites of mammals on the Sevilleta National Wildlife Refuge, Socorro, New Mexico: Cuterebra austeni and C. neomexicana (Diptera:Oestridae) from Neotoma and Peromyscus (Rodentia:Muridae), 1991-1994.

Abstract: In total, 6,486 rodents representing 3 families (Muridae, Heteromyidae, and Sciuridae) and 24 species were trapped May through August of 1991 through 1994. Of these, only the white-throated woodrat, Neotoma albigula Hartley; pinon mouse, Peromyscus truei Shufeldt; and white-footed mouse, P. leucopus Rafinesque, were infested with Cuterebra Clark larvae. Of the 594 N. albigula that were captured, 103 (17.3%) were infested with 139 Cuterebra larvae with all infestations occurring in the throat region. N. albigula infestations were observed in 4 of 5 habitats sampled. The highest prevalence of infestation occurred during May–June (27.2%) versus July–August (9.1%) and in males (25.2%) versus females (18.3%). Prevalence of infestation was not significantly different between animals from the mark-release webs versus removal webs or adults versus juveniles. Also, there was no correlation between relative density of N. albigida and prevalence of infestation. Fifteen adults were reared from puparia and identified as C. austeni Sabrosky. Of 716 P. truei captured, 22 (3.1%) were infested with a total of 25 Cuterebra larvae with all infestations occurring in the scapular region. Although P. truei were captured in all 5 habitats, they were only infested in the pinon-juniper habitat; the highest prevalence of infestation occurred during July–August (10.9%) versus May–June (3.3%). Prevalence of infestation was not significantly different between animals from mark-release webs versus removal webs, males versus females, or adults versus juveniles. As in the N. albigula, there was no correlation between relative density of P. truei and prevalence of infestation. The adult reared from a puparium was identified as C. neomexicana Sabrosky. Of the 310 P. leucopus captured, only 3 (1%) were infested with Cuterebra larvae.

Spatial distribution and seasonality of ticks (Acarina: Ixodidae) in a protected area in the northern Apennines.

Abstract: Infestation of small rodents by ixodid ticks and frequency of host-seeking ticks collected by dragging were studied at Orecchiella Natural Park (Northern Apennines) in 1994 and 1995. Levels of infestation of Apodemus spp. by immature Dermacentor marginatus were higher in beech wood (5.1 larvae and 1.3 nymphs per mouse) than in oak-chestnut wood and in coniferous wood. Larval D. marginatus peaked in mid summer, whereas nymphs peaked in late summer. Host-seeking Haemaphysalis punctata were mostly found on south-facing limestone rocks with scarce vegetation (7.8 larvae/km dragging). Conversely, D. marginatus larvae were most frequent in wooded areas (3.2 larvae/km dragging). Ixodes ricinus was rare in the Park, and Borrelia burgdorferi was not isolated from ear punches collected from 122 small rodents.