Showing papers on "Infestation published in 2001"

Field evaluation of resistance of transgenic rice containing a synthetic cry1Ab gene from Bacillus thuringiensis Berliner to two stem borers.

Abstract: Two transgenic rice (Oryza sativa L.) lines, KMD1 and KMD2 at the R4 generation, transformed with a synthetic cry1Ab gene from Bacillus thuringiensis Berliner, were first evaluated for stem borer resistance in the field during the rice growing season of 1998 in two areas of Zhejiang Province, China. Both KMD1 and KMD2 were highly resistant to the stem borers Chilo suppressalis (Walker) and Scirpophaga incertulas (Walker), and were completely undamaged during the whole rice growing season. In contrast, damage to the plants of the untransformed parental control (Xiushui 11) was in the form of deadhearts or whiteheads. Under natural infestation by the C. suppressalis, the damage to control plants reached a peak of 88.7% of plants and 20.1% of tillers encountered with deadhearts. Under artificial and natural infestation of neonate striped stem borers at the vegetative stage and booting stage, 100% of plants and 25.6% of tillers, 78.9% of plants and 15.6% of productive tillers among artificially infested control plants were observed with the symptom of deadhearts and whiteheads, respectively. Damage to the control plants from artificial infestation by the S. incertulas reached a peak of 97.0% of plants and 22.9% of tillers damaged. The field research indicated that both KMD1 and KMD2 show great potential for protecting rice from attack by these two stem borers.

Ethylene Production and Peroxidase Activity in Aphid-Infested Barley

Abstract: The purpose of this work was to investigate whether ethylene is involved in the oxidative and defensive responses of barley to the aphids Schizaphis graminum (biotype C) and Rhopalophum padi. The effect of aphid infestation on ethylene production was measured in two barley cultivars (Frontera and Aramir) that differ in their susceptibility to aphids. Ethylene evolution was higher in plants infested for 16 hr than in plants infested for 4 hr in both cultivars. Under aphid infestation, the production of ethylene was higher in cv. Frontera than in Aramir, the more aphid susceptible cultivar. Ethylene production also increases with the degree of infestation. Maximum ethylene evolution was detected after 16 hr when plants were infested with 10 or more aphids. Comparing the two species of aphids, Schizaphis graminum induced more ethylene evolution than Rhopalosiphum padi. Infestation with S. graminum increased hydrogen peroxide content and total soluble peroxidase activity in cv. Frontera, with a maximum level of H2O2 observed after 20 min of infestation and the maximum in soluble peroxidase activity after 30 min of infestation. When noninfested barley seedlings from cv. Frontera were exposed to ethylene, an increase in hydrogen peroxide and in total peroxidase activity was detected at levels similar to those of infested plants from cv. Frontera. When noninfested plants were treated with 40 ppm of ethylene, the maximum levels of H2O2 and soluble peroxidase activity were at 10 and 40 min, respectively. Ethylene also increased the activity of both cell-wall-bound peroxidases types (ionically and covalently bound), comparable with infestation. These results suggest that ethylene is involved in the oxidative responses of barley plants induced by infestation.

Managing Striga infestation on maize using organic and inorganic nutrient sources in western Kenya

Abstract: Although the use of foliar biomass (organic residues) of trees and shrubs as a source of nutrients to food crops has been recommended in many countries in sub-Saharan Africa, the effects of biomass quality on Striga (Striga hermonthica) infestation and yields of maize are not known. Organic residues of six species Tithonia diversifolia, Sesbania sesban, Senna spectabilis, Calliandra calothyrsus, Lantana camara and Croton megalocarpus were compared with inorganic nutrients applied through fertilizers at five rates of phosphorus (0, 10, 25, 50 and 150 kg P ha-1) in combination with 120 kg N ha-1, and 150 kg P ha-1 applied alone. The study was conducted in western Kenya over 2 years (four cropping seasons) on a farm severely infested with Striga hermonthica and deficient in P. The fresh foliage of species at 5 t (dry weight) ha-1 and fertilizers were applied every season to the respective plots. Striga infestation was lowest where 120 kg N was applied with or without P. Phosphorus application alone did not i...

A differential interaction study of Bemisia tabaci Q-biotype on commercial tomato varieties with or without the Mi resistance gene, and comparative host responses with the B-biotype

Abstract: Three tomato varieties (Motelle, Ronita, and VFN8) bearing the Mi-1.2 gene providing resistance to nematodes Meloidogyne spp. and to the potato aphid Macrosiphum euphorbiaeThomas, and three varieties not bearing this gene (Moneymaker, Roma, and Rio Fuego), were compared by choice assay for host preference using the Qbiotype of Bemisia tabaci(Gennadius). The most preferred hosts, determined by infestation levels and numbers of feeding adults were Moneymaker, Rio Fuego and Roma, all of which were not carrying the Mi gene. Ronita and Motelle, both of which bore the Mi gene, were the least preferred hosts. In a no-choice assay, B. tabaci females laid a significantly lower number of eggs on the varieties that carried the Mi gene than on those lacking the gene. Differences were more dramatic when plants carrying the Mi gene were pooled together and compared with pooled plants without this gene. Significantly greater values were obtained for the Mi-lacking group for all parameters tested. Comparing these results with those from a previous study on the B-biotype of B. tabaci, Q-biotypes were found to produce higher daily infestation rates on most of the tomato varieties. When results from plants carrying Mi were pooled, they showed lower infestation levels of Q-biotypes than B-biotypes. The Q-biotype infested less Mi-plants and more non-Mi plants than B-biotype. Q-biotype females produced significantly less pupae than the B-biotype females on both groups of plants. These results suggest the existence of an antixenosis and antibiosisbased resistance to the Q-biotype of B. tabaci in Mi-bearing commercial tomato varieties, which is greater than that previously reported for the B-biotype.

Risk factors in habitats of the tick Ixodes ricinus influencing human exposure to Ehrlichia phagocytophila bacteria

Abstract: Ixodes ricinus L. (Acari: Ixodida) were sampled during 1996-99 in southern Scotland, on vegetation using cloth drags, on humans by removal from clothing and on roe deer (Capreolus capreolus L.) by searching legs of culled deer. Developmental microclimate was recorded by automatic recorders and questing microclimate by portable instruments during tick collections. Ticks and deer were examined for infection with Ehrlichia phagocytophila bacteria (Rickettsiales) using microscopy and polymerase chain reaction. This pathogen causes tick-borne fever of sheep in Europe and human granulocytic ehrlichiosis in North America, but in Europe human clinical ehrlichiosis due to E. phagocytophila has not been recorded despite serological evidence of exposure. Among three types of habitat, coniferous woodland was most infested with questing ticks (560 ticks/km of drag; mean numbers collected on long trousers: 24.3 larvae, 13.5 nymphs and 0.8 adult ticks/km walked), deciduous woodland had slightly lower infestation (426 ticks/km drag) and upland sheep pasture had much lower infestation (220 ticks/km drag). Of the three main vegetation types, bracken was least infested (360 ticks/km drag), ericas most (430 ticks/km drag) and grassland had intermediate infestation density (413 ticks/km drag). Questing and developmental microclimates were poor predictors of exposure within these habitats, except lower infestation of pastures was attributed to greater illumination there. Collectors who walked a total of 300 km through all habitats (taking 360 h in all seasons), wearing cotton trousers hanging outside rubber boots, were bitten by only four nymphs and 11 larvae of I. ricinus (but no adult ticks). There was a negative correlation between densities of deer and ticks collected, although presence of deer remains a major indicator of exposure. The proportion of infected ticks was fairly uniform at four sites studied. Overall prevalence of E. phagocytophila in I. ricinus was 3.3% in nymphs (40/1203) but only approximately 1.5% in adults of both sexes (although males do not bite). It was estimated that nymphs of I. ricinus gave 4.4% probability of one infected bite/person/year (for occupational exposure during this research) due to presence in all seasons and habitats, their human biting rate of 0.011 nymphs/h or 0.013 nymphs/km and widespread infection with E. phagocytophila. The frequency distribution of intensity of infection in ticks was approximately normal (mean 98 morulae/nymph infected), thus there is a high risk of receiving a high dose from any one infected tick bite.

Glasshouse studies on the effects of time, temperature and amendment of soil with broccoli plant residues on the infestation of melon plants by Meloidogyne incognita and M. javanica

Abstract: The effects of heating, over a range of temperatures and for increasing periods of time, and of adding finely chopped broccoli leaves to soil infested by Meloidogyne incognita and M. javanica on nematode infestation of melon, were studied in glasshouse experiments. There was a significant interaction between the effects of soil temperature, the period for which this temperature was maintained and broccoli amendment. At the lowest temperature tested (20°C), adding broccoli to the soil had very little effect on nematode infestation or galling of melon. Increasing the temperature of the broccoli-amended soils to 25, 30 or 35°C dramatically reduced infestation and galling compared to that in non-amended soils. Within this range, the effect of broccoli-amendment occurred sooner at higher temperatures. Heating the soil to 40°C for 10 days generally eliminated nematode infestation and root-galling, irrespective of whether broccoli had been added. Fewer egg masses were obtained from melon roots grown in broccoli-amended soils than from those grown in non-amended soils, even when roots exhibited similar degrees of galling. The results suggest that the temperature and time treatments using soil solarisation to control M. incognita or M. javanica could be reduced in soils amended with broccoli residues.

The seasonal abundance of blowflies infesting drying fish in south‐west India

Abstract: Summary 1 Blowfly infestation of sun-drying fish is a major economic problem in many developing countries of Asia, Africa and the Pacific. To consider the ecology of infestation, adult and larval blowfly populations were monitored between 27 October 1997 and 27 April 1999 at a fish landing and drying site, approximately 5 km north of Calicut, in Kerala state on the coast of south-west India. 2 During the 548-day sampling period, a total of 96 953 adult Diptera was collected from 16 sticky targets, placed inside and outside eight fish-storage sheds. Of these, 91 912 (95%) were Chrysomya megacephala, 3719 (4%) were other Calliphoridae and 1322 (1%) were other species, largely Sarcophagidae. 3 The population of C. megacephala showed pronounced seasonal fluctuations in response to climate, particularly relative humidity. Significantly shorter-frequency fluctuations within fish-processing sheds were also evident, the periodicity of which corresponded approximately to C. megacephala generation cycles. Spatial variation in C. megacephala abundance was evident within the site, higher populations occurring closest to the beach and numbers declining with distance inland. 4 The pattern of drying fish infestation by C. megacephala broadly followed changes in the density of adult flies and the seasonal change in weather, with peaks during the monsoon and troughs in the dry hot periods. High relative humidity played a significant but secondary role in increasing infestation. 5 Quantification of the relationship between larval infestation and percentage fish loss suggests that, given the infestation levels observed, between 10% and 60% post-harvest wet weight losses would be expected in the monsoon period, depending on the species of fish landed. 6 The study emphasizes the importance of developing a clear understanding of the basic ecology and spatial and temporal dynamics of an insect pest, prior to the design or implementation of any pest management programme.

An estimate of the economic effects of cattle tick (Boophilus microplus) infestation on Queensland dairy farms

Abstract: Objective To establish the cost to the Queensland dairy industry of cattle tick infestation and its control, excluding the costs incurred from control measures directed specifically at tick fever and morbidity and mortality arising from tick fever. Study design Economic models are described that have been based on empirical data relating to liveweight and milk yield loss, and on a survey of control practices and tick infestation. The first two models were designed to estimate costs of control and losses resulting from tick infestation on a single dairy farm. The third model developed estimates of the cost of tick infestation for each of four regions within the tick-infested area of Queensland. Results The overall cost to the Queensland dairy industry of the cattle tick (excluding the costs associated specifically with tick fever) and based on 1998 management practices, was $4,096,000 per annum. About 49% of this cost was related to the costs of control and 51% to losses in production. Conclusion Cattle tick infestation represents a significant impost on dairy producers in Queensland, and although the actual cost will change as deregulation results in economic changes in the industry, infestations of ticks will continue to be expensive to control.

Induction of Soluble and Cell Wall Peroxidases by Aphid Infestation in Barley

Abstract: Peroxidase enzymes have been found in soluble, ionically bound, and covalently bound forms and have been implicated in several physiological processes in plants. This paper investigates the effect of aphid infestation on soluble and bound-cell wall peroxidase activity and bound-cell wall isoform changes of barley plants. Peroxidase activity was measured in control plants and plants infested with the aphid Schizaphis graminum (Rondani). The activity of soluble peroxidases increased with time of infestation, older plants being more affected than younger ones. The increase in bound-cell wall peroxidase activity as a function of age was higher in infested than in control plants, being higher in ionically bound than in covalently bound peroxidases. When the aphids were removed from plants, the activities of both types of peroxidases decreased to control levels. Isoelectrofocusing analyses of the ionically bound peroxidases showed changes in the isoform pattern. A new isoform was induced by infestation. The activities of all covalently bound isoforms increased after infestation. The physiological implications of these changes are discussed.

Environmental characteristics of the cemeteries of Buenos Aires City (Argentina) and infestation levels of Aedes aegypti (Diptera: Culicidae)

Abstract: Cemeteries with many water-filled containers, flowers, sources of human blood, and shade are favorable urban habitats for the proliferation of Aedes aegypti, a vector of yellow fever and dengue. A total of 22,956 containers was examined in the five cemeteries of the city of Buenos Aires, Argentina. The vector was found in four cemeteries that showed an average infestation level of 5.5% (617 positive out of 11,196 water-filled containers). The four cemeteries positive for Ae. aegypti showed significantly different (p<0.01) infestation levels. Vegetation cover and percentage of infestation were significantly correlated (p<0.01), but neither cemetery area nor number of available containers were significantly related to the proportion of positive vases. Our results suggest that the cemeteries of Buenos Aires represent a gradient of habitat favorableness for this vector species, some of which may act as foci for its proliferation and dispersal.

Environmental factors associated with rodent infestations in Argentine poultry farms.

Abstract: 1. Seasonal variations in rodent infestations were studied at poultry farms in central Argentina as well as the environmental factors associated with rodent infestations at poultry farms. 2. During the summer and winter of 1998 rodent infestation was monitored at 10 poultry farms by means of tracking stations, and 21 environmental variables were selected that a priori could be related with the extent of rodent infestation. 3. There was a higher rodent infestation in winter than in summer. 4. Species detected by rodent sightings at the poultry farms included Akodon azarae, Calomys spp. (C. laucha and possibly C. musculinus) and Mus musculus. 5. In summer, rodent infestation was positively associated with the perimeter of the farm, whereas there was an inverse relationship with the maintenance conditions of the sheds. In winter, rodent infestation was positively associated with the percentage of the borders of the farm covered with vegetation, and with the amount of plant cover, especially the amou...

Seasonal occurrence of Ctenocephalides felis felis and Ctenocephalides canis (Siphonaptera: Pulicidae) infesting dogs and cats in an urban area in Cuernavaca, Mexico.

Abstract: The seasonal occurrence of Ctenocephalides felis felis (Bouche and Ctenocephalides canis (Curtis) infestation on dogs and cats in Cuernavaca City in Mexico, was determined by examining 1,803 dogs and 517 cats at two veterinary clinics during 1995-1997. The overall flea infestation was 30.3 and 30.1% for dogs and cats, respectively. There were no significant differences (P > 0.05) in percentage of infestation among years for both hosts. The infestation was somewhat higher in spring, summer, and autumn than in winter, but no statistical differences was found among seasons (P > 0.05) for both pets. No relationship existed between percentage of flea infestation and temperature or rainfall among seasons. On dogs, 81.1% were infested with only C. felis felis, 16.8% with C. canis, and 2% had both flea species; whereas 92.3% of the cats were infested with C. felis felis and 7.7% with C. felis felis and C. canis. The cat flea was the most prevalent flea species found other than C. canis; no other species were found on the dogs and cats. It appeared that flea life cycle development continued throughout the year.

Tuber damage by potato tuber moth, Phthorimae operculella Zeller (Lepidoptera: Gelechiidae), in the field in eastern Ethiopia

Abstract: The relative rates of tuber damage due to potato tuber moth were assessed in 30 different genotypes of potato grown at Alemaya, eastern Ethiopia. Field infestation in tubers ranged from 6% to 62% and significant differences were observed between genotypes in the degree of damage. Over 42% of the tubers were exposed to tuber moth infestation. Tuber infestation and rotting were found to be positively correlated with exposure. There was an overall increase by 93.2% in infestation and 96.3% in rotting in the exposed tubers over the covered ones. On average, 8.7% of the potato tubers were lost due to field infestation. Based on current potato prices, the average loss was estimated to be 321.75 US$/ha. To reduce field damage and further infestation in storage, therefore, minimization of practices that increase exposure of tubers is strongly recommended.

Monospecific helminth and arthropod infections in an urban population of brown rats from Doha, Qatar.

Abstract: Parasitic infections were studied for the first time in an urban population of brown rats (Rattus norvegicus) from Doha. Only one species of helminth was found, the cestode Hymenolepis diminuta, and one ectoparasite, the flea Xenopsylla astia, from a sample size of 136 rats (52 males and 84 females). The prevalence of H. diminuta was 17.6%, increasing with host age but not in relation to host sex nor season of capture. Host age was a key factor in influencing abundance of infection, although there was a significant three-way interaction with season and host sex arising through heavy infections in juvenile male rats in the summer. The prevalence of X. astia was 45.6%, although both prevalence and abundance of infestations were season and host age dependent. In the winter prevalence and abundance were similar in both host age and sex groups, but in the summer both parameters of infestation were markedly higher among juveniles compared with adults. We found evidence for some association between these two species: H. diminuta was more prevalent among rats with fleas than among those without, although this association was season-, and independently sex- and age-dependent. There were no quantitative interactions and reasons for this are discussed in relation to the foraging and breeding behaviour of the brown rat in Qatar.

Dipteran infestation of loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtle nests in northern Cyprus

Abstract: This paper describes dipteran infestation of loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtle nests in northern Cyprus in 1996 and 1997. Insect larvae were collected from infested nests, reared to adulthood and identified to species. A minimum of 13.4% (1996) and 17.4% (1997) of loggerhead turtle nests and 3.3% and 20.7% of green turtle nests were infested in 1996 and 1997, respectively. Eleven dipteran species were found infesting turtle nests with one species (Sarcotachina aegyptiaca) being dominant. Gross estimates, utilizing the speeds of development for three species of sarcophagid showed that infestation was taking place differentially between the two turtle species. Various aspects of the effect of dipteran infestation on marine turtle nests in northern Cyprus and recommendations for future investigations are discussed.

Host–parasite interactions in natural holes: marsh tits (Parus palustris) and blow flies (Protocalliphora falcozi)

Abstract: Infestation of marsh tit (Parus palustris, Paridae, Passeriformes) broods by bloodsucking larvae of Protocalliphora falcozi Seguy 1928 (Calliphoridae, Diptera) was studied over an 8-year period in a population breeding in natural holes, in the primeval forest (Bialowieza National Park, eastern Poland). Overall 54% of 222 marsh tit nests were parasitized. Prevalence (27–88%) significantly changed across years. This variation did not depend on the timing of the marsh tit breeding season, or winter/spring temperatures. Frequency of infestation did not depend on forest type or hole attributes. Infestation intensity was rather low (median 8, max. 75 flies/nest, 85% of nests with <3 flies/young). Intensity and prevalence were weakly, but positively, correlated. Larger broods contained significantly more blow flies, but per nestling load did not depend on brood size. No effect of infestation on nestlings was recorded – their mortality did not increase, nor was fledging delayed. In response to the presence of blow flies, parents apparently attempted to increase their feeding rate. There was a clear reproductive cost: 60–63% of female and 68–69% of male marsh tits that had none up to eight blow flies, survived to the next spring, but only 34% of females and 44% of males with more than eight flies/brood did so. It is suggested that the small clutch size of marsh tits could have evolved, inter alia, to reduce the fitness costs of ectoparasites.

Interactions of aphid herbivory and nitrogen availability on the total foliar glycoalkaloid content of potato plants.

Abstract: In plant growth room (PGR) and open-air pot (OAP) experiments, potato cvs King Edward and Maris Piper were grown under two nitrogen levels or two different nitrogen release patterns. Plants were subjected to infestation by peach potato aphids Myzus persicae (Homoptera: Aphididae). Total glycoalkaloid (GA) levels were measured in the foliage of both infested and non-infested plants, before, during and after aphid infestation. In the PGR experiment, aphid infestation reduced the amounts of total GAs in both cultivars. This reduction is attributed to the sugar deficiency induced in the plants owing to the dense aphid colonization. Results from the OAP experiment showed a temporal increase of GAs produced by potato cv. King Edward plants subjected to aphid infestation. Elevated amounts of nitrogen in the nutrient solutions (PGR experiment) reduced total GAs, while no differences were observed between manure and fertilizer treated plants (OAP experiment). It is concluded that the source of available nitrogen does not affect foliar GA synthesis in potatoes, and as a consequence, does not affect its endogenous chemical defense against insect herbivory. The case for insect-induced chemical defense mechanisms as triggered by low rates of aphid infestation is discussed.

Spectral characteristics of rice plants infested by brown planthoppers.

Abstract: Spectral characteristics of rice plants at various levels of infestation by the brown planthopper, Nilaparvata lugens (Stal), (Homoptera:Delphacidae), in the early grain-filling stage were measured and analyzed using a spectroradiometer. Plant damage was classified into six scales, i.e., 0 (CK), 1, 3, 5, 7 and 9, based on the scale of infestation displayed on the surfaces of plant parts. Results showed that mean curves of reflectance spectra (350 - 1800 nm) from different scales of insect infestation were clearly differentiated, especially in the region of 737 - 925 nm, where reflectance was in the order of severity. There were significant differences in reflectance among infestations at wavelengths of 755 and 890 nm particularly. Spectral parameters such as the normalized difference vegetation index (NDVI) and cumulative reflectance may also be used to discriminate levels of infestation. Twelve wavelengths from apparent peaks and valleys of individual spectra were selected as characteristic wavelengths making up the spectral signature of each infestation.

Quarantine Security of Bananas at Harvest Maturity Against Mediterranean and Oriental Fruit Flies (Diptera: Tephritidae) in Hawaii

Abstract: Culled bananas (dwarf ‘Brazilian’, ‘Grand Nain’, ‘Valery’, and ‘Williams’) sampled from packing houses on the islands of Hawaii, Kauai, Maui, Molokai, and Oahu identified specific “faults” that were at risk from oriental fruit fly, Bactrocera dorsalis (Hendel), infestation. Faults at risk included bunches with precociously ripened bananas, or bananas with tip rot, fused fingers, or damage that compromised skin integrity to permit fruit fly oviposition into fruit flesh. No Mediterranean fruit fly, Ceratitis capitata (Wiedemann), or melon fly, B. cucurbitae (Coquillett), infestations were found in culled banana samples. Field infestation tests indicated that mature green bananas were not susceptible to fruit fly infestation for up to 1 wk past the scheduled harvest date when attached to the plant or within 24 h after harvest. Recommendations for exporting mature green bananas from Hawaii without risk of fruit fly infestation are provided. The research reported herein resulted in a USDA-APHIS protocol for exporting mature green bananas from Hawaii.

The prevalence of lice infesting students of primary, preparatory and secondary schools in Cairo, Egypt.

Abstract: Human lice (head and body) are among the arthropod-ectoparasites of worldwide distribution. Examining students in primary, preparatory and secondary schools recorded prevalence rates of 21.86%, 30.38% and 12.94% respectively. The overall rate of the lice infestation in the three schools was 384 out of 1772 or 21.67%. The prevalence rate of lice infestation among males and females were 17.02% & 37.8% (primary school), 27.8% & 33.1% (preparatory school), and 12.0% & 13.9% (secondary school). These totaled 17.7% (males) and 30.26% (females). The overall ratio of head to body lice was 18.2:1. Consequently, lice mainly the head louse, are still a public health problem particularly among female students in the primary and preparatory schools. In the secondary school prevalence rate of the lice infestation was low. So human lice is still a community health problem.

Parasites of domestic and wild animals in South Africa. XXXIX. Helminth and arthropod parasites of Angora goats in the southern Karoo.

Abstract: Parasites were collected from 160 Angora goats and kids on the Jansenville Experimental Farm, Eastern Cape Province. Six nematodes were identified to species level and three to generic level. Nematodirus spathiger was the most numerous of the economically important nematodes recovered. It was always present, and fourth stage larvae were collected from untreated goats from August to March, while animals used as tracers also picked up most infection from August to March. Kids born on the farm during October acquired their first nematode infections between 2 and 3 months of age and the intensity of infection increased erratically thereafter to reach a plateau once the kids were 14 months of age. Eight of the nine kids between 3 and 5 months of age and examined between January and March were infected with Moniezia expansa. Five ixodid tick species were collected from the goats of which Rhipicephalus glabroscutatum was the most numerous and prevalent. Its immature stages were present mainly from March to September and adults from July to January. The goats also harboured the biting louse Damalinia limbata and the sucking louse Linognathus africanus. The greatest intensity of infestation with L. africanus occurred on the kids during the first few months of their lives. The larvae of the nasal bot fly, Oestrus ovis were present in kids at 1 month of age, and infestation took place mainly from spring to late summer.

Host selection and performance of the giant willow aphid, Tuberolachnus salignus (Gmelin) - Implications for pest management

Abstract: 1 The recent increase in planting of selected willow clones as energy crops for biomass production has resulted in a need to understand the relationship between commonly grown, clonally propagated genotypes and their pests. 2 For the first time, we present a study of the interactions of six willow clones and a previously unconsidered pest, the giant willow aphid Tuberolachnus salignus. 3 Tuberolachnus salignus alatae displayed no preference between the clones, but there was genetic variation in resistance between the clones; Q83 was the most resistant and led to the lowest reproductive performance in the aphid 4 Maternal effects buffered changes in aphid performance. On four tested willow clones fecundity of first generation aphids on the new host clone was intermediate to that of the second generation and that of the clone used to maintain the aphids in culture. 5 In the field, patterns of aphid infestation were highly variable between years, with the duration of attack being up to four times longer in 1999. In both years there was a significant effect of willow clone on the intensity of infestation. However, whereas Orm had the lowest intensity of infestation in the first year, Dasyclados supported a lower population level than other monitored clones in the second year.

Lacerta bilineata (Reptilia, Lacertidae) as a host of Ixodes ricinus (Acari, Ixodidae) in a protected area of northern Italy.

Abstract: A survey on the importance of Lacerta bilineata as host of Ixodes ricinus was conducted in Northern Italy over a three-year period. A total of 202 western green lizards were captured and a total of 2349 ticks were collected. All ticks were identified as /. ricinus; 53.2% and 46.7% were at the larval and nymphal stages, respectively. Tick number and prevalence were higher in males than in females, especially from April to June during the host breeding period. The level of tick infestation increased with lizard age and size. The number of ticks collected on adult lizards peaked in June and in August. Infestation levels appear to be related to lizard activity patterns and behaviour. Tick number and prevalence also varied in relation to host habitat, infestation being higher in lizards from areas with hard vegetation cover.

Vectorial importance of triatominae bugs (Hemiptera: Reduviidae) in Guaymas, Mexico.

Abstract: The study was conducted in Guaymas city, Sonora, in Northwestern Mexico. Triatomines were collected manually during daytime, within and around houses selected randomly, with one person searching for bugs during one hour per house. Collected bugs were identified and analyzed for Trypanosoma cruzi infection. From a total of 279 collected specimens there were 123 females, 65 males and 91 nymphs (entomological indexes: 63% infestation, 68.4% colonization, 8.5% density and 13.5% stacking). There were 251 (90%) triatominae bugs infected with T. cruzi, one of the highest natural infestation levels recorded in Mexico. The insects collected were identified as Triatoma rubida (91%) and T. recurva (9%). Previous reports for the same locality (1959) indicated the presence of T. rubida in the wild, we found T. rubida within houses, and T. recurva as a peridomestic bug. Unplanned housing developments in originally wild areas may have favored T. cruzi transmitters to migrate from the wild and into human dwellings.

Role of Rusa deer Cervus timorensis russa in the cycle of the cattle tick Boophilus microplus in New Caledonia.

Abstract: Two field experiments were conducted to evaluate the efficiency of Rusa deer in the development of the cattle tick Boophilus microplus in comparison with that of steers in the same pastures and under the same conditions of infestation. No difference was noted between a mixed steer/deer herd and a pure steer or pure deer herd in the infestation pattern of each host, suggesting that attachment to the alternative host is mechanical and not affected by the simultaneous presence of the primary host on the pasture. Deer are capable of producing engorged viable females, with weight and reproductive performances similar to or even better than females fed on steers. For moderate levels (1 million larvae per hectare) and high levels (32 million larvae per hectare) of pasture infestation, tick burdens on steers were not very different (e.g. average 1911 and 2681 ticks per m2 skin, respectively, on day 24). This may be because of saturation of steer skin sites at the moderate larval dose. Deer harboured 2.7–33 times fewer ticks than steers and produce no engorged females at the moderate larval level and 32 times fewer engorged females than steers at the high larval level. Infestation of deer was dose‐dependent with averages of 12 and 399 ticks per m2 skin on day 25 at the moderate and high larval levels, respectively. At a high infestation level of the environment, Rusa deer may contribute, but to a limited extent, to infestation of pastures and, consequently, of cattle. However, their role in sustaining a viable tick population requires further investigation.