Showing papers on "Infestation published in 2007"

Skeletal response of Lophelia pertusa (Scleractinia) to bioeroding sponge infestation visualised with micro-computed tomography

Abstract: The skeleton morphology of the azooxanthellate cold-water coral Lophelia pertusa can be strongly influenced by invasive boring sponges that infest corallites in the still living part of the colony Atypically swollen corallites of live Lophelia pertusa from the Galway Mound (Belgica Carbonate Mound Province, Porcupine Seabight, NE Atlantic), heavily excavated by boring organisms, have been examined with a wide range of non-destructive and destructive methods: micro-computed tomography, macro- and microscopic observations of the outer coral skeleton, longitudinal and transversal thin sections and SEM analyses of coral skeleton casts As a result, three excavating sponge species have been distinguished within the coral skeleton: Alectona millari, Spiroxya heteroclita and Aka infesta Furthermore, four main coral/sponge growth stages have been recognised: (1) cylindrical juvenile corallite/no sponge cavities; (2) flared juvenile corallite/linear sponge cavities (if present); (3) slightly swollen adult corallites/chambered oval sponge cavities; (4) very swollen adult corallites/widespread cavities The inferred correlation between corallite morphology and boring sponge infestation has been detected in micro-computed tomography (micro-CT) images and confirmed in sponge trace casts and peculiar features of coral skeleton microstructure

Small hive beetle, Aethina tumida, populations I: Infestation levels of honeybee colonies, apiaries and regions*

Abstract: The small hive beetle (SHB) is a parasite and scavenger of honeybee colonies. Here we provide the first comprehensive systematic data on colony infestation levels with adult SHB for 226 colonies at 31 apiaries in South Africa, Australia, Florida and Maryland. Inside colonies, SHB distribution was influenced by the presence of bees with more SHB in the brood nest in the absence of bees. SHB distribution among colonies at an apiary was different from a random distribution but colony phenotypes (number of bees, amount of brood or stores) did not influence infestation levels. Apiaries next to large scale honey extraction facilities (honey houses) showed higher infestation levels and regions with more damage had higher SHB population levels. Consequently, methods of reducing SHB populations, such as the removal of dead colonies and the prevention of SHB reproduction in honey houses, seem to be important for pest management.

Response to Recurrent Selection for Resistance to Striga hermonthica (Del.) Benth in a Tropical Maize Population

Abstract: Striga hermonthica (Del.) Benth is an obligate root parasite infecting maize (Zea mays L.) and causing considerable yield losses in Africa. Few studies have been conducted to determine the effectiveness of recurrent selection for improving resistance to S. hermonthica in maize. The objective of this study was to evaluate genetic gain achieved in a composite subjected to six cycles of selection under S. hermonthica infestation. The selection cycles and checks were evaluated with and without S. hermonthica infestation at two locations in Nigeria for 2 yr. Selection for improved performance under S. hermonthica infestation significantly increased grain yield by 24% cycle-1 and ears per plant by 9% cycle-1. At the same time, the gain per cycle was -7% for relative yield loss, -5% for host damage rating, -9% for emerged S. hermonthica plants, -4% for anthesis-silking interval, and -5% for ear aspect. Selection under S. hermonthica infestation was accompanied by a concomitant increase in grain yield and improvement in plant aspect and ear aspect without S. hermonthica infestation. The observed progress in performance under S. hermonthica infestation demonstrates the effectiveness of recurrent selection for increasing polygenetic resistance against the parasite in tropical populations.

Urban infestation by Triatoma dimidiata in the city of Mérida, Yucatán, México.

Abstract: The observation of widespread seasonal infestation by Triatoma dimidiata in rural villages around the city of Merida, Yucatan, Mexico, led us to reconsider the presence of Chagas disease vectors and the risk factors for house infestation in the city itself. Bugs were collected in 150 houses from 30 neighborhoods distributed throughout the city. We observed a widespread infestation by T. dimidiata in the city, with 38% of infested houses and 48% of the collected triatomines testing positive for Trypanosoma cruzi. House infestation by triatomines was greatest during the months of April-June. Infestation risk factors were related with backyard characteristics rather than housing type and quality of housing: houses located in the periphery of the city, with abandoned lots on the sides and large backyards, had a higher risk of being infested, while those with mosquito screens and occasional insecticide spraying in their yards had a lower risk. Several human blood meals were also identified and seropositive patients were distributed through most of the city, confirming the potential for urban transmission of Chagas disease to humans. This study shows that urban Chagas disease should not be neglected and surveillance programs should be implemented to further evaluate the magnitude of the problem.

Prevalence and identification of ixodid tick genera in frontier region peshawar

Abstract: A study to investigate hard tick (Ixodid) infestation and genera identification in 30 different herds in randomly selected 15 villages of Frontier Region Peshawar was carried out during August 2003 through February 2004. Ticks were identified for their genera, in Parasitology Laboratory, Veterinary Research Institute, Peshawar. The effect of month, age, status of body condition, post treatment effect of acaricides, housing and grazing systems on tick infestation was recorded. Out of 1279 farm animals studied, 255 cattle, 97 buffalo, 273 sheep, 544 goat and 110 donkeys were studied for tick infestation. About 13.37 % of the total observed farm animals were found tick infested with highest infestation in cattle (20.4%) followed by sheep (12.8%), goat (12.1%), buffalo (11.3%) and donkey (6.4%). The most commonly prevalent ticks were belonging to genus Boophilus (46.1%) followed by Hyalomma (31.25%), Rhipicephalus (17.93%) and Amblyomma (4.61%). Tick infestation was higher in late summer and lower in winter. The effect of age, status of body condition and post treatment effect of acaricides was found non-significant.

Local and systemic responses induced by aphids in Solanum tuberosum plants

Abstract: The aphids Macrosiphum euphorbiae (Thomas) and Myzus persicae (Sulzer) (Homoptera: Aphididae) are serious pests of potato (Solanum tuberosum L.) (Solanaceae), notably in transmitting several plant viruses. Heterospecific interactions may occur between these two species as they are often seen at the same time on the same potato plant in the field. As aphid infestation is known to induce both local and systemic changes, we conducted experiments to determine the effect of previous infestation on probing behaviour and feeding-related parameters. We used the DC electrical penetration graph technique to characterize the influence of previous infestation by conspecific M. persicae or by heterospecific Ma. euphorbiae on M. persicae feeding behaviour at both local and systemic levels, i.e., on previously infested leaves and on non-previously infested leaves of infested plants, respectively. Conspecific and heterospecific infestation led to similar modification of M. persicae feeding activities. However, the effects of previous infestation occurring at the local level were opposite to those observed at the systemic level. Myzus persicae food acceptance was slightly enhanced on previously infested leaves, whereas it was inhibited on non-infested leaves of infested plants, which indicated an induced resistance mechanism. Our results advance the understanding of the mechanisms involved in aphid-host plant acceptance and colonization processes on potato plants in conspecific and heterospecific situations.

Expression of breeding coloration in European Green Lizards (Lacerta viridis): variation with morphology and tick infestation

Abstract: According to the hypothesis of parasite-mediated sexual selection, for a communication system to work reliably, parasites should reduce the showiness of sexual signals of their host. In this study, we examined whether the expression of breeding coloration in free-ranging adult European Green Lizards (Lacerta viridis (Laurenti, 1768)) is linked with infesta- tion by their common ectoparasite Ixodes ricinus (L., 1758) (Acari: Ixodidae). We found that tick infestation was higher in males than in females. Males showing relatively heavier body for their tail length (predominantly males with regenerated tails) and relatively thinner tail base experienced higher infestation rates. In turn, relatively heavier females for their snout-vent length were less tick infested. Although some components of throat and chest coloration varied significantly with relative tail length, tail-base thickness, body mass, and head size, a measure of male throat and female chest color saturation seemed independent of lizard morphology. After correcting for the effects of morphology on skin coloration and tick load, the saturation of blue throat color in male lizards decreased with increasing level of tick infestation. In contrast, yellow chest color saturation increased with residual tick numbers in females. Considering presumably different signaling functions of male and female lizard coloration, our work suggests that tick infestation might represent a handicap for Green Lizards.

Host community structure and infestation by ixodid ticks: repeatability, dilution effect and ecological specialization

Abstract: Abundance of a species in a location results from the interplay between the intrinsic properties of that species and the extrinsic properties, both biotic and abiotic, of the local habitat. Intrinsic factors promote among-population stability in abundance, whereas extrinsic factors generate variation among populations of a species. We studied (a) repeatability and (b) the effect of abundance and species richness of small mammals on the level of their infestation by larvae and nymphs of Ixodes ricinus (ecological generalist) and Ixodes trianguliceps (ecological specialist). We asked if tick infestation parameters are characteristic (=repeatable) for a particular host species or a particular stage of a particular tick species. We also asked how abundance and diversity of hosts affect the level of tick infestation on a particular host species. We predicted that the dilution effect (decrease in tick infestation levels with an increase of host abundance and/or species richness) will be better expressed in an ecological generalist, I. ricinus, than in an ecological specialist, I. trianguliceps. We found that (a) tick abundance, prevalence and aggregation were generally repeatable within tick species/stage; (b) tick abundance and prevalence, but not the aggregation level, were repeatable within host species; (c) the proportion of variance among samples explained by the differences between tick species and stages (as opposed to within-tick species and stage) was higher than that explained by the differences between host species (as opposed to within host species); and (d) the relationship between tick infestation parameters and host abundance and diversity revealed the dilution effect for I. ricinus but not for I. trianguliceps.

Artificial infestation of Boophilus microplus in beef cattle heifers of four genetic groups

Abstract: Resistance of beef cattle heifers to the cattle tick Boophilus microplus was evaluated by artificial infestation of 66 beef cattle heifers of the following genetic groups: 16 Nelore (NE), 18 Canchim x Nelore (CN), 16 Angus x Nelore (AN) and 16 Simmental x Nelore (SN). The animals, with a mean age of 16.5 months, were maintained with no chemical tick control in a Brachiaria decumbens pasture. Four artificial infestations with 20,000 B. microplus larvae were carried out 14 days apart and from day 18 to day 22 of each infestation the number of engorged female ticks (> 4.5 mm) was counted on the left side of each heifer. Data were analyzed as the percentage of return (PR = percentage of ticks counted relative to the number infested), transformed to (PR)1/4, and as log10 (Cij + 1), in which Cij is the number of ticks in each infestation, using the least squares method with a model that included the effects of genetic group (GG), animal within GG (error a), infestation number (I), GG x I and the residual (error b). Results indicated a significant GG x I interaction, because AN and SN heifers had a higher percentage of return than CN and NE heifers, while CN heifers showed a higher percentage of return than the NE heifers only in infestations 3 and 4. Transformed percentages of return were NE = 0.35 ± 0.06, AN = 0.89 ± 0.06, CN = 0.54 ± 0.05 and SN = 0.85 ± 0.06.

Distribution of dengue vectors in neighborhoods with different urbanization types of Manaus, state of Amazonas, Brazil.

Abstract: Aedes aegypti and Ae. albopictus are vectors of dengue viruses, which cause endemic disease in the city of Manaus, capital of the state of Amazonas, Brazil. More than 53 thousand cases have been registered in this city since the first epidemic in 1998. We evaluated the hypothesis that different ecological conditions result in different patterns of vector infestation in Manaus, by measuring the infestation level in four neighborhoods with different urbanization patterns, during the rainy (April), dry (August), and transitional (November) seasons. Ae. aegypti predominated throughout the study areas and sampling periods, representing 86% of all specimens collected in oviposition traps. High frequencies of houses positive for both species were observed in all studied sites, with Ae. aegypti present in more than 84% of the houses in all seasons. Ae. albopictus, on the other hand, showed more spatial and temporal variation in abundance. We found no association between infestation level and house traits. This study highlights the homogeneity of dengue vector distribution in Manaus.

Pediculus capitis infestation according to sex and social factors in Hamedan-Iran.

Abstract: To determine the intensity of Pediculus capitis infestation (abundance) among school children, children's sex and social factors were analyzed as modifiers of the general prevalence of parasitism. The study included 847 school children (407 girls, 440 boys) between 6 and 12 years, from 12 in public rural primary schools of Hamedan, Province of Hamedan, Iran. Classic prevalence was obtained as the percentage of children with nits and/or lice. The general prevalence was 6.85% (girls: 13.5%; boys: 0.7%, p 0.05). Sex and social factor are important modifiers of P. capitis general prevalence and degree of infestation. The classification of children by intensity of infestation allowed a more precise delimitation of this condition, which is especially important for disease surveillance and application of control measures.

Salt in the Food and Water as a Supportive Therapy for Ichthyophthirius multifiliis Infestation on Silver Catfish, Rhamdia quelen, Fingerlings

Abstract: This study verified the efficacy of common salt (NaCl) in the food and water as a supportive therapy for Ichthyophthirius multifiliis and growth of silver catfish, Rhamdia quelen, fingerlings. After appearance of the first white spots following experimental exposure, indicating infestation by this parasite, fish were transferred to eighteen 40-L polypropylene tanks and kept for 30 d. Experimental diets were prepared with five different levels of salt supplementation: 0.0, 1.2, 2.5, 5.0, and 6.0% for 30 d. In addition, another group of fish were fed a diet without salt supplementation but exposed to 4 g of salt/L of water. Fingerlings were collected at different times for analyses of whole-body Na+, K+, and Cl−. Dietary salt supplementation provoked a transitory increase in whole-body Na+, K+, and Cl− in infested catfish fingerlings, but the best stabilization of these ion levels was observed in specimens exposed to salt in the water. Silver catfish fed a diet containing 1.2% salt showed higher weight and biomass after 30 d compared to those fed with 6% salt. The use of 4 g of salt/L of water improved survival of infested silver catfish, but dietary salt supplementation was ineffective as a therapy for ichthyophthiriasis.

Effects of the Harvest Method on the Infestation of Chestnuts (Castanea sativa) by Insects and Moulds

Abstract: Chestnuts were collected either every 7 days from suspended nets used to intercept the fruits, every 2 days from the ground or every 7 days from the ground. Nuts were visually inspected after collection for the presence of exit holes of the chestnut weevil (Curculio elephas) and the chestnut moth (Cydia splendana), and 20 nuts per sampling and tree were bisected to assess fungal colonization. Apparently healthy nuts were incubated at 24� C and 70–80% relative humidity for 21 days. All nuts were bisected after incubation and examined for the presence of insects and moulds. The harvest method did not have a statistically significant effect on either moulding or insect infestation except on Amphiporthe castanea. This vertically transmitted fungal endophyte was less frequently isolated from fruits collected after 7 days from the ground. The black rot fungus Ciboria batschiana did not occur in chestnuts intercepted in nets, but the difference to chestnuts collected from the ground was statistically not significant. The frequency of nuts colonized by C. batschiana was low in general probably due to the hot and dry summer in 2003. Big, marketable fruits appeared to be less frequently colonized by insects and moulds right after collection. This difference disappeared after incubation except for the chestnut moth. The mother tree had the greatest effect on fungal and insect infestation, indicating the importance of the genetic disposition and/or the phytosanitary situation of each tree. The chestnut weevil preferred chestnuts of the

Plantas infestantes em lavouras de milho safrinha, sob diferentes manejos, no Médio Paranapanema

Abstract: A weed infestation survey was performed in 20 second corn crop areas in 1997 and in 40 areas in 1998 and 1999 after soybean planting in the Medio Paranapanema Region, Sao Paulo. The survey was conducted in the counties of Assis, Campos Novos, Cândido Mota, Cruzalia, Florinea, Maracai, Palmital, Pedrinhas Paulista and Platina. When the corn reached the grain filling stage, the crop weeds were evaluated by zigzag walking through the areas starting from different points to represent the whole area. The crops were classified in three types, according to the system applied: no-tillage, conventional system with disc plowing, and second corn crop in the soybean straw only. Infestation level and occurring weed species were evaluated in each crop. The weed control systems adopted were also considered, according to the herbicides applied. The most important weed species occurring in the areas were: Cenchrus echinatus, Bidens pilosa, Euphorbia heterophylla, Raphanus sativus, Digitaria horizontalis, Commelina benghalensis, Amaranthus sp., Achyrocline satureioides, Sinapis arvensis, Sida sp., Glycine max, Avena strigosa, Eleusina indica and Sorghum halepense. The results showed a strong infestation increase of C. echinatus, which turned out to be the most important weed species in the area evaluated. R. sativus was also important and showed an expressive increase from 1997 to 1999. Weed infestations were higher in the conventional system areas, showing that this system is inferior to the others, concerning weed control. The chemical weed control most used was the mixture of (atrazine+oil) plus 2,4-D, followed by (atrazine+oil) and atrazine alone. No weed control was used in 22% of the crops, which were the most infested. The infestation level varied from year to year for the different weed control systems, depending on climate conditions.

Toward management guidelines for the soybean aphid in Quebec. I. Feeding damage in relationship to seasonality of infestation and incidence of native predators

Abstract: A study was conducted in 2004 and 2005 to test the hypotheses that the severity of damage caused by the soybean aphid, Aphis glycines (Hemiptera: Aphididae), is minimized by the activity of predators and declines with the maturity of soybeans, Glycine max (L.) Merr. (Fabaceae), at the time of infestation. In caged subplots where predators were excluded, aphids attained a high density following experimental infestation of soybeans, resulting in severe reductions of yield, particularly when plants were infested early in the season. A guild of generalist predators consisting predominantly of ladybird beetles colonized plants in uncaged subplots, resulting in a low rate of population growth following infestation of soybeans with aphids and a relatively weak impact on the soybean yield. The soybean yield declined as the density of aphids (number per plant), and the maturity of soybeans at the time of infestation, increased. Our results suggest that A. glycines represents an occasional pest of soybean in Quebec...

Reaction of resistant and susceptible rice genotypes against brown planthopper (Nilaparvata lugens)

Abstract: The study was carried out to assess the reaction of different rice genotypes in response to brown planthopper (BPH)Nilaparvata lugens (Stal.) attack and the possible use of these genotypes in BPH management. The resistant genotypes PTB 33, ADT 45 and ASD 7 and the moderately resistant genotypes CO 43 and KAU 1661 recorded the lowest nymphal preference, fecundity, feeding rate, survival, growth index, population buildup and plant dry weight loss per mg of insect dry weight produced, and more unhatched eggs, longer nymphal development period, days to wilt and higher Functional Plant Loss Index compared with the susceptible genotype TN1. In resistant and moderately resistant genotypes, a greater accumulation of defense enzymes such as peroxidase and polyphenol oxidase in response toN. lugens infestation was recorded one day after infestation, and more pathogenesis-related protein and chitinase activity was noted 3 days after infestation. The activity was sustained for more than a week after infestation compared with the susceptible genotype TN1.

Population structure and growth of polydorid polychaetes that infest cultured abalone Haliotis midae

Abstract: Polydorid polychaetes can infest cultured abalone thereby reducing productivity. In order to effectively control these pests, their reproductive biology must be understood. The population dynamics and reproduction of polydorids infesting abalone Haliotis midae from two farms in South Africa is described using a length-based, age-structured model. Shells were infested mainly by introduced Boccardia proboscidea. Polydora hoplura and Dipolydora capensis were also present but in numbers too few to identify factors influencing infestation. At both farms, B. proboscidea lived for a minimum of 12 months. Growth rate, size at maturity, maximum size, infestation intensity, recruitment, percentage of the population brooding and mortality appear to be affected by abalone feeding regime and water temperature, and these factors need to be considered in controlling infestation. Brooders and recruits were present throughout the year, but increased significantly during mid- to late winter/early spring when water temperat...

Peridomicilary habitat and risk factors for Triatoma infestation in a rural community of the mexican occident

Abstract: An examination of peridomestic area organization and triatomine collection in an endemic village for Chagas disease (Jalisco State) identified the habitat of Triatoma longipennis (dominant species) and the risk factors of peridomestic infestation. In 100 visited peridomestic areas, 369 structures (permanent, temporary, and natural) were submitted to active manual research of triatomines. Storage shelters had a higher infestation of T. longipennis than piles of brick and tile; baked clay material had higher degrees of infestation than others. The secondary species Triatoma barberi shares a wide range of peridomicilary habitats with T. longipennis. Peridomestic area infestation risks (evaluated with multivariate logistic regression analysis) are number of closed storage shelters, number of brick and tile piles, number of houses per peridomestic areas, and distance of peridomicile from natural environment. Because both species present great adaptability to different artificial habitats, strategies of control must involved improving the overall management of peridomestic areas to prevent stable colonization.

Infestation of rural houses by Triatoma infestans in the region of Los Llanos (La Rioja, Argentina)

Abstract: Vectorial transmission of Chagas disease has been strongly reduced in most parts of the Southern Cone countries of South America, except in the Gran Chaco region of Argentina, Bolivia, and Paraguay. Given periodical interruptions of the vector control programmes in the endemic region of the Gran Chaco of Argentina, the vectorial transmission of the disease has been increasing during the last years. From the beginning of 2004, the provincial Ministry of Health of La Rioja, Argentina, started a vector control programme to cover the rural houses of the Los Llanos area in the southwestern area of the Gran Chaco region. This article reports the result of a standardized entomological survey and insecticide application against Chagas disease vectors in the intra and peridomestic structures of the rural houses of Los Llanos. A total of 4062 houses were inspected, of which 46.8% were found to be infested by Triatoma infestans. Infestation by vector species other than T. infestans was less than 0.5%(T. eratyrusiformis and T. platensis). Intradomestic infestation was found in 27.2%, whereas peridomestic infestation was found in 39.3% of the houses. The lowest figure of intradomestic infestation was 6.6% (Department F Varela), and the highest value of intradomestic infestation was 45.1% (Department Independencia). In spite of the demonstrated success of vector control elsewhere, this study shows that the vector populations are susceptible to pyrethroid insecticides in the southern area of the Gran Chaco of Argentina, that there still are regions where rural houses show heavy infestation by T. infestans associated with big peridomestic structures and that the vectorial transmission of the Chagas disease will continue, unless a sustained and well organized vector control effort is installed in the region.

Assessment of susceptibility of olive cultivars to the Bactrocera oleae (Gmelin, 1790) and Camarosporium dalmaticum (Thüm.) Zachos & Tzav.-Klon. attacks in Calabria (Southern Italy).

Abstract: Within the framework of research concerning the application of techniques alternative to chemical pesticides for control of parasites, the CRA Experimental Institute for Olive Growing for many years has been performing a large investigation in order to detect sources of genetic resistance in olive germplasm In the present study we observed the behavior related to the olive fly (Bactrocera oleae) infestation and Camarosporium dalmaticum infection of ten olive cultivars farmed under the same agronomic and climatic conditions in Calabria, Southern Italy The sampling and the data collecting were carried out in three different ripening times The drupe amount of oleuropein and cyanidine was detected by laboratory analyses in order to verify a possible correlation between these molecules and the level of infestation/infection of the above-mentioned parasites The obtained data were submitted to analysis of variance In relation to the fungal infection the results displayed that cvs Tonda nera dolce showed the lowest susceptibility, while the cv Giarraffa turned out to be the most susceptible The less susceptible cultivars to the phytophagous were Tonda nera dolce and Bhardi Tirana Since the less susceptible cultivar to olive fly attacks are the same observed in relation to the susceptibility to olive fruit rot, it is suggested a relation between the olive fly infestation and the fungal infection It suggests the utility to achieve these results both to transfer directly to the farmers' world and to emphasize ecosystem health and biodiversity conservation

Dinâmica populacional de ácaros fitófagos (Acari, Eriophyidae, Tenuipalpidae) em seis clones de seringueira no sul do Estado de Mato Grosso

Abstract: Population dynamics of phytophagous mites (Acari, Eriophyidae, Tenuipalpidae) on six rubber trees clones in southern Mato Grosso State. The population dynamics of Calacarus heveae Feres, 1992, Phyllocoptruta seringueirae Feres, 1998 (Eriophyidae) and Tenuipalpus heveae Baker, 1945 (Tenuipalpidae) was studied on six rubber tree clones (Hevea brasiliensis Muell. Arg.) in south of Mato Grosso State, Brazil, in order to verify the seasonality and the possible differences on the infestation levels of these mites. The samplings were made from March 2004 to March 2005, with an average interval of fourteen days between each sampling. In each sampling, 100 leaflets were taken from each clone crop, and the total number of mites found in both leaf surfaces was registered. The infestation levels of mites differed among the clones. The clone RRIM 600 showed the highest number of T. heveae, while PB 235 and PB 260 had the highest abundance of P. seringueirae and C. heveae, respectively. On the other hand, this latter clone had the smallest infestation of T. heveae and P. seringueirae, while in PB 235 the lowest population of C. heveae. The critical period of mite infestation was observed in the first semester, although, there was variation in the duration of phytophagous occurrence and the infestation peak on six rubber trees clones studied.

Resistance of Apple Cultivars to Dysaphis plantaginea (Hemiptera: Aphididae): Role of Tree Phenology in Infestation Avoidance

Abstract: To test the importance of flowering phenology in damage caused to apple cultivars by rosy apple aphid, Dysaphis plantaginea (Passerini) (Hemiptera: Aphididae), susceptibility of 16 cultivars was compared in greenhouse conditions after infestation with aptera and in the field after natural tree colonization. Flowering phenology was recorded in the field for all the cultivars. In both greenhouse and field trials, there were differences among cultivars with respect to aphid infestation and damage. However, damage in the greenhouse and field was not significantly correlated. Flowering phenology was also different among cultivars. Flowering order among cultivars was significantly negatively correlated with aphid infestation and damage in field, i.e., early leafing cultivars showed higher infestation and damage than late-leafing cultivars. If egg hatching occurs before bud bursting, neonate larvae will suffer a high mortality because they cannot feed on these late cultivars. A later recolonization of these trees is hampered because (1) winged aphids cannot live on apple but only on the secondary host, (2) apterous forms have a limited dispersal capability, and (3) aphid predators progressively increase in the orchard. Therefore, synchronization between egg hatching and bud bursting is of critical importance in the success or failure of infestation.

Environmental characteristics of mountain pine beetle infestation hot spots

Abstract: A combination of favourable temperatures and abundant host trees has resulted in a mountain pine beetle ( Dendroctonus ponderosae Hopkins) epidemic over the majority of the lodgepole pine forests of British Columbia, Canada. Understanding temporal trends in the interactions between mountain pine beetle infestations and landscape characteristics can improve our understanding of beetle biology, inform modelling of future impacts, and support management. In this paper, we demonstrate a practical technique for characterizing spatial interactions between beetles and the environment. The locations with the highest-intensity infestations (hot spots) were identified using point data derived from annual helicopter-based surveys of beetle-infested pine, and a kernel density estimator. By examining the environmental characteristics associated with hot spots through time, an increased understanding of how the mountain pine beetle utilizes resources over large areas is generated. The effect of treatment on the persistence of hot spots is also explored. Results indicate that beetles intensely infest mature trees with a shift to younger trees over time. Hot-spot locations are most commonly associated with stands composed of 30–80% pine and almost always occur at elevations between 800 m and 1000 m. In the early years of an infestation, hot spots are typically found on warmer (south and west) aspects. As well, relative to non-treatment, any type of treatment reduces the persistence of hot spots the following year.

Parasitology and urban livestock farming in nigeria: prevalence of ova in faecal and soil samples and animal ectoparasites in Makurdi.

Abstract: Domestic environmental pollution resulting from urban livestock farming was investigated in Makurdi using parasitological techniques. The test tube flotation technique was used for the parasitological analysis of animal faecal matter and soil samples collected from residential premises. Ectoparasitic fauna of dogs, goats, sheep and cattle cohabiting with humans within the same residential compound were also collected and identified. The hand-picking and body brushing methods were employed to search for ticks, fleas, lice and mites. Of the 150 soil samples examined, 55 (36.7 %) were positive for 1 or more eggs of helminth parasites. There was no significant difference in the distribution of eggs in the soil samples from the 3 areas sampled (c2=0.046, df=2, P>0.05). Ascaris species were the dominant parasite eggs found. Of the 180 faecal samples examined, 107 (59.4 %) were positive for 1 or more eggs of helminth parasites. Chi-square analysis showed no significant difference in the level of infection of different animal faeces sampled (c2=5.74, df=4, P>0.05). Ascaris species were again the dominating helminth parasite eggs found. There was also no significant difference in the prevalence of helminth eggs in the animal faecal samples from the 3 areas sampled (c2=5.99, df=4, P>0.05). A total of 1908 ectoparasites was recovered (ticks: 32.80 %; lice: 22.43 %; fleas: 22.06% and mite: 22.69 %). There was no significant difference in infestation animals between sexes (c2=0.10, df=4, P>0.05). The predominant genus encountered for ticks were Amblyomma, while Linognathus (43.90%), Ctenocephalides (97.38%) and Sarcoptes (58.89 %) were most predominant for lice, fleas and mites respectively. The public health implications of the findings, especially as these relate to the increasing incidence and prevalence of zoonotic infections, are discussed.