Infestation

About: Infestation is a research topic. Over the lifetime, 8308 publications have been published within this topic receiving 82305 citations.

Incidence of Infestation and Larval Success of Emerald Ash Borer (Agrilus planipennis) on White Fringetree (Chionanthus virginicus), Chinese Fringetree (Chionanthus retusus), and Devilwood (Osmanthus americanus)

Abstract: We compared the incidence of infestation by emerald ash borer (EAB) and lilac borer on white fringetree to that of its Asian congener, Chinese fringetree, Chionanthus retusus, and a North American relative, devilwood, Osmanthus americanus. We also conducted laboratory bioassays to determine the suitability of these hosts for EAB larvae. At Spring Grove Cemetery and Arboretum in Cincinnati, Ohio, 9 of 28 white fringetrees examined were infested by EAB. Most of the white fringetrees had lilac borer infestation, and most of the trees infested by EAB also had lilac borer infestation. None of the 11 Chinese fringetrees examined were infested by either EAB or lilac borer. Each of the five devilwood individuals examined was infested by lilac borer, but not EAB. At The Morton Arboretum in Lisle, Illinois, 7 of 16 white fringetrees examined were infested by EAB, while none of the seven Chinese fringetrees examined were infested by either insect. A 40-d bioassay confirmed that white fringetree was an acceptable host, producing fourth-instar larvae that were smaller than those produced on a highly susceptible cultivar of green ash, Fraxinus pennsylvanica. No larvae survived on Chinese fringetree, and neonates were largely incapable of feeding on it. Two larvae survived on devilwood, reaching the second instar and excavating extensive galleries. Future work should be aimed at biotic and abiotic factors influencing the susceptibility of white fringetree, as well as further examination of close relatives for their vulnerability to EAB.

The population dynamics and host utilization of Geomydoecus oregonus, a parasite of Thomomys bottae.

Abstract: Summary. This study treats the population dynamics and host utilization of Geomydoecus oregonus Price and Emerson, a mallophagan parasite of the pocket gopher, Thomomys bottae (Eydous and Gervais). Over 135000 lice were collected from 393 gophers over a period of 20 months. Average infestation on all gophers was 357 lice. Bimonthly mean densities showed an increase in June-July of both years, and these data were statistically different from the rest. Population age structure remained relatively constant in time with 9.3% females, 7.2% males, 47.4% nymphs and 36.1% eggs. Sex-age class separation of the gophers showed juveniles of both sexes to average 86 lice; subadult males averaged 210 lice; adult males averaged 544 lice; subadult and adult females averaged 255 and 296 lice, respectively. Lice were not randomly distributed on the gopher, but were most numerous on the head and anterior dorsal body. Lice eggs were restricted to hairs around the ears and eyes of the host. Over 80% of the animals sampled had eggs restricted to that region. Embryonic development and eelosion of G. oregonus proceeded over a wide range of environmental parameters. Over 80% of the ova tested survived and hatched in conditions between 33 ~ and 37~ and 22 % and 84 % relative humidity. The greatest survival was 98% at 35~ 75% R. H. and in a 3% COs atmosphere. The generation time of G. oregonus was 40 days. Duration of embryogenesis and nymphal stadia approximated 10 days for each. Adult lice lived 30-t- days on gophers. Age frequency mortalities were calculated as 0.02 for eggs, 0.18, 0.24, and 0.06 for nymphal instars and 0.50 for adult lice. This indicates a Type II survivorship curve. There was a direct linear relationship between the number of female lice on a gopher and the number of lice eggs. The average number of eggs per female was four. Using the pivotal frequency for reproduetives, it was possible to calculate R o for the louse at 1.272. Thus, r was equal to 0.24 per generation or 0.006 per day, and the population doubles in 2.8 generations. Speculations regarding population regulation are also included.

Morphological and Physiological Parameters of Soybean Resistance to Agromyzid Beanflies

Abstract: Four soybean varieties which are highly resistant to agromyzid beanflies and two beanfly-susceptible varieties were grown under conditions which simulated those of the fall crop season in Taiwan. Morphological and physiological parameters of the plants with beanfly resistance versus susceptibility were compared. The observed data from the Biotron study were then correlated with those on beanfly infestation in Taiwan. A multiple correlation analysis showed that during the early plant growing stages, the beanfly infestation seems to be influenced especially by the trichome density of the under (abaxial) surface of leaves, leaf area, leaf moisture content, and stem diameter. When a plant is in the V3 stage of growth or older, both the leaf dry weight per cm2 of the second trifoliate leaf and stem moisture content of the internode between the second and third nodes also are positively correlated with the level of beanfly infestation.

Wild birds as hosts of Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae)

Abstract: We evaluated the prevalence, mean intensity and relative density of ticks in 467 wild birds of 67 species (12 families) from forest and cerrado habitats at two protected areas of Minas Gerais, between March and September 1997. Ticks collected (n=177) were identified as larvae and nymphs of Amblyomma cajennense and four other species of Amblyomma. We report for the first time 28 bird species as hosts of the immature stages of A. cajennense, demonstrating the lack of host specificity of the larvae and nymphs. A. cajennense had 15% prevalence on birds, with a mean infestation intensity of 0.37 ticks per host sampled, and 2.5 ticks per infested bird. Prevalence varied in relation to host species, diet and between birds from forests at two successional stages. There were no differences in relation to host forest dependence, participation in mixed flocks of birds, and nest type constructed. A. cajennense is a species of medical and veterinary importance, occurring on domestic animals but is known little of its occurrence on wildlife.