Effects of fertilizer and low rates of imidacloprid on Adelges tsugae (Hemiptera: Adelgidae).

Healthy hemlock trees, Tsuga canadensis (L.) Carrière, and hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), populations should favor retention and population growth of adelgid predators such as Laricobius nigrinus Fender (Coleoptera: Derodontidae) and Sasajiscymnus tsugae (Sasaji & McClure) (Coleoptera: Coccinellidae). Eastern hemlock trees between 15 and 38 cm diameter at breast height (dbh) were treated with 0, 10, or 25% of 1.5 g imidacloprid (Merit 75 WP) per 2.5 cm dbh and were either fertilized or not, in a 3 by 2 factorial design. After 2 yr, imidacloprid reduced the numbers of ovisacs and eggs found on trees in a dosage-dependent manner, while enhancing tree growth parameters such as new shoots or needles and the length of new shoots. Fertilized trees had greater adelgid fecundity, which was positively correlated with total foliar N in both winter generations. In February 2009 (27 mo after imidacloprid treatment), higher imidacloprid dosages to unfertilized trees resulted in reduced adelgid fecundity. Concentrations of N, P, and K were higher in the foliage of trees treated with insecticide, whereas foliar aluminum concentrations were consistently lower in trees with higher insecticide dosages. Trees treated with low rates of imidacloprid were healthier than untreated trees, but only trees treated with the 0.1 x dosage had sufficient adelgids to possibly sustain predators over extended periods.

Demographics, nature and treatment of orthopaedic trauma injuries occurring in an agricultural context in the West of Ireland.

BACKGROUND: Farming is a major industry in the West of Ireland. This prospective study examined the age profile, nature and treatment of orthopaedic injuries occurring in agricultural surroundings presenting at the Orthopaedic Unit of Merlin Park Hospital, Galway. METHODS: The cohort consisted of 70 direct or indirect farm employees presenting with orthopaedic injuries caused in an accident occurring on a farm. RESULTS: There were significantly (P < 0.01) more male than female farmers (73 vs. 27%) with a mean age of 63 years (ranging from 13 to 87 years). Average number of out-patient visits related to the injury was 3.6. Injuries involving livestock resulted in the majority of accidents (P < 0.05) with a significant rise in the number of visits with increasing age (P < 0.01) with older patients having more severe injuries. Soft tissue injuries and fractures were commonly encountered. Complex fractures were the slowest injury to heal requiring eight subsequent out-patient visits.

Diathermy versus scalpel incisions for hemiarthroplasty for hip fracture: a randomised prospective trial.

As the age profile of our population expands, we can expect subsequent increase in patients presenting with intracapsular fracture. The onus remains on the surgeon to make all reasonable efforts to find new and innovative means of reducing associated morbidity and mortality of the treatment of these injuries. This challenge is particularly relevant in the elderly and in patients with multiple co-morbidities. In this study, 100 patients were randomly allocated into two groups. One group had dissection to the level of the hip joint under direct diathermy control; the other group had dissection using a scalpel with supplementary electrocautery. Intraoperative total blood loss prior to dissection of the abductors was measured by collecting blood using wound swabs using a local protocol and results were statistically analysed using PROC GLM SAS. We demonstrate a clear advantage in the use of diathermy to create a hip incision showing a significant reduction in wound-related blood loss and a reduction, whilst not statistically significant, in total operative blood loss using diathermy incision. Larger randomised prospective trials are necessary to study the effects of this intervention in a larger patient population so that these end-points can be adequately assessed.

Phenology and demography of Homalodisca coagulata (Hemiptera: Cicadellidae) in southern California citrus and implications for management.

Populations of Homalodisca coagulata (Say) were sampled from citrus orchards in southern California, USA to characterize and quantify seasonal occurrences of nymphs and adults with the goal of identifying management opportunities through well-timed treatments and/or natural enemy releases. Higher densities of H. coagulata in 2001 contributed to a complete seasonal profile that began in early spring with the emergence of first instar nymphs and their progression through five nymphal instars lasting until mid-August. Adult emergence began in mid-June with peak adult densities attained from mid to late August followed by a gradual decline through autumn. A persistent and significant male bias was observed in the adult sex ratio from the time of first emergence through mid-October in oranges; the same trend was present in lemons, but with more variability. Adult densities gradually declined through the winter months into the following spring before rapidly increasing again in June as the 2002 spring generation of nymphs began emerging as adults. The seasonal timing of nymphs and adults in 2002 was nearly identical to that observed the previous year. Phenology data from both years were incorporated into a stochastic, temperature-dependent model that predicts the occurrences of H. coagulata stages through time. Applications of imidacloprid early in the spring generation of nymphs proved very effective at reducing nymphs and sustaining lower densities of adults through summer.

Influence of seasonal nitrogen nutrition fluctuations in orange and lemon trees on population dynamics of the glassy-winged sharpshooter (Homalodisca coagulata).

The glassy-winged sharpshooter (GWSS) is a xylem feeder that develops conspicuous, year-round populations in many citrus-producing regions of California. Field studies were conducted in a combined lemon and orange orchard to determine the influence of changing amino acid concentrations on relative densities of GWSS. Nineteen protein amino acids were detected in xylem fluid of both lemon and orange trees. Although annual profiles of total and essential amino acids were similar for each citrus species, mean concentrations were consistently higher in lemons than in oranges for most of the year, except for one critical period in late winter-early spring when concentrations were higher in oranges. Principal component analysis followed by factor analysis was performed individually on lemon and orange data sets to identify a reduced number of orthogonal factors composed of amino acids having similar seasonal profiles. Four factors were identified for each citrus species that accounted for 85% and 79% of the total variation in the orange and lemon analyses, respectively. These were then examined with respect to shifts in GWSS numbers that occurred asynchronously in lemons and oranges over the annual population cycle. Three distinctive number shifts were identified that included a peak in adult numbers in lemons during August 2001, significantly higher numbers in lemons relative to oranges during midwinter, and finally an increase in oranges of both adults and nymphs during spring 2002. Various groups of amino acids, i.e., factors, displayed peak annual or elevated levels during the intervals when shifts in GWSS numbers were occurring. Soluble protein levels in oranges and lemons did not correspond to shifting GWSS numbers as certain amino acids. However, soluble protein levels were higher in oranges during late winter/early spring when GWSS adults were sexually active. Potential roles of these amino acids and proteins in GWSS host selection are discussed.

An insensitive acetylcholinesterase confers resistance to methomyl in the beet armyworm Spodoptera exigua (Lepidoptera: Noctuidae).

Two forms of acetylcholinesterase were identified in field populations of the beet armyworm, Spodoptera exigua (Hübner), collected from cotton in San Joaquin Valley, CA. Strains (BESS and BKRR) homogeneous for each variant were isolated and their relative susceptibilities to methomyl, chlorpyrifos, and chlorpyrifos-oxon assessed by topical application bioassay. In comparisons with a laboratory susceptible strain (DOW), BKRR and BESS expressed 68-fold and sevenfold resistance, respectively, to the carbamate methomyl. Neither strain was cross-resistant to chlorpyrifos or its oxygen analog (chlorpyrifos-oxon). In biochemical studies, the BKRR AChE enzyme was approximately 30-fold and sixfold more insensitive to methomyl and chlorpyrifos-oxon, respectively, compared with the DOW enzyme. The correlation between the toxicological and biochemical studies provides strong evidence that target-site insensitivity is an important mechanism of resistance to methomyl. The lack of significant cross-resistance to chlorpyrifos suggests that the insensitive AChE in these field populations was selected by methomyl alone and not by the organophosphate.

Biochemical evidence of haplodiploidy in the whitefly Bemisia tabaci.

Polymorphic esterase and acetylcholinesterase alleles in the whitefly Bemisia tabaci were studied using electrophoretic and colorimetric assays. The segregation of these alleles between parental and F1 generations provided unequivocal evidence of haplodiploidy in this pest species. Unmated females, heterozygous at a polymorphic locus, produced a 1:1 ratio of haploid males expressing either of the maternal alleles. Although male offspring were produced by both virgin and mated females, the segregation of alleles showed they were always haploid (hemizygous) for the marker enzymes. Females only arose from fertilized eggs and invariably expressed paternal and maternal alleles.

Biochemical identification of interbreeding between B-type and non B-type strains of the tobacco whitefly Bemisia tabaci.

Polyacrylamide gel electrophoresis and a kinetic microplate assay were used to detect heterozygotes resulting from a cross between B-type and non B-type strains of the whitefly Bemisia tabaci. Both strains were homozygous for different esterase and acetylcholinesterase (AChE) enzymes, and heterozygotes were produced in one of two crosses between B-type females (diploid) and non B-type males (haploid). In reciprocal crosses, however, no female offspring were produced, indicating that fertilization had not occurred. Despite the identification of individuals heterozygous for the esterase and AChE markers, there was clearly a significant degree of reproductive incompatibility between the two strains. The biochemical assays provided a vital component of this study and the advantages of their use are discussed.