Comparative studies on acylurea insect growth regulators and neuroactive insecticides for the control of the armyworm Spodoptera exempta walk

Leaf-dip bioassays with commercial pesticide formulations were used throughout this study. Third-instar larvae of Spodoptera littoralis were bioassayed for comparative purposes. The end-point mortality against the third-instar larvae (L3) of two Spodoptera exempta populations (Bangor and Gent) and a S. littoralis population (NRI) was found to occur at 72 h and 120 h for neuroactive compounds (carbamate, organophosphate and pyrethroid insecticides) and acylureas respectively. Overall, the acylureas were found to be more toxic (up to 240-fold at the LC₅₀ level) than the most active of the neuroactive compounds tested, the pyrethroids. This difference was greatest against S. littoralis, which was markedly less sensitive to the latter compounds. The Gent population of S. exempta was also found to be significantly less sensitive (7-folt at LC₅₀) to the pyrethroid, lambda-cyhalothrin, than the Bangor strain. Two of the most toxic neuroactive and non-neuroactive compounds, the pyrethroid, cypermethrin and the acylurea, teflubenzuron were chosen for further studies with S. exempta (Gent) and S. littoralis. Relatively little difference in the toxicity of teflubenzuron was observed against different larval instars (L2, L3 and L4) of S. exempta when compared with cypermethrin. Choice-chamber-experiments on feeding behaviour showed that when L3 larvae of either species were exposed to both treated and untreated leaves. teflubenzuron had no significant effect on larval distribution, the percentage of each leaf disc consumed or larval weight gain when compared with untreated controls. In contrast, a marked dose-dependent repellent response to cypermethrin-treated leaves was shown by S. littralis after 6 h. together with corresponding reductions in the percentage of the treated leaf consumed and in larval weight gain. Similarly, when L3 S. exempta were exposed only to pesticidetreated leaves, cypermethrin significantly reduced premoult larval weight gain, whereas tefiubenzuron had no premoult effect. However, following exposure of L3 S. exempta and S. littoralis to teflubenzuron for 48 h prior to moulting, L4 which survived the moult showed reduced weight gain compared with controls, the reduction being more pronounced on maize than on artificial diet. This antifeedant effect increased in proportion to the concentration of teflubenzuron originally administered. The effect of exposure time to teflubenzuron was examined by placing L3 S. exempta and S. littoralis on leaves treated with the approximate LC₅₀ or LC₉₅ dose for 6–48 h. The exposure time required to produce appreciable mortality (relative to LC values) within the treated population was found to be 24 h.     

Haematogenous septic arthritis in foals: Short‐ and long‐term outcome and analysis of factors affecting prognosis

Synovial sepsis represents a major cause of morbidity and mortality in foals; however, there are no studies focusing on foals particularly at risk during the first 2 months of life. Our objective was to analyse outcome in foals aged <2 months with haematogenous septic arthritis and to identify prognostic factors and compare the effects of two different lavage procedures on outcome. Sixty foals with synovial sepsis were used for our retrospective study in which medical records, online data and telephone interviews were utilised to analyse prognostic factors, and determine short‐ and long‐term survival and athletic performance of foals treated at Evidensia Equine Specialist Hospital, Helsingborg, between 2008 and 2014. Overall survival to discharge was 80% (48/60). Time to long‐term follow‐up ranged from 6 months to 6.5 years. Forty/60 (67%) horses survived long‐term. Four/8 (50%) of the nonsurvivors at long‐term follow‐up had been subjected to euthanasia due to sequelae of joint sepsis. Of the long‐term survivors, 37/40 (92.5%) achieved athletic soundness. Overall long‐term outcome for athletic soundness was 37/60 (62%). Prognostic factors based on historical, clinical or laboratory data, or the use of through‐and‐through needle lavage compared to endoscopic lavage as the first procedure, could not be identified. The present study demonstrates a more favourable prognosis than previously reported, with 80% of foals with synovial sepsis surviving to discharge, and approximately 60% achieving athletic soundness. However, the study was limited by a small population size, which may account for the failure to verify statistically significant prognostic factors.     

Basic husbandry and clinical assessment of the amphibian patient.

The veterinarian presented with an amphibian patient must be prepared to assess both the animal's medical condition and its husbandry record; good health is inextricably linked to proper care and diet. This article provides the clinician with guidelines for maintaining amphibians in captivity, including information on climate control and lighting, housing and cage enrichment, and nutrition. The article also covers questions to ask when taking a history, methods of restraint, and practical advice on the equipment and techniques used to conduct a complete physical examination of the amphibian patient.     

Characterization and plant expression of a glyphosate-tolerant enolpyruvylshikimate phosphate synthase

BACKGROUND: Glyphosate tolerance is a dominant trait in modern biotech crops. RESULTS: A gene encoding a glyphosate-tolerant EPSP synthase (aroA(1398)) from bacterial strain ATX1398 was cloned and characterized. The protein is initiated at a GTG translational start codon to produce a protein that provides robust glyphosate resistance in Escherichia coli (Mig) Cast & Chalm. The aroA(1398) protein was expressed and purified from E. coli, and key kinetic values were determined (K(i) = 161 microM; K(m)(PEP) = 11.3 microM; k(cat) = 28.3 s(-1)). The full-length enzyme is 800-fold more resistant to glyphosate than the maize EPSP synthase while retaining high affinity for the substrate phosphoenol pyruvate. To evaluate further the potential of aroA(1398), transgenic maize events expressing the aroA(1398) protein were generated. T(0) plants were screened for tolerance to glyphosate sprays at 1.3x commercial spray rates, and T(1) plants were selected that completely resisted glyphosate sprays at 1x, 2x and 4x recommended spray rates in field trials. CONCLUSION: These data suggest that aroA(1398) is a suitable candidate for conferring glyphosate tolerance in transgenic crop plants.