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Adulticides applied against mosquitoes can reduce vector populations during times of high arbovirus transmission. However, impacts of these insecticides on pollinators and other non-target organisms are of concern to mosquito control professionals, beekeepers and others. We evaluated mortality of Culex quinquefasciatus and Apis mellifera when caged insects were exposed to low and high label rates of four common adulticides (Aqua-Pursuit™ [permethrin], Duet® [prallethrin + sumithrin], Fyfanon® [malathion] and Scourge® [resmethrin]) at six distances up to 91.4 m from a truck-mounted ultra-low-volume sprayer. Honey bee mortality was both absolutely low (61 m had limited impacts on honey bee mortality while providing effective mosquito control.

A surgical technique was developed to isolate the arterial supply to the periodontal ligament, pulp and gingiva of the canine mandibular 4th premolar, and to measure the pressure and flow therein. This model system was used to study the interaction between tooth loading and periodontal blood flow. Intrusive forces of less than 350 N were found to produce negligible alteration of the measured blood flow, while loads of 1050 N produced a reduction of flow equivalent to an increase in vascular resistance of approximately 10 per cent, with no effect on arterial pressure. The increase in flow on removal of load was greater than the reduction seen on application, suggesting that reactive hyperemia may occur in the periodontal tissues. The phenomenon of periodontal pulsation first studied by Parfitt ( J. dent. Res. 39 , 608–618) in humans, was examined in the dog as a part of the present work. It was found that the pulsation of the canine mandibular 4th premolar was still in evidence under applied loads 230 times that which Parfitt found to obliterate the movement of the human incisor. This may be taken to indicate that the density and architecture of the periodontal vasculature may, in part, be determined by the loads applied to the teeth during function.

Tissue fluid pressures were monitored in the periodontal ligaments of 19 mandibular canine teeth. Resting (no load) pressures were recorded and changes in the pressure which accompanied the application and removal of forces up to 500 g. All parameters were reexamined after the animals were killed by exsanguination. The resting intraperiodontal pressure (IPP) was −1.86 ± 1.00 mmHg (mean ± 95 per cent confidence limits), markedly less than values obtained by other investigators. As these dogs were positioned with their mandibular canines at a higher elevation relative to the rest of the body than other workers have used, this may indicate that the pressure in the ligament is subject to postural variation. The resting IPP was not correlated with systemic blood pressure, and did not change significantly after exsanguination. Trauma to the ligament raised the resting IPP to −0.36 ± 1.93 mmHg. Application of load resulted in an immediate increase in pressure which decayed rapidly (halving-time less than 1 s). Removal of the load produced the inverse pattern, but with a reduced peak pressure and a longer halving-time. Trauma increased the halving-time for the decay of the load-induced pressures to the point that the pressure increases were judged to be sustained rather than transient. The pressure changes produced by the application of forces to the teeth were small compared to the loads applied, suggesting that the free fluids of the periodontal ligament make only a minor contribution to tooth support.