Use of a 0.25 per cent fipronil pump spray formulation to treat canine cheyletiellosis

Two outbreaks of cheyietieilosis are described. In one of the outbreaks, a human member of the household was also affected. A 0.25 per cent flpronil pump spray formulation was applied to the affected and in-contact animals. A permethrin spray was used in an attempt to eliminate environmental contamination. One month later, the affected animals were reexamined. No evidence of Cheyletiella mites could be found. A second application of fipronil was undertaken. No further outbreaks were reported during an eight month follow-up.     

Laboratory study of the effects of two nitrification inhibitors on greenhouse gas emissions from a slurry-treated arable soil: impact of diurnal temperature cycle

An automated laboratory soil incubation system enabled the effects on gaseous emissions from a soil to be quantified accurately, when amended with slurry plus a nitrification inhibitor: dicyandiamide (DCD), or 3,4-dimethylpyrazole phosphate (DMPP). Nitrification inhibitors applied with slurry under simulated Portuguese conditions were very efficient in reducing N₂O emission, and did not increase CH₄ emissions significantly, when the soil was predominantly aerobic. The inhibitors were also indirectly effective in reducing N₂O emissions due to denitrification during a subsequent anaerobic phase. All gaseous emissions followed strong diurnal patterns that were positively correlated with soil temperature and obeyed a Q₁₀=2 relationship. The widespread use of DCD and DMPP inhibitors with slurry applied to Portuguese soils could have the potential to reduce N₂O emissions from this source by ten- to 20-fold.     

Recovery of benthic invertebrate communities in silver bow creek,montana, following improved metal mine wastewater treatment

Silver Bow Creek, a tributary of the Clark Fork River in southwest Montana, has been affected by metal mining and domestic wastes for over 100 yr. The invertebrate community was monitored at five stations from 1972 through 1983 to determine both the longitudinal and temporal patterns of recovery following major improvements in mine wastewater treatment. This treatment dramatically reduced metal concentrations in the mine discharge. Despite markedly improved water quality, no invertebrates were collected in Silver Bow Creek until 1975, when small numbers of invertebrates (primarily chironomids) were collected at the furthest downstream stations. A few invertebrates (<75 m^?2) were collected for the first time at Stations 1 and 2 in 1981, although the lower stations still had much greater densities (> 1600 m^?2). The earliest colonizers at each station were chironomids, empidids, and oligochaetes. In 1982, 10 yr after initiation of improved water quality, aquatic insect populations were over 1800 m^?2 at all five stations. Populations dropped in 1983, but upper and lower stations had comparable densities suggesting that the stream is responding to a common stress such as high snowmelt runoff. The relatively long recovery time is partially attributed to the lack of an undisturbed headwater source of colonizers.     

Deformation monitoring at mount st. Helens in 1981 and 1982

For several weeks before each eruption of Mount St. Helens in 1981 and 1982, viscous magma rising in the feeder conduit inflated the lava dome and shoved the crater floor laterally against the immobile crater walls, producing ground cracks and thrust faults. The rates of deformation accelerated before eruptions, and thus it was possible to predict eruptions 3 to 19 days in advance. Lack of deformation outside the crater showed that intrusion of magma during 1981 and 1982 was not voluminous.     

Soils, agriculture, and society in precontact Hawai'i

Before European contact, Hawai'i supported large human populations in complex societies that were based on multiple pathways of intensive agriculture. We show that soils within a long-abandoned 60-square-kilometer dryland agricultural complex are substantially richer in bases and phosphorus than are those just outside it, and that this enrichment predated the establishment of intensive agriculture. Climate and soil fertility combined to constrain large dryland agricultural systems and the societies they supported to well-defined portions of just the younger islands within the Hawaiian archipelago; societies on the older islands were based on irrigated wetland agriculture. Similar processes may have influenced the dynamics of agricultural intensification across the tropics.     

Impact of microbial activity on the leaching of soluble N forms in soil

The hydrological transport of low-molecular weight organic nitrogen (LMWON) compounds has received little attention in the literature, particularly relative to inorganic nitrogen (N), with less attention given to the decoupling of the carbon (C) and N cycles following rainfall events. We determined the impacts of the soil biota on the transport of N compounds in a loam soil, using ¹⁵N and ¹³C to trace the vertical transport of ¹⁵N¹³C-urea, ¹⁵N¹³C-amino acids, ¹⁵NO₃, and ¹⁵NH₄ through the soil profile, following simulated rainfall events. This research has demonstrated that biotic assimilation leads to rapid decoupling of the C and N cycles during leaching, with C transport limited to the soil surface (<?2 cm), whereas N which was stored within the soil profile during a single rainfall event could be remobilised and leached (a further 2–6 cm) following an additional rainfall event.     

Activity of some new pyrethroids against Blattella germanica L.

The activities of natural and synthetic pyrethroids against male German cockroaches (Blattella germanica) were examined by means of dusting and direct spraying techniques. NRDC 107 (5-benzyl-3-furylmethyl (+)-trans-chrysanthemate) was the most active compound in killing cockroaches. Pyrethrins gave the most rapid knockdown and were 60% as active as NRDC 107 (Bioresmethrin) in killing power. Tetramethrin and the corresponding (+)-trans-ester gave rapid knockdown. Only (+)-trans-allethrin [(+)-trans-chrysan-themate of (±)-allethrolone] provided useful knockdown and killing power together. Piperonyl butoxide had a relatively stronger synergistic action with less active killing agents. The rate of knockdown during the first few minutes of exposure was not altered greatly by piperonyl butoxide.