A field study was carried out on the year-long residual activity of the insect growth regulator (IGR) pyriproxyfen (Nylar 0.5G) in comparison with methoprene (Altosid® XRP Pellets) against mosquito developmental stages in catch basins in northwestern Riverside County, southern California. Pyriproxyfen was applied at 75, 100, 125, 150, 175 g per catch basin and methoprene at 3.5 g per catch basin. A total of 80 catch basins (10 per each treatment and 20 for control) were used. Posttreatment observations of catch basins were carried out at weekly intervals, with all pupal collections reared to adults. Mosquito species composition in this study, consisting mostly of Culex species (693), was predominated by Cx. quinquefasciatus (92.8%), followed by Cx. erythrothorax (5.5%), Cx. tarsalis (1.2%), Cx. stigmatosoma (0.3%), and Cx. thriambus (0.2%). Activity of both IGRs was expressed as percent inhibition of adult emergence (% IAE). Data generated on % IAE showed that, like methoprene, pyriproxyfen provided complete control of mosquitoes at 75, 125, and 175 g per catch basin up to 50 wk posttreatment at the Riverside amusement park, whereas its activity against mosquitoes in catch basins treated with 100 g and 150 g at the Eastvale site was short-lived, up to 48 wk. Water samples, bioassayed against laboratory-reared, 4th-stage larvae of Cx. quinquefasciatus 1–2 wk after the 50-wk-long study, showed evidence of significant % IAE (∼50) by pyriproxyfen at the 2 higher rates (125 g, 175 g) used at the amusement park. In conclusion, pyriproxyfen can be used to effectively control mosquitoes in catch basins for 48–50 wk, depending on the rate of application.

No abstract

Offshore oil and gas production platforms must undergo (possibly) expensive abandonment operations at the end of field life. In Cook Inlet Alaska, lessees are required, at abandonment, to dismantle and remove materials, machinery, equipment, etc. and return the leased lands in good order and condition as required under the oil and gas leases. Failure to complete abandonment responsibilities allows a claim for damages, as well as causing a default of the lease. In the worst-case scenario, default forces the landowner to step in and assume the responsibility of abandonment operations. To mitigate this risk, the landowner requires of the lessee financial guarantees such as bonds or independent escrow accounts funded to cover the cost of abandonment. At the Middle Ground Shoal Field in Alaska the landowner (State of Alaska) considers the value of the oil and gas reserves as collateral. This reduces other mitigation mechanisms that may be required of smaller independent producers when taking an assignment of the leases and facilities from giant, multinational, integrated oil firms. Accepting underlying proven reserves as collateral lowers the overhead costs to lessees, and frees investment dollars for incremental field development and exploration. Introduction Of the 16 current platforms in Cook Inlet, 14 were installed and began operations prior to 1969.1 Large, multinational oil and gas firms owned and operated these platforms and they were initially constructed for a twenty to twenty-five year life. The firms were so financially large, and the economic life of the reservoirs (with subsequent discoveries) extended so far in the future, that abandonment obligation was implicitly guaranteed through self-insurance. Cook Inlet Production has declined from 83 million barrels per year (b/y) in 1970 to just 11 million b/y in 1999. One large, multinational has previously offered all its Cook Inlet infrastructure up for sale and another has sold its two platforms to a much smaller independent. A third has sold its oil production to an independent producer while retaining its gas production interest. This ongoing change in the industry structure in Cook Inlet presents special risks to local stakeholders. Landowners asked themselves the question, would the new entrants have the financial strength to meet abandonment obligations (that are now much nearer in the future and with fewer reserves left in the ground) as required by the lease terms? Unlike a regulator, a landowner (royalty owner) is motivated in large part by profit (or royalties from production). Ninety-nine percent of oil and gas production in the state is from state lands and the State of Alaska is both a landowner and lessor.Therefore the State and oil and gas producers are aligned on many fronts. Both want production to be large and sustained. Both want costs to be minimized to encourage a long, productive field life: the producer to earn profits from their investment and labor, and the owner to collect royalties from the oil and gas reserves of the land. However, each has special concerns related to the different demands on their profitability. Well-meaning, but often vague, demands representing honest concerns of stakeholders raise the nominal costs to producers. There is no economic incentive for the landowner to accept every stakeholder demand (as a government landowner is often pressured) at any cost to the producer. The economic incentive directs the landowner to restrict the mitigation of risk to only what is incurred (or believed to incur). This strict principle serves as a natural deterrent to unnecessary costs.