RESUMO
Runs of the endangered wild salmon/steelhead in the Columbia River basin may be only two to seven percent of historic levels. These fish are a common-pool resource, where stakeholders over-consume, pollute rivers and oceans, block passage with dams and culverts, operate net pen fish farms, and plant huge numbers of hatchery fish that compete with and hybridize wild fish. Rivers provide free or subsidized services that stakeholders covet, however recovery of the endangered wild fish requires that peoples utilizing the rivers and the ocean must constrain their behavior, often reducing their profit. A new Environmental Impact Statement (EIS) and cost-benefit analysis are in progress for recovery of the endangered wild salmon/steelhead in the Columbia River basin. New regulations require surveys of U.S. households to measure the non-use benefits of salmon/steelhead recovery that can be important for endangered species. We review the 2002 EIS for juvenile salmon migration on the lower Snake River tributary to find mistakes to avoid in the new EIS and in other recovery studies.
Assuntos
Oncorhynchus mykiss , Salmão , Migração Animal , Animais , Análise Custo-Benefício , RiosRESUMO
Insecticide resistance in the lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), can pose a serious threat to their successful management in broiler chicken farms in Arkansas. Resistance and cross-resistance were determined in lesser mealworm populations collected from two broiler farms in Arkansas, with different insecticide application histories. Farm M was treated with insecticides over the past 10 yr, whereas Farm S had no insecticidal usage history. Concentration-mortality bioassays using selected insecticides were conducted on adults and seventh-instar larval beetles. A probit analysis suggested the M population to be resistant to cyfluthrin and tetrachlorvinphos, while the S population was susceptible to both compounds. The M population showed no cross-resistance to imidacloprid, spinosad, or chlorfenapyr. The M and S populations were similar in their susceptibility to imidacloprid, spinosad, and chlorfenapyr. The suitability of imidacloprid and spinosad, and further testing of chlorfenapyr as a potential candidate for lesser mealworm control is discussed.
Assuntos
Besouros/efeitos dos fármacos , Resistência a Inseticidas , Inseticidas/farmacologia , Criação de Animais Domésticos , Animais , Arkansas , Galinhas , Besouros/crescimento & desenvolvimento , Larva/efeitos dos fármacos , Aves DomésticasRESUMO
Green June beetle, Cotinis nitida (L.), is an important pest of grapes, peaches, blackberries, blueberries, apples, and pears. Currently, there is no inexpensive, commercially available lure or trap that could serve monitoring green June beetle adults. The objective of this study was to develop and optimize an inexpensive bottle trap baited with isopropanol to attract and capture green June beetle adults. Bottle traps baited with 8 mm diameter cotton wicked dispensers emitted from 9 to 43 ml isopropanol in 48 h and maintained that alcohol at a fairly constant concentration compared with the prototypical bottle trap with large surface evaporation of isopropanol poured into the bottom of the trap. Over 5 d, the isopropanol in the wicked dispensers remained at the same stable concentration of 45-44.5%, whereas isopropanol concentration in the bottom of prototypical traps dropped from 45% to approximately 11% after 24 h and to 0.2% by 48 h. Bottle traps with isopropanol dispensers and cotton wicks of 4, 6, or 8 mm in diameter caught significantly more green June beetles than did prototypical bottle traps with no dispensers. Isopropanol concentrations of 45.5, 66, and 91% attracted more green June beetle adults than the lower concentrations. Significantly more green June beetle adults were attracted to traps with dispensers set at 1.3 m height than those at lower heights, and traps topped with a blue, orange, or white band captured more green June beetle adults than those with bands of other colors. The optimized bottle trap is made from recycled transparent polyethylene terephthalate beverage bottle (710-ml; 24 oz.) with a blue, orange, or white band, baited with an 8 mm cotton wick dispenser of 45.5% isopropanol and hung at a height of 1.3 m. Cost and uses for this trap are discussed.
Assuntos
2-Propanol/administração & dosagem , Besouros , Entomologia/instrumentação , Animais , Cor , Entomologia/economia , Feminino , MasculinoRESUMO
Three travel cost models are used to estimate non-fishing recreation demand at the Snake River reservoirs recreation area in eastern Washington. The opportunity cost of time is specified in the "traditional" and McConnell-Strand models as a fraction of the exogenous market wage rate and in the two-step decision model as a function of socioeconomic attributes of the recreationists. Benefits per person per trip were $90, $35, and $46 respectively, for the three models. Boaters visit the site more than three times as often as non-boaters resulting in higher annual benefits for boaters.
Assuntos
Conservação dos Recursos Naturais , Recreação , Modelos Teóricos , Rios , WashingtonRESUMO
The rice stink bug, Oebalus pugnax (F.), is a key pest of heading rice, Oryza sativa L. (Poales: Poaceae), in the southern United States. Sweep net sampling is the recommended method for sampling rice stink bug in rice, but there currently exists no specific recommendation for sweep length, and a large amount of variation likely exists amongst samplers. The objectives of this study were to determine the role that sweep length plays in sampling accuracy and determine the feasibility of using sweep lengths smaller than 180°. When monitoring sweep lengths by consultants, producers, and researchers, a large amount of variation in sweep length and a significant linear relationship between sweep length and rice stink bug catch per 10 sweeps was observed. Sweep length was then controlled at three levels (0.8, 1.8, and 3.5 m) and a change from 0.8 to 1.8 m in sweep length led to an increase on average of 2.28 rice stink bugs per 10 sweeps. These data suggest knowledge of sweep length is vital, and paired with large amounts of observed variation in sweep length, recommending a specific sweep length is ideal. Using Taylor's values, it was determined that 1.8 m sweeps resulted in density estimates that were as reliable as 3.5 m (180°) sweeps, suggesting a longer sweep length was not necessary. A 1.8 m sweep length recommendation would create an easier sampling regimen that is still reliable, which could lead to more accurate action threshold decisions being made for rice stink bug if it increases adoption in consultants and producers.
Assuntos
Heterópteros , Oryza , Animais , Ninfa , Densidade Demográfica , Reprodutibilidade dos TestesRESUMO
This study explored the biology of raspberry crown borer, Pennisetia marginata (Harris) (Lepidoptera: Sesiidae), in Arkansas and the optimum timing for insecticide and nematode applications. The duration of P. marginata's life cycle was observed to be 1 yr in Arkansas. Insecticide trials revealed that bifenthrin, chlorpyrifos, imidacloprid, metaflumizone, and metofluthrin efficacy were comparable with that of azinphosmethyl, the only labeled insecticide for P. marginata in brambles until 2005. Applications on 23 October 2003 for plots treated with bifenthrin, chlorpyrifos, and azinphosmethyl resulted in >88% reduction in larvae per crown. Applications on 3 November 2004 of metaflumizone, metofluthrin, and bifenthrin resulted in >89% reduction in larvae per crown. Applications on 7 April 2005 for metofluthrin, imidacloprid, bifenthrin, metaflumizone, and benzoylphenyl urea resulted in >64% reduction in the number of larvae per crown. Applications on 6 May 2004 did not reduce larval numbers. The optimum timing for treatments was found to be between October and early April, before the larvae tunneled into the crowns of plants. Applying bifenthrin with as little as 468 liters water/ha (50 gal/acre) was found to be as effective against larvae as higher volumes of spray. Nematode applications were less successful than insecticides. Nematode applications of Steinernemafeltiae, Steinernema carpocapsae, and Heterorhabditis bacteriophora reduced larvae counts per plant by 46, 53, and 33%, respectively.
Assuntos
Controle de Insetos , Inseticidas , Mariposas/fisiologia , Animais , Inseticidas/administração & dosagem , Larva/crescimento & desenvolvimento , Larva/fisiologia , Estágios do Ciclo de Vida , Mariposas/crescimento & desenvolvimento , Nematoides/fisiologiaRESUMO
Drosophila suzukii Matsumara, also referred to as the spotted wing drosophila, has recently expanded its global range with significant consequences for its primary host crops: blueberries, blackberries, raspberries, cherries, and strawberries. D. suzukii populations can increase quickly, and their infestation is difficult to predict and prevent. The development of effective tools to detect D. suzukii presence in new areas, to time the beginning of activity within a crop, to track seasonal activity patterns, and to gauge the effectiveness of management efforts has been a key research goal. We compared the efficiency, selectivity, and relationship to fruit infestation of a range of commonly used homemade baits and a synthetic formulated lure across a wide range of environments in 10 locations throughout the United States. Several homemade baits were more efficient than apple cider vinegar, a commonly used standard, and a commercially formulated lure was, in some configurations and environments, comparable with the most effective homemade attractant as well as potentially more selective. All alternative attractants also captured flies between 1 and 2 wk earlier than apple cider vinegar, and detected the presence of D. suzukii prior to the development of fruit infestation. Over half the Drosophila spp. flies captured in traps baited with any of the attractants were not D. suzukii, which may complicate their adoption by nonexpert users. The alternative D. suzukii attractants tested are improvement on apple cider vinegar and may be useful in the development of future synthetic lures.
Assuntos
Mirtilos Azuis (Planta) , Drosophila/fisiologia , Controle de Insetos , Feromônios/farmacologia , Rubus , Animais , Mirtilos Azuis (Planta)/crescimento & desenvolvimento , Drosophila/efeitos dos fármacos , Rubus/crescimento & desenvolvimento , Estados UnidosRESUMO
A laboratory bioassay was developed for determining the toxicity of spinosad, chlorfenapyr, and thiamethoxam against the eggplant flea beetle, Epitrix fuscula Crotch, on eggplant foliage. Four days after initial exposure, LC50 values were 1.99, 2.50, and 0.88 ppm for spinosad, chlorfenapyr, and thiamethoxam, respectively. By dividing the recommended field rate in ppm by the LC50 value, a field toxicity ratio was determined and ranged from 13.5 for spinosad to 73.9 for thiamethoxam. The high ratios suggest that field rates for all three insecticides could likely be reduced. This was supported by field studies in 2000 in which reduced rates of spinosad and thiamethoxam significantly reduced flea beetle numbers on eggplant. Mortality produced by thiamethoxam occurred more quickly than that for the other tested materials as shown with LT50 values of 1.8, 3.0, and 3.6 and days for thiamethoxam, chlorfenapyr, and spinosad, respectively. Persistence studies indicated that while all three of the tested compounds initially produced high levels of mortality, chlorfenapyr and thiamethoxam produced 50% or greater mortality after 6 d. Our data suggest that future management strategies for E. fuscula on eggplant can be successfully altered to meet the changing needs of the producer. Spinosad was recently registered, is effective against the E. fuscula, and offers a viable alternative to carbamate and pyrethroid insecticides. Thiamethoxam and chlorfenapyr offer high levels of toxicity to E. fuscula and upon registration will offer additional effective tools for management.