Antifeedant and toxic effects of acetogenins from <Emphasis Type="Italic">Annona montana</Emphasis> on <Emphasis Type="Italic">Spodoptera frugiperda</Emphasis>

Several species of the large family of tropical plants Annonaceae have been intensely investigated over the last 20 years, mainly because of the discovery of annonaceous acetogenins. These compounds are powerful cytotoxics, with potential applications as insecticides, antiparasitics, acaricides, fungicides, and antitumor drugs. Annona montana Macfad. (Annonaceae) grows in Santa Cruz de la Sierra, Bolivia, where an infusion of leaves is used for the treatment of lice, influenza, and insomnia. The major acetogenins from a Bolivian collection of A. montana, annonacin (1), cis-annonacin-10-one (2), densicomacin-1 (3), gigantetronenin (4), murihexocin-B (5), and tucupentol (6), were evaluated for their antifeedant and toxic effects on Spodoptera frugiperda Smith (Lepidoptera: Noctuidae), a serious pest affecting corn crops in Argentina. All the acetogenins produced 100% mortality during the larval or pupal stages at 100 μg of treatment per gram of diet. In addition, compounds 2, 3, and 4 deterred more than 80% feeding at the same dose. Relative toxicity values of LD₅₀ for the strongest larvicidal compounds 1, 2, and 4 were determined, indicating that the three compounds are effective natural insecticides. This is the first report on the antifeedant and toxic effects produced by the particular type of acetogenins, the mono-THF acetogenins, on the lepidopteran S. frugiperda. No correlation was detected between the toxicity of the mentioned compounds to larvae and the known capacity of the acetogenins 1, 2, and 4 to inhibit the NADH oxidase, indicating that the inhibition of the mitochondrial complex I is not the only cause for larval mortality of S. frugiperda.     

Toxicity nanoinsecticide based on clove essential oil against Tribolium castaneum (Herbst)

This study aimed to characterize nanoparticles loaded with clove (Syzygium aromaticum) essential oil-based polyethylene glycol (PEG) and to know their insecticidal activity against red flour beetle (Tribolium castaneum). The nanoparticles have irregular shapes in good dispersion. The nanoformulation could not enhance clove oil contact toxicity to T. castaneum, but could protect the oil from degradation and evaporation while simultaneously allowing sustained release, as indicated by the continued high toxicity for 16 weeks of storage.     

Evaporation ponds as a drainwater disposal management option

Constructed evaporation ponds are being utilized for disposalof saline subsurface drainage waters in San Joaquin Valley,California. These terminal evaporation ponds are located inhydrologically closed basins and/or regions with no surfacedrainage out of the valley. The saline drainwaters disposedinto the ponds are sodium-sulfate or sodium-sulfate-chloridetype waters and upon desiccation produces mirabilite andhalite. The drainwaters contain excessive levels of traceelements from geochemical origins. The trace element of mostconcern, is selenium because it bioaccumulates in the aquaticfood chain and causes death and deformity of waterbirdsattracted to the pond environment. At the present, the onlyeconomic drainwater disposal option in the southern. portionof the valley is evaporation ponds. The operation of theseponds is heavily regulated by waste discharge requirements toreduce and mitigate wildlife impacts. A case study onevaporation ponds and bird usage from a drainage districtillustrates the extensive monitoring and mitigation required.The prognosis is evaporation basins will be needed for theforeseeable future unless breakthroughs occur in economic andeffective drainwater treatment and drainwater reuseoptions.     

A Bayesian Approach to Estimating Agricultural Yield Based on Multiple Repeated Surveys

Forecasting the end-of-year crop yield is critical for agricultural decision-making and inherently difficult. Historically, a panel of commodity specialists known as the Agricultural Statistics Board convene regularly to set estimates based on expert review of a combination of survey data and administrative/auxiliary information. To make this process less subjective and more repeatable, we develop a Bayesian hierarchical model that produces superior yield forecasts/estimates, while quantifying different sources of uncertainty. The proposed hierarchical model naturally combines information from multiple monthly surveys measured on different temporal supports, including a field measurement survey and two farmer interview surveys. The dependence between the monthly updated surveys and the serial dependence of the annual yield are incorporated at different levels of the hierarchy. The effectiveness of our approach is demonstrated through an application from the US Department of Agriculture. Empirical results indicate that the hierarchical model produces superior forecasts to both the panel of experts and the composite estimator developed by Keller and Olkin (Technical Report, National Agricultural Statistics Service, 2002), while providing an accurate measure of uncertainty.     

A note on endoparasites of wild ostriches (Struthio camelus) in the Mokolodi Nature Reserve,Gaborone, Botswana

A study was undertaken to investigate the prevalence of endoparasites of wild ostriches at Mokolodi Nature Reserve, Gaborone, over a 7-month period. Large numbers of strongyle eggs were recovered from faecal material in April and September and a decline in the strongyle egg counts was evident during June and July. Noteworthy was the absence of helminth eggs in faecal samples collected from chicks and coccidia oocysts from any of the ostriches.     

Advanced Treatment Technologies in the Remediation of Seleniferous Drainage Waters and Sediments

Bioaccumulation of selenium (Se) in wetlands and evaporation ponds has created serious hazards to fish and waterfowl in the western United States. Agricultural drainage water is the main source for Se contamination in this region. Treatment technologies currently being evaluated to reduce the Se load in agricultural drainage water include physical, chemical and biological methods. This article focuses on ion-exchange, reverse osmosis, solar ponds, chemical reduction with iron, microalgal-bacterial treatment, volatilization, biological precipitation, and flow-through wetlands to remove Se in water. Advantages and disadvantages of each technology are evaluated and assessed in terms of cost-effectiveness and practical applications in dealing with large volumes of drainage water. With intense research in treatment technologies, it is feasible that a combination of biological, chemical and physical techniques may be employed in the development of a cost-effective strategy to treat agricultural drainage water.