Quantifying economic and environmental tradeoffs of walnut arthropod pest management

Many arthropod pesticides used by California walnut growers have been linked to water quality impairment. However lower risk alternatives are often associated with higher costs. The purpose of this paper was to: (1) identify currently practiced pest management strategies with probable high water quality impact, (2) quantify the importance of factors which affect economic tradeoffs associated with reducing water quality impact, and (3) identify pest management strategies that could potentially lower water quality impact with less economic consequence. An integrated analysis using environmental, economic and pesticide use data revealed that 96% of the pest management strategies analyzed were candidates for reducing the impact on water quality. Replacement of current pesticides by alternative pest controls lowered probable impact, but resulted in an economic tradeoff in the form of higher costs for the majority of growers. If biological control could eliminate the need for miticides and aphicides, this tradeoff could be replaced by savings for nearly half of the sample analyzed. This cost savings would most likely be realized by growers who currently have low numbers of pests that are not candidates for biological control, and relatively high use of organophosphates and miticides. The results indicated that if these pest management strategies had been replaced by alternative strategies and biological control, then total organophosphate, pyrethroid, and miticide active ingredient use would have been reduced by an average of 5 kg/hectare per year, while simultaneously lowering the grower’s pest management costs by an average of $128/hectare, thus contributing to both economic and environmental long-run sustainability.     

Rewarding farmers for delivering vascular plant diversity in managed grasslands: A transdisciplinary case-study approach

Due to lack of appropriate economic incentives offered by current markets the provision of ecosystem services by farmers is poorly rewarded. This study aimed to correct for this market failure by establishing a regionally-scaled market-based payment scheme for ecosystem services. Payments to farmers were linked to ecological goods representing differently ranked quality-levels of vascular plant diversity that were used as proxies for ecological services derived from managed grasslands. To reward the provision of ecological goods, we designed a novel market-based payment scheme that comprised a combination of a payment by results approach with an auction mechanism. Our results demonstrated that an appropriately designed payment scheme at a regional scale could support farming systems that are managed for delivering ecological goods in addition to the production of market goods such as food and fibre. Hence, instead of maximising economic profit through high-input management practices farmers within the case-study region had, for the first time, the possibility to diversify their total income risk by producing verifiable ecological goods of grassland plant diversity.     

Single-molecule DNA sequencing of a viral genome

The full promise of human genomics will be realized only when the genomes of thousands of individuals can be sequenced for comparative analysis. A reference sequence enables the use of short read length. We report an amplification-free method for determining the nucleotide sequence of more than 280,000 individual DNA molecules simultaneously. A DNA polymerase adds labeled nucleotides to surface-immobilized primer-template duplexes in stepwise fashion, and the asynchronous growth of individual DNA molecules was monitored by fluorescence imaging. Read lengths of >25 bases and equivalent phred software program quality scores approaching 30 were achieved. We used this method to sequence the M13 virus to an average depth of >150x and with 100% coverage; thus, we resequenced the M13 genome with high-sensitivity mutation detection. This demonstrates a strategy for high-throughput low-cost resequencing.