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An understanding of how fertilizer input affects pest populations and, consequently, the need for pesticide use would allow for the development of more effective integrated management strategies. The present study addressed the response of walnut aphid Chromaphis juglandicola (Kaltenbach) (Hemiptera: Aphididae) populations to different levels of nitrogen application to walnut seedlings and the relationship between aphid density and chlorophyll content index (CCI), a non-invasive measure of foliar nitrogen, for mature trees in commercial walnut orchards. Although added nitrogen significantly increased soluble nitrogen content, CCI and soluble nitrogen:phosphorus ratios in the foliage of walnut seedlings, there was no effect on walnut aphid population growth. Similarly, there was no relationship between aphid density and CCI for mature trees in the field. A neutral response suggests that walnut aphid population growth on potted seedlings is limited by factors other than soluble nitrogen, such as other nutrients, amino acid composition or defensive compounds. Consequently, fertilizer management appears unlikely to effectively contribute to the control of C. juglandicola in commercial walnut orchards.

Background: Pesticide drift is a serious environmental and safety concern that affects all of US agriculture. A number of mitigation techniques to reduce pesticide drift have been recommended by industry, academic and government agencies. These techniques are very costly or reduce the efficacy of the pest control product and have not been implemented by US agriculture., Results: When using a novel spray technique (Air-in), pesticide drift was significantly reduced by between 53% and 99% at 7.6 m from the orchard drip line when compared to the grower standard. This technique not only reduced pesticide drift, but also maintained or improved the amount of pesticide residue deposited (by 0.7-2.6-fold) and the percentage pesticide coverage (by 1.0-1.4-fold) with different air-blast speed sprayers on almond, walnut and pistachio., Conclusion: The Air-in technique shows great promise in reducing pesticide drift while maintaining or improving pesticide coverage with minimal cost to the grower., (© 2020 Society of Chemical Industry.)

The effects of plant quality on natural enemies are often overlooked in planning and executing biological control programs for insect pests in agriculture. Plant quality, however, could help to explain some of the observed variation in effectiveness of biological control, as it can indirectly influence natural enemy populations. In this study, we used the walnut aphid Chromaphis juglandicola (Kaltenbach) to address the effect of increased nitrogen availability to the host plant on parasitism by the specialist parasitoid Trioxys pallidus (Haliday). In laboratory experiments with walnut seedlings, a higher chlorophyll content index of the foliage in response to added nitrogen was correlated with a decrease in the number of mummies produced by female parasitoids over a 24-h period but an increase in the proportion and the size of female offspring. In field sampling of walnut orchards, there was no relationship between the percent parasitism of walnut aphids by T. pallidus and the chlorophyll content index of the trees. Nitrogen fertilizer and plant quality can clearly affect biological control and should be given greater consideration in integrated pest management., (© The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Agriculture today places great strains on biodiversity, soils, water and the atmosphere, and these strains will be exacerbated if current trends in population growth, meat and energy consumption, and food waste continue. Thus, farming systems that are both highly productive and minimize environmental harms are critically needed. How organic agriculture may contribute to world food production has been subject to vigorous debate over the past decade. Here, we revisit this topic comparing organic and conventional yields with a new meta-dataset three times larger than previously used (115 studies containing more than 1000 observations) and a new hierarchical analytical framework that can better account for the heterogeneity and structure in the data. We find organic yields are only 19.2% (±3.7%) lower than conventional yields, a smaller yield gap than previous estimates. More importantly, we find entirely different effects of crop types and management practices on the yield gap compared with previous studies. For example, we found no significant differences in yields for leguminous versus non-leguminous crops, perennials versus annuals or developed versus developing countries. Instead, we found the novel result that two agricultural diversification practices, multi-cropping and crop rotations, substantially reduce the yield gap (to 9 ± 4% and 8 ± 5%, respectively) when the methods were applied in only organic systems. These promising results, based on robust analysis of a larger meta-dataset, suggest that appropriate investment in agroecological research to improve organic management systems could greatly reduce or eliminate the yield gap for some crops or regions.

Self-medication is a specific therapeutic behavioral change in response to disease or parasitism. The empirical literature on self-medication has so far focused entirely on identifying cases of self-medication in which particular behaviors are linked to therapeutic outcomes. In this study, we frame self-medication in the broader realm of adaptive plasticity, which provides several testable predictions for verifying self-medication and advancing its conceptual significance. First, self-medication behavior should improve the fitness of animals infected by parasites or pathogens. Second, self-medication behavior in the absence of infection should decrease fitness. Third, infection should induce self-medication behavior. The few rigorous studies of self-medication in non-human animals have not used this theoretical framework and thus have not tested fitness costs of self-medication in the absence of disease or parasitism. Here we use manipulative experiments to test these predictions with the foraging behavior of woolly bear caterpillars (Grammia incorrupta; Lepidoptera: Arctiidae) in response to their lethal endoparasites (tachinid flies). Our experiments show that the ingestion of plant toxins called pyrrolizidine alkaloids improves the survival of parasitized caterpillars by conferring resistance against tachinid flies. Consistent with theoretical prediction, excessive ingestion of these toxins reduces the survival of unparasitized caterpillars. Parasitized caterpillars are more likely than unparasitized caterpillars to specifically ingest large amounts of pyrrolizidine alkaloids. This case challenges the conventional view that self-medication behavior is restricted to animals with advanced cognitive abilities, such as primates, and empowers the science of self-medication by placing it in the domain of adaptive plasticity theory.

On Match Day in 1991, Broadlawns Medical Center in Des Moines, Iowa, learned that no residents had matched for the family practice residency program. In the 1992 match, the medical center filled all its residency positions, and repeated the success in the 1993 and 1994 matches. Broadlawns affected this impressively rapid turnaround through a strong commitment to bring its program to a level competitive with leading family practice residency programs, substantive changes to the structure and curriculum of the program, and significant expenditures of time, resources and personal energy. The Broadlawns' case illustrates the need for family practice residency programs to position themselves as strong competitors in the residency market.

The purpose of the present investigation was to examine the effects of 'platform' fashion shoes on response time in vehicle braking. Seventeen subjects participated in two test sessions: in one they wore platform shoes and in the other normal footwear. Although all subjects were accustomed to wearing either type of footwear, platform shoes significantly slowed their braking responses, compared with normal shoes (0.91 vs 0.81 s, respectively). This differential response time represents an increased stopping distance of 1.42 ft (433 mm) for each 10 mile/h (16 km/h) of vehicle speed.