Globally consistent response of plant microbiome diversity across hosts and continents to soil nutrients and herbivores.

All multicellular organisms host a diverse microbiome composed of microbial pathogens, mutualists, and commensals, and changes in microbiome diversity or composition can alter host fitness and function. Nonetheless, we lack a general understanding of the drivers of microbiome diversity, in part because it is regulated by concurrent processes spanning scales from global to local. Global-scale environmental gradients can determine variation in microbiome diversity among sites, however an individual host's microbiome also may reflect its local micro-environment. We fill this knowledge gap by experimentally manipulating two potential mediators of plant microbiome diversity (soil nutrient supply and herbivore density) at 23 grassland sites spanning global-scale gradients in soil nutrients, climate, and plant biomass. Here we show that leaf-scale microbiome diversity in unmanipulated plots depended on the total microbiome diversity at each site, which was highest at sites with high soil nutrients and plant biomass. We also found that experimentally adding soil nutrients and excluding herbivores produced concordant results across sites, increasing microbiome diversity by increasing plant biomass, which created a shaded microclimate. This demonstration of consistent responses of microbiome diversity across a wide range of host species and environmental conditions suggests the possibility of a general, predictive understanding of microbiome diversity.

A randomized trial of a one-time pest intervention: impact on childhood asthma outcomes.

Objectives: To evaluate the effects of a one-time, apartment-level Integrated Pest Management (IPM) intervention on healthcare utilization and asthma symptoms among children with persistent asthma living in households with a pest infestation.Study design: In a randomized controlled trial of 384 children aged 5-12 years with persistent asthma, we assigned 183 to receive IPM and 197 to usual care (UC). The primary outcome was healthcare utilization from hospital and Medicaid claims records. Secondary outcomes included caregiver-reported asthma symptoms, pest infestation levels, missed days of school due to asthma, and rescue medication use.Results: The entire cohort improved over the study period, with significant but equivalent declines in mean healthcare utilization in both groups. IPM group had fewer days with reduced activity due to asthma (p = 0.04) and larger declines that fell short of statistical significance in asthma symptom days (p = 0.22), severe symptoms (p = 0.16), missed school (p = 0.27) and rescue medication use (p = 0.27). Both roach (p = 0.001) and mice (p = 0.11) infestations decreased much more in the IPM group than the UC group.Conclusions: After a one-time, apartment-level IPM intervention, we found no difference in health care utilization, but fewer days of reduced activity and consistent suggestive evidence of clinically meaningful improvements relative to usual care across other secondary outcomes. Coupled with the established effectiveness of IPM in reducing allergens and scientific consensus on pest-related allergens as asthma triggers, these findings support adding home pest control to traditional medical management of children with severe asthma.

Dollar Spot Suppression on Creeping Bentgrass in Response to Repeated Foliar Nitrogen Applications.

Dollar spot is caused by the fungus Clarireedia spp. and is the most economically important disease of golf course turfgrass in temperate regions of the United States. Previous research has demonstrated that nitrogen (N) fertilization may reduce dollar spot severity, but the results have been inconsistent, and the impact of N as part of repeated foliar fertilization applications to golf course putting greens remains unclear. Two independent trials were replicated in Madison, Wisconsin and Glenview, Illinois in the 2015, 2016, and 2017 growing seasons. The objective of the first trial was to evaluate the effect of four different N rates applied as urea (4.9, 9.8, 19.4, and 29.3 kg N/ha applied every 2 weeks) on dollar spot severity, and the objective of the second trial was to evaluate the effect of three N sources (calcium nitrate, ammonium sulfate, and ammonium nitrate applied every 2 weeks) on dollar spot severity. Results from the N rate trial at both locations indicated that only the highest (29.3 kg N/ha) rate consistently reduced dollar spot severity relative to the nontreated control. Nitrogen source had minimal and inconsistent impacts on dollar spot severity based on location and year. Although these results show that meaningful reductions in dollar spot severity can be achieved by manipulating N fertilizer application rates, the rate of N needed for disease suppression may be impractical for most superintendents to apply and result in undesirable nontarget impacts.

Broadening Participation in Scientific Conferences during the Era of Social Distancing.

Virtual conferences can offer significant benefits but require considerable planning and creativity to be successful. Here we describe the successes and failures of a hybrid in-person/virtual conference model. The COVID-19 epidemic presents the scientific community with an opportunity to pioneer novel models that effectively engage virtual participants to advance conference goals.

Temperature Impacts on Soil Microbial Communities and Potential Implications for the Biodegradation of Turfgrass Pesticides.

Maintaining healthy turfgrass often results in the use of pesticides to manage weed, insect, and disease pests. To identify and understand potential nontarget impacts of pesticide usage while still maintaining attractive and functional turfgrass sites, it is important to improve our understanding of how pesticides degrade in various environments throughout the growing season. Temperature heavily influences microbial community composition and activity, and the microbial community often heavily influences pesticide degradation in soil ecosystems. Pesticide transformation products generated through the action of soil microbial degradation networks can vary in their toxicity, with the potential result that a pesticide applied in the spring at 10°C could produce different transformation products with different toxicological impacts than the sample pesticide applied to the same site at 22°C. The objective of this review is to examine past research surrounding soil microbial activity related to pesticide degradation and provide a foundation for how the soil microbiome interacts with pesticides and how seasonal temperature variations may influence those interactions.