Differences in Small Plot and On-Farm Trials for Yield Response to Foliar Fungicide in Soybean

Transcriptional responses of fluxapyroxad-induced dysfunctional heart in zebrafish (Danio rerio) embryos

Fluxapyroxad (FLU) is a succinate dehydrogenase inhibitor (SDHI) fungicide used in controlling crop diseases. Potential toxicity to aquatic organisms is not known. We exposed zebrafish to 1, 2, and 4 μM FLU for 3 days. The embryonic zebrafish showed developmental cardiac defects, including heart malformation, pericardial edema, and heart rate reduction. Compared with the controls, cardiac-specific transcription factors (nkx2.5, myh7, myl7, and myh6) exhibited dysregulated expression patterns after FLU treatment. We next used transcriptome and qRT-PCR analyses to explore the molecular mechanism of FLU cardiotoxicity. The transcriptome analysis and interaction network showed that the downregulated genes were enriched in calcium signaling pathways, adrenergic signaling in cardiomyocytes, and cardiac muscle contraction. FLU exposure repressed the cardio-related calcium signaling pathway, associated with apoptosis in the heart and other manifestations of cardiotoxicity. Thus, the findings provide valuable evidence that FLU exposure causes disruption of cardiac development in zebrafish embryos. Our findings will help to promote a better understanding of the toxicity mechanisms of FLU and act as a reference to explore the rational use and safety of FLU in agriculture.

Yield to the data: some perspective on crop productivity and pesticides

The scientific consensus is that pesticide use maximizes crop yields in the face of pest and disease pressures. Often, the debate then becomes a "so what" question (e.g., a percent or two increase in yield is inconsequential, so why use pesticides at all?). We set out to help give technical and lay audiences an objective and quantitative sense of what it means for pesticides to protect crop yields from two perspectives: (i) the number of additional hectares required to produce the same amount of food without the use of pesticides; and (ii) increased calorie production and people fed. Using available seeding and yield data for Canada and United States from 2015 to 2019 for common field crops, a user-friendly interface was developed that allows for the coarse calculation of land preserved and caloric increases for specific scenarios (e.g., jurisdiction, crop, percent yield increase). We found that land preserved would range from 145 883 to 11 590 255 ha and the number of adults fed would range from 1 333 814 to 100 016 319 depending on the crop and the country. Our hope is that this simple tool will provide a fuller sense of what changes in crop yields mean, and their implications for environmental protection and food security. © 2022 Society of Chemical Industry.

Meta-Analysis of Soybean Yield Response to Foliar Fungicides Evaluated from 2005 to 2018 in the United States and Canada

Random-effect meta-analyses were performed on data from 240 field trials conducted between 2005 and 2018 across nine U.S. states and Ontario, Canada, to quantify the yield response of soybean after application of foliar fungicides at beginning pod (R3) stage. Meta-analysis showed that the overall mean yield response when fungicide was used compared with not applying a fungicide was 2.7% (110 kg/ha). Moderator variables were also investigated and included fungicide group, growing season, planting date, and base yield, which all significantly influenced the yield response. There was also evidence that precipitation from the time of planting to the R3 growth stage influenced yield when fungicide was used (P = 0.059). Fungicides containing a premix of active ingredients from multiple groups (either two or three ingredients) increased the yield by 3.0% over not applying a fungicide. The highest and lowest yield responses were observed in 2005 and 2007, respectively. Better yield response to fungicides (a 3.0% increase) occurred when soybean crops were planted not later than 21 May and when total precipitation between planting and the R3 application date was above historic averages. Temperatures during the season did not influence the yield response. Yield response to fungicide was higher (a 4.7% increase) in average yield category (no spray control yield 2,878 to 3,758 kg/ha) and then gradually decreased with increasing base yield. Partial economic analyses indicated that use of foliar fungicides is less likely to be profitable when foliar diseases are absent or at low levels.