DOI: 10.5061/dryad.sqv9s4n5p
title: Data from: Comparing the efficacy of control strategies for infectious disease outbreaks using field and simulation studies

description: Diseases characterized by long distance inoculum dispersal (LDD) are among
 the fastest spreading epidemics in both natural and managed landscapes.
 Management of such epidemics is extremely challenging because of
 asymptomatic infection extending at large spatial scales and frequent
 escape from the newly established disease sources. We compared the
 efficacy of area- and timing-based disease management strategies in
 artificially initiated field epidemics of wheat stripe rust and
 complemented with simulations from an updated version of the spatially
 explicit model EPIMUL, using model parameters relevant to field epidemics.
 The model was further used to expand the number of epidemic mitigations
 beyond that feasible to incorporate in the field. The field experiment was
 conducted for two years in two locations having different climatic
 conditions. Culling and protection treatments were applied at different
 times after epidemic initiation and to different spatial extents
 surrounding the outbreaks. In each experiment, treatments were replicated
 four times in plots 33.5 m long and 1.52 m wide with a 0.76 x 0.76 m
 inoculated focus centered within each plot. Disease gradients were
 assessed along the center lines of the plots at 1.52 m intervals both
 upwind and downwind from the focus. Both field and simulation results
 indicated that control measures applied over the entire population were
 highly effective in suppressing the epidemics by more than 99% but may not
 always be logistically and economically feasible at large spatial scales.
 Comparison between the variable sized treatment areas and application
 timings suggested that implementing contiguous premises (CP) cull at 1 day
 after first sporulation in the outbreak focus reduced rust by 52 and 60%
 in Corvallis and Madras, respectively. However, altering the cull size did
 not significantly affect the disease epidemic development, which suggested
 that early timing had a greater influence in suppressing the epidemics
 than did increased area of application. However, sufficiently large,
 treated areas may compensate for a delay in application timing to some
 extent. Results from these replicated treatments may help to devise
 appropriate management strategies for other LDD pathogens. 
description: In this study, we compared the efficacy of different control
 strategies for management of epidemics caused by LDD pathogens using field
 experiments and simulation studies. These control strategies included
 area-based treatments, application timing, and a combination of both
 tactics. We parameterized the compartment based SEIR model ‘EPIMUL’ using
 model parameters relevant to the wheat stripe rust pathosystem and
 compared outputs with results from the field studies. Field experiments
 were conducted at two different locations in Oregon, one at the Hyslop
 Crop Science Field Research Laboratory in Corvallis and the other at the
 Central Oregon Agriculture Research and Extension Center in Madras for two
 consecutive winter wheat seasons, 2018-2019 and 2019-2020. All experiments
 in both locations were planted with an older club wheat (Triticum aestivum
 ssp. compactum) cultivar called ‘Jacmar’. Plots were planted with the long
 axis oriented parallel with the anticipated predominant wind direction
 during the time of epidemic spread. Stripe rust was established in the
 center (0.762 x 0.762 m) area of each plot. At both locations, the
 experimental design was a randomized complete block with seven treatments
 and four replications per treatment. Different disease control treatments
 were applied to either the outbreak focus area or the general
 population. End of season WSR prevalence (percentage of leaf area covered
 by stripe rust lesions, assuming a maximum of 100 lesions per tiller) was
 assessed visually in each treatment plot. The
 compartment based SEIR model EPIMUL was used to simulate the effect of
 different mitigation practices for the control of epidemic outbreaks and
 to complement the field results. In our field experiment, we tested only a
 limited number of treatments because of logistical constraints. Without
 these limitations in EPIMUL we were able to test an extended range of
 timing and size of the cull and fungicide treatments, including different
 efficacy levels of the fungicide, to better understand the effect of
 timing and extent of control practices in the control of disease
 epidemics.
description: Please consider README_for_Data.pdf for the
 instruction on how to use data. All the codes used in the analysis have
 been included. If you have any questions, please write to 
 Professor Christopher C. Mundt
 (mundtc@science.oregonstate.edu)